Emirates B773 accident on 03 August 2016, Interim Statement

There were no aircraft systems or engine abnormalities up to the time of the Accident

emirates_b773_a6-emw_dubai_160803_3

Air Accident Investigation Sector
General Civil Aviation Authority
The United Arab Emirates
Accident – First Interim Statement –
AAIS Case No: AIFN/0008/2016
Runway Impact During Attempted Go-Around

Operator: Emirates
Make and Model: Boeing 777-31H
Nationality and Registration: The United Arab Emirates, A6-EMW
Place of Occurrence: Dubai International Airport
State of Occurrence: The United Arab Emirates
Date of Occurrence: 3 August 2016

Occurrence Brief  (See: Going around with no thrust. Emirates B773 accident at Dubai on August 3rd, 2016, interim report)
Occurrence Reference : AIFN/0008/2016
Occurrence Category : Accident
Name of the Operator : Emirates
Manufacturer : The Boeing Company
Aircraft Model : 777-31H
Engines : Two Rolls-Royce Trent 892
Nationality : The United Arab Emirates
Registration : A6-EMW
Manufacture Serial Number : 32700
Date of Manufacture : 27 March 2003
Flight Hours/Cycles : 58169/13620
Type of Flight : Scheduled Passenger
State of Occurrence : The United Arab Emirates
Place of Occurrence : Runway 12L, Dubai International Airport
Date and Time : 3 August 2016, 0837 UTC
Total Crewmembers : 18 (two flight and 16 cabin)
Total Passengers : 282
Injuries to Passengers and Crew : 30, four serious, 26 minor (The number of injured has been updated since the Preliminary Report was published)
Other Injuries : One firefighter (fatal)
Nature of Damage : The Aircraft was destroyed

Investigation Objective
This Investigation is performed pursuant to the United Arab Emirates (UAE) Federal
Act No. 20 of 1991, promulgating the Civil Aviation Law, Chapter VII ̶ Aircraft Accidents,
Article 48. It is in compliance with Part VI, Chapter 3 of Part VI, Chapter 3, of the Civil Aviation Regulations (CARs) of the United Arab Emirates, and in conformity with Annex 13 to the Convention on International Civil Aviation.
The sole objective of this Investigation is to prevent aircraft accidents and incidents.
It is not the purpose of this activity to apportion blame or liability.
This first anniversary Interim Statement gives a brief of the Investigation progress
and should be read in conjunction with the Preliminary Report number AIFN/0008/2016 that was published on 5 September 2016.

This Interim Statement is released in accordance Standard 6.6 of ICAO Annex 13
and paragraph 7.4 of UAE CAR Part VI, Chapter 3.
Later Interim Statements/Reports, or the Final Report, may contain altered
information in case of new evidence becoming available during the ongoing investigation.

Investigation Process
The occurrence was classified as an Accident and the Air Accident Investigation
Sector (AAIS) of the United Arab Emirates assigned an Accident Investigation File Number AIFN/0008/2016 for the case.
The AAIS formed the Investigation team led by the investigator-in-charge (IIC) and
members from the AAIS for the relevant investigation aspects. The National Transportation Safety Board (NTSB) of the United States, being the State of the Manufacture and Design, and the Air Accidents Investigation Branch (AAIB) of the United Kingdom, being the State of Manufacture of the engines, were notified of the Accident and both States assigned Accredited Representatives assisted by Advisers from Boeing and Rolls-Royce. In addition, the Operator assigned an Adviser to the IIC. The AAIS is leading the Investigation and will issue a Final Report.
This Interim Statement is publicly available at:
http://www.gcaa.gov.ae/en/epublication/pages/investigationReport.aspx

Interim Statement
This first anniversary Interim statement gives a brief account of the progress of the
Investigation into the subject Accident. The statement is released in accordance Standard 6.6 of ICAO Annex 13 and paragraph 7.4 of UAE CAR Part VI, Chapter 3.
The Accident occurred on 3 August 2016 and involved an Emirates Boeing 777-300
Aircraft, registration A6-EMW, operating a scheduled passenger flight EK521, that had
departed Trivandrum International Airport (VOTV), India, at 0506 UTC for Dubai International Airport (OMDB), the United Arab Emirates. At approximately 0837:38 UTC, the Aircraft impacted the runway during an attempted go-around at Dubai International Airport.
The Aircraft sustained substantial structural damage as a result of the impact and its
movement along the runway and was eventually destroyed by fire. Twenty-one passengers, one flight crewmember, and four cabin crewmembers sustained minor injuries. Four cabin crewmembers sustained serious injuries. Approximately nine minutes after the Aircraft came to rest, a firefighter was fatally injured as a result of the explosion of the center wing fuel tank.
Regarding the operation of the flight the Investigation is working to determine and
analyze the human performance factors that influenced flight crew actions during the landing and attempted go-around.
In addition, the Investigation has reviewed and has identified safety enhancements
related to the validity of weather information that was passed to the flight crew, and
communication between air traffic control and the flight crew.
A detailed examination was performed of the Aircraft evacuation systems, including
the operation of emergency escape slides in a non-normal aircraft resting position, and the effects of wind on the escape slides.
A large number of aircraft systems were tested with the assistance of the manufacturers and analysis of the data downloaded indicates that there were no Aircraft systems or engine abnormalities up to the time of the Accident.

The UAE GCAA Air Accident Investigation Sector continues to collaborate with the
State authorities and other organizations involved in areas of interest including flight
operations, human performance, training standards, procedures, aircraft systems, passenger evacuation and airport emergency response.

This Interim Statement is issued by:
The Air Accident Investigation Sector
General Civil Aviation Authority
The United Arab Emirates
P.O. BOX 6558, Abu Dhabi.
Email: ACCID@gcaa.gov.ae

Source

1. United Arab Emirates, General Civil Aviation Authority, Air Accident Investigation Sector. Accident – First Interim Statement -AAIS Case No: AIFN/0008/2016

FURTHER READING

  1.  Going around with no thrust. Emirates B773 accident at Dubai on August 3rd, 2016, interim report
  2. When the error comes from an expert: The Limits of Expertise
  3. Let’s go around
  4. Speaking of going around
  5. Going around with all engines operating
  6. Multitasking in Complex Operations, a real danger
  7. The Organizational Influences behind the aviation accidents & incidents 

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minime2By Laura Duque-Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

Challenger loss of control in-flight by A380 wake vortex encounter

Interim Report, published May 2017. Bundesstelle für Flugunfalluntersuchung. BFU – German Federal Bureau of Aircraft Accident Investigation

Identification

Type of Occurrence: Accident. Date: 7 January 2017. Location: Enroute, above the Arabian Sea. Manufacturer / Model: 1) Bombardier / CL-600-2B16 (604 Variant) 2) Airbus / A380-861. Injuries to Persons: 1) Two severely injured passengers, two passengers and one flight attendant suffered minor injuries 2) None. Damage: 1) Aircraft severely damaged 2) None.

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Photos: Airbus A380-861 (C) Tim Bowrey. – Jetphotos.net  Bombardier CL-600-2B16 (C) Aktug Ates – Jetphotos.net

Factual Information

During cruise flight above the Arabian Sea, the Indian Ocean, approximately one minute after it had been passed overhead by an Airbus A380 on opposite course, the CL604 was subject to temporary loss of control.

After it had lost approximately 9,000 ft of altitude the pilots regained control of the aircraft and subsequently landed at an alternate aerodrome at Muscat Airport, Oman.

The accident occurred over international waters. Thus the BFU as representative of the State of Registry of the accident aircraft is responsible for the conduct of the investigation. In accordance with international regulations, the air accident investigation authorities of Oman, India, the United Arab Emirates, Canada, USA, and France will assist the BFU in this investigation.

History of the Flight

At 1152 hrs -0652 UTC (All times local, unless otherwise stated) the CL604 had taken off from runway 36 at Malé, Maldive Islands, for a flight to Al-Bateen, United Arab Emirates. Three crew members and six passengers were on board the airplane.

The Flight Data Recorder (FDR) recordings show that the CL604 autopilot had been engaged approximately one minute after take-off. At 0720 UTC the airplane reached cruise level FL340. At 0729 UTC the aircraft entered Indian airspace (Mumbai FIR) at the reporting point BIBGO and had received the clearance to fly to reporting point KITAL via route L894. At approximately 0818 UTC the co-pilot radioed reaching reporting point GOLEM.

At 0655 UTC an Airbus A380-861 (A380) had taken off at Dubai Airport, United Arab Emirates, for a flight to Sydney, Australia. The aircraft flew at FL350 with a southern heading.

The analysis of the flight data of both aircraft showed that at 0838:07 UTC the A380 had passed the CL604 overhead with a vertical distance of 1,000 ft.

At 0838:54 UTC the CL604, with engaged autopilot, began to slightly roll right. At the same time, a counter-rotating aileron deflection was recorded and fluctuation of the vertical acceleration began. In the subsequent approximately 10 seconds the airplane had a right bank angle of 4° to 6°. At 0839:03 UTC the right bank angle began to increase. Within one second the bank angle increased to 42° to the right. At the same time, the aileron deflection to the left increased to 20° and the vertical acceleration increased to 1.6 G. In the following second, vertical acceleration changed to -3.2 G.

At 0839:04 UTC a lateral acceleration of 0.45 G to the right was recorded. The pitch angle changed from about 3° to about 1°, then within one second increased to 9° and decreased again in the following second to -20°. At the same time, the FDR recorded a rudder deflection to the left reaching 11.2° after about two seconds whereas the bank angle changed from 42° right to 31° left.

Between 0839:05 UTC and 0839:10 UTC Indicated Airspeed (in knots) changed from approximately 277 KIAS to 248 KIAS. The N1 of the left engine of 95% began to decrease.

At 0839:07 UTC the validity of IRS parameter is lost, the lateral acceleration reached 0.94 g left, the autopilot disengaged, and a master warning, lasting seven seconds, was recorded.

Between 0839:09 UTC and 0839:41 UTC the FDR recorded a loss of altitude of approximately 8,700 ft. Large control surface deflections and acceleration were recorded. The speed increased and at 0839:31 UTC reached approximately 330 KIAS. At 0839:30 UTC the spoilers extended and 13 seconds later were retracted again. The N1 of the left engine had decreased to approximately 40% when the Interstage Turbine Temperature (ITT) began to increase and nine seconds later had reached 850°. The left engine was shut off.

At about 0856 UTC the Pilot in Command (PIC) informed the air traffic controller in Mumbai of the occurrence, declared the emergency and reported their position, altitude and their intention to fly via KITAL to Oman.

At about 0915 UTC the crew restarted the left engine. Subsequently, the airplane climbed to FL250. At about 0956 UTC the autopilot was re-engaged.

At 1105 UTC the CL604 landed at Muscat Airport.

The A380 continued the flight to Sydney and landed there at 1958 UTC.

The recordings of the Omani air traffic control services show that at about 0920 UTC the neighbouring Indian regional air traffic control Mumbai informed them that the CL604 was at FL230 and would probably pass the reporting point KITAL at 0937 UTC. Mumbai also informed ATC that via a relay station the information had been received that the airplane would divert to Oman. Initially, the reason for the low altitude was given by Mumbai ATC as being due to engine failure. At 0957:50 UTC the airplane was depicted on the Omani ATC radar. At 1014:14 UTC the CL604 reached reporting point KITAL.

Statements of the CL604 Pilots

According to the statement of the CL604 pilots, the PIC was Pilot Flying (PF) and the co-pilot Pilot Non Flying (PNF). The PIC stated that TCAS had drawn his attention to the opposite traffic. He then recognised the aircraft type A380, the airline, and informed the co-pilot. The PIC also stated that the A380 had passed them in opposite direction, slightly to the left and according to TCAS 1,000 ft above. He further stated that a short time later the airplane had been hit by the wake turbulence of the A380. The airplane had shook briefly, then rolled heavily to the left and the autopilot disengaged. Both pilots had actuated the aileron to the right in order to stop the rolling motion. But the airplane had continued to roll to the left thereby completing several rotations. Subsequently both Inertial Reference Systems (IRS), the Flight Management System (FMS), and the attitude indication failed. According to the pilots’ statements at the time of the accident both pilots had fastened their lap belts and in addition the co-pilot had worn his shoulder belts. According to the PIC he had lost his headset during the rolling motion of the airplane. The Quick Reference Handbook (QRH) had flown around the cockpit and was damaged. As a result individual pages had been scattered around the cockpit. The PIC explained since the sky had been blue and the ocean’s surface almost the same colour he had been able to recognize the aircraft’s flight attitude with the help of the clouds. Later both pilots had been able to recover the airplane at FL240 using control inputs on the aileron and later the rudder and slight elevator deflection. Regarding the left engine the PIC stated that he had observed that N1 and N2 had “run apart”. N1 had decreased severely. ITT had increased, reached more than 1,000°C, and the indication flashed red. Subsequently the engine was shut off. Based on the memory items the pilots were able to reactivate the IRS in attitude mode and fly the airplane again towards reporting point KITAL. Then the pilots used the cross bleed of the right engine to restart the left. After the second IRS had been reactivated and position and heading been entered manually into the FMS the autopilot was engaged again. After they had assessed the situation the flight crew decided to fly to Muscat.

Statements of the CL604 Flight Attendant

The flight attendant stated in an interview conducted by the BFU that during take-off and climb she had been seated in the jump seat with the seat belt fastened. She had opened the seat belt while they were passing FL100. At the time of the accident, she had been standing in the middle of the cabin preparing the service. Four of the six passengers had also not been seated. In her recollection, the airplane had turned three times around its longitudinal axis, during which the occupants had been thrown against the ceiling and the seats. Several of the passengers suffered injuries, some of which were bleeding. She herself suffered minor injuries. Using the on-board first aid kit she had attended to the passengers. In the further course of the flight she informed the pilots of the situation in the cabin and reassured the passengers.

Reconstruction of the encounter of the two airplanes

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Images: Interim Report Bundesstelle für Flugunfalluntersuchung. BFU – German Federal Bureau of Aircraft Accident Investigation 

Personnel Information

Pilot in Command CL604

The 39-year-old PIC held an Air Transport Pilot’s License (ATPL(A)) of the European Union issued in accordance with Part-FCL. It was first issued by the Luftfahrt-Bundesamt (LBA) and valid until 6 June 2014. The licence listed the ratings as PIC for CL604/605 and the Instrument Rating (IR) valid until 31 March 2017, and for single engine piston land (SEP).

His class 1 medical certificate was last issued on 26 September 2016 and valid until 8 October 2017.

His total flying experience was about 5,334 hours, about 4,564 hours of which were on type.

He had been employed by the operator as a pilot since October 2012.

On the day of the accident, the entire crew had begun their shift at 0500 UTC.

Co-pilot CL604

The 41-year-old co-pilot held an Commercial Pilot’s License (CPL(A)) of the European Union issued in accordance with Part-FCL. It was first issued by the LBA on 31 October 2013. The licence listed the ratings as co-pilot for CL604/605 and the Instrument Rating (IR), valid until 31 October 2017, and for single engine piston land (SEP) and Touring Motor Glider (TMG).

His class 1 medical certificate was last issued on 8 March 2016 and valid until 8 April 2017.

The co-pilot had a total flying experience of about 1,554 hours; of which 912 hours were on type.

Since November 2015 the co-pilot had been employed by the operator.

Meteorological Information

Pre-flight Meteorological Preparation CL604

The BFU was provided with the pre-flight preparation documentation of the CL604

flight crew including the weather data of 6 January 2017 at 2336 UTC.

According to the forecast tropopause was at approximately FL525 at a temperature

of -82°C.

For cruise level FL340 wind with 20 kt from north-west and a temperature of -42°C

were forecast.

The Significant Weather Fixed Time Prognostic Chart for the planned flight did not

contain any warnings of Clear Air Turbulence (CAT) for the area of the Arabian Sea.

Weather at the Time of the Accident

At the time of the accident it was daylight. According to the CL604 pilots’ statements very good Visual Meteorological Conditions (VMC) with blue skies prevailed. The ocean’s surface had been visible. In an estimated altitude of 3,000 to 4,000 ft AMSL the cloud cover had been 1/8 to 2/8. Condensation trails had not been visible.

No significant meteorological information (SIGMET) had been issued for the flight information region Mumbai (VABF).

According to the Digital Access Recorder (DAR) of the A380 the wind at their cruise level at FL350 came from about 315° with about 23 kt. The Static Air Temperature (SAT) was -44°C.

Wreckage and Impact Information

The accident occurred above international waters, the Arabian Sea, approximately 500 NM from any land.

The aircraft manufacturer determined that the airframe structure could not be restored to an airworthy state as it exceeded the airframe certification design load limits during the upset encounter. Therefore the aircraft is considered to be damaged substantially.

During a BFU investigation of the airplane no outer damages on fuselage, wings, and empennage, including control surfaces, were visible. There was no evidence of leakages (oil, fuel).

The inside of the passenger cabin showed damages on the seats and the panelling, as well as traces of blood. The armrests of the four seats in the front, installed in club arrangement, were either deformed or had fractured.

On the left side of the cabin two oxygen masks had fallen from their casings.

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Photo of the interior of D-AMSC after the upset (Photo: FlightServiceBureau) from The Aviation Herald   

Medical and Pathological Information

According to the operator, four passengers were treated at the hospital in Muscat.

One passenger suffered head injuries and a broken rib; another passenger had fractured a vertebra. The two passengers and the flight attendant, who had sustained minor injuries, suffered bruising and a fractured nose, respectively.

The two other passengers and the pilots remained unharmed.

Additional Information

Safety Case for Wake Vortex Encounter Risk due to the A380-800

An ad hoc Steering Group (SG) and a technical Work Group, comprising representatives from Joint Aviation Authorities (JAA), Eurocontrol, Federal Aviation Administration (FAA), Airbus and Det Norske Veritas (DNV), was set up in 2003 to specify safety requirements to ensure Wake Vortex Encounter (WVE) risk from the Airbus A380 will be acceptable. A safety case (A380 SG, 2006a) and supporting documentation has been produced.

Among others the following recommendations have been made:

wake 2Investigator in charge: Jens Friedemann

Excerpted from Bundesstelle für Flugunfalluntersuchung – German Federal Bureau of Aircraft Accident Investigation Interim Report

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On Mar 18th,  2017 The Aviation Herald received a draft of an EASA safety information bulletin regarding this accident, stating:

With the increase of the overall volume of air traffic and enhanced navigation precision, wake turbulence encounters in the en-route phase of flight above 10 000 feet (ft) mean sea level (MSL) have progressively become more frequent in the last few years.

The aim of this SIB is to enhance the awareness of pilots and air traffic controllers of the risks associated with wake turbulence encounter in the en-route phase of flight and provide recommendations for the purpose of mitigating the associated risks.

The draft reasons:

The basic effects of wake turbulence encounter on the following aeroplane are induced roll, vertical acceleration (can be negative) and loss or gain of altitude. The greatest danger is an induced roll that can lead to a loss of control and possible injuries to cabin crew and passengers. The vortices are also most hazardous to the following aircraft during the take-off, initial climb, final approach and landing.

However, en-route, the vortices evolve in altitudes at which the rate of decay leads to a typical persistence of 2-3 minutes, with a sink rate of 2-3 metres per second. Wakes will also be transported by the wind.

Considering the high operating airspeeds in cruise, the wake can be encountered up to 25 nautical miles (NM) behind the generating aeroplane, with the most significant encounters reported within a distance of 15 NM. This is larger than in approach or departure phases of flight.

The encounters are mostly reported by pilots as sudden and unexpected events. The awareness of hazardous traffic configuration and risk factors is therefore of particular importance to anticipate, avoid and manage possible wake encounters.

The draft issues following recommendations:

As precautionary measures, operators and pilots should be aware that:

– As foreseen in Reg. 965/2012 AMC1 to CAT.OP.MPA.170, the announcement to passengers should include an invitation to keep their seat belts fastened, even when the seat belt sign is off unless moving around the cabin. This minimises the risk of passenger injury in case of a turbulence encounter en-route (wake or atmospheric).

– As indicated in ICAO PANS-ATM, for aeroplanes in the heavy wake turbulence category or for Airbus A380-800, the word “HEAVY” or “SUPER”, respectively, shall be included immediately after the aeroplane call sign in the initial radiotelephony contact between such aeroplanes and ATS units.

– When possible, contrails should be used to visualise wakes and estimate if their flight path brings them across or in close proximity.

– When flying below the tropopause altitude, the likelihood of wake encounter increases. The tropopause altitude varies (between days, between locations).

– Upwind lateral offset should be used if the risk of a wake encounter is suspected.

– Timely selecting seat belt signs to ‘ON’ and instruct cabin crew to secure themselves constitute precautionary measures in case of likely wake encounters.

In the case of a wake encounter, pilots should:

– Be aware that it has been demonstrated during flight tests that if the pilot reacts to the first roll motion when in the core of the vortex, the roll motion could be amplified by this initial piloting action. The result can be a final bank angle greater than if the pilot would not have moved the controls.

– Be aware that in-flight incidents have demonstrated that pilot inputs may exacerbate the unusual attitude condition with rapid roll control reversals carried out in an “out of phase” manner.

– Be aware that if the autopilot is engaged, intentional disconnection can complicate the scenario, and the autopilot will facilitate the recovery.

– Avoid large rudder deflections that can create important lateral accelerations, which could then generate very large forces on the vertical stabiliser that may exceed the structural resistance. Although some recent aircraft types are protected by fly-by-wire systems, use of the rudder does not reduce the severity of the encounter nor does it improve the ease of recovery.

– Make use of specific guidance available through AOM for their specific type(s)/fleet.

ATS providers and air traffic controllers should:

Enhance their awareness about en-route wake turbulence risk, key factors and possible mitigations, based on the information provided in this document and other relevant material. This could be achieved through flyers, e-learning, and refresher training module.

Possible risk mitigations may consist of:

– Make use of the wake turbulence category (WTC) indication in the surveillance label and/or the flight progress strip (whether electronic or paper), and observe closely separated aeroplanes that are at the opposite extremes of the WTC spectrum;

– As the best practice, provide traffic information, advising “CAUTION WAKE TURBULENCE”, when you identify that a ‘HEAVY’ or ‘SUPER HEAVY’ wake category traffic is climbing or descending within 15 NM of another following traffic;

– Manage en-route traffic crossings such as, when possible while preserving safe tactical management of overall traffic in the sector, avoiding to instruct climb or descend to ‘HEAVY’ or ‘SUPER HEAVY’ traffic within 15 NM distance from another following traffic;

– If at all possible, avoid vectoring an aeroplane (particularly if it is LIGHT or MEDIUM category) through the wake of a HEAVY or SUPER HEAVY aeroplane where wake turbulence may exist.

REFERENCES:

  1. Bundesstelle für Flugunfalluntersuchung – German Federal Bureau of Aircraft Accident Investigation Interim Report. State File Number: BFU17-0024-2X. Published: May 2017
  2. EASA  Safety Publications Tool. Safety Information Bulletins
  3. The Aviation Herald

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minime2By Laura Victoria Duque Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day

Tailstrike and runway overrun

An undetected incorrect take-off weight inadvertently entered into the electronic flight bag during the pre-departure preparation led to the use of erroneous take-off performance parameters.

Some certification standards, procedures design, distraction management training and crew qualifications issues were found

Emirates A345 (2)

Photo (C) Alexei. Planespotters.net

Tailstrike and runway overrun

Melbourne Airport, Victoria

20 March 2009 – 22:25 local time

A6-ERG, Airbus A340-541

Australian Transport Safety Bureau

Publication date: 16 December 2011

Excerpts from ATSB final report

FACTUAL INFORMATION

History of the flight

On the night of Friday 20 March 2009, 257 passengers, 14 cabin crew and 4 flight crew boarded an Airbus A340-541, registered A6-ERG, for a scheduled passenger flight from Melbourne, Victoria, to Dubai, United Arab Emirates-UAE (The duration of the flight meant that an augmenting flight crew (captain and first officer) had to be carried to provide the operating flight crew with rest breaks during the flight.). The flight, operating as Emirates flight EK407, was scheduled to depart Melbourne at 2225 Australian Eastern Daylight-saving Time and had a planned flight time of 14 hours and 8 minutes (Unless otherwise annotated, the 24-hour clock is used in this report to describe the local time of day, Australian Eastern Daylight-saving Time, as particular events occurred. Australian Eastern Daylight-saving Time is Universal Coordinated Time (UTC) + 11 hours). The pre-departure preparation included the use of an electronic flight bag -EFB laptop computer in calculating the performance parameters for the takeoff from runway 16. The EFB calculation required the input of a range of data: wind speed and direction; outside air temperature; altimeter setting; take-off weight; flap configuration; air conditioning status; anti-ice selection; runway surface condition; and aircraft centre of gravity.

A base take-off weight figure (361.9 tonnes) was taken from data in the aircraft’s flight management and guidance system – FMGS. An additional tonne was added to that figure to allow for any minor last-minute changes in weight, making a total figure of 362.9 tonnes. When entering that take-off weight into the EFB, however, the first officer inadvertently entered 262.9 tonnes instead of 362.9 tonnes and did not notice that error.

Based on the weight and other input information, the EFB calculated take-off performance parameters (including reference speeds and engine power settings) for entry into the aircraft’s flight systems. The incorrect weight and the associated performance parameters were then transcribed onto the master flight plan for later reference. At about this time, the captain and first officer discussed an aspect of the standard instrument departure that appeared to cause some confusion between the flight crew.

The EFB was handed to the captain to check the performance figures before he entered them into the aircraft systems. While the captain was checking the figures entered into the laptop, the first officer was confirming the departure clearance with air traffic control. There were also activities taking place that involved other persons in the cockpit and forward galley area.

The captain’s checks were required to include a verbal check between the captain and first officer to compare the take-off weight in the FMGS with that used in the take-off performance calculation. That verbal check did not take place in this instance.

The captain entered the EFB performance figures into the FMGS and crosschecked them with the first officer against the values that were previously transcribed onto the flight plan.

The captain handed the EFB back to the first officer, who stowed the EFB before they both completed the loadsheet confirmation procedure. During that procedure, the first officer correctly read the weight from the FMGS as 361.9 tonnes but, when reading from the flight plan, stated 326.9 tonnes before immediately ‘correcting’ himself to read 362.9 tonnes (the amended figure that included a 1-tonne allowance for last minute changes). Among the other checks in the loadsheet confirmation procedure, the first officer read out the green dot speed of 265 kts from the FMGS. The captain accepted that speed and the procedure was completed (The aircraft’s best lift to drag ratio speed in the clean configuration (flaps and landing gear retracted). The speed is affected by aircraft weight and altitude only).

The flight crew completed the pre-departure preparation and at 2218:28, the aircraft was pushed back from the terminal 7 minutes ahead of schedule and was taxied to the northern end of runway 16 for takeoff. At 2230:46, ATC cleared the aircraft to line up and then cleared it for takeoff in front of an aircraft that was on final approach. The thrust levers were set to the take-off position and the aircraft accelerated along the runway.

At 2231:53, when the aircraft had reached the calculated rotation speed, the captain called ‘rotate’. The first officer, who was the pilot flying, applied a back-stick (nose up) command to the sidestick, but the nose of the aircraft did not rise as expected. The captain again called ‘rotate’ and the first officer applied a greater back-stick command. The nose began to rise, but the aircraft did not lift off from the runway. The captain selected take-off/go-around (TO/GA) thrust on the thrust levers. The engines responded immediately, and the aircraft accelerated as it passed off the end of the runway, along the stopway and across the grassed clearway. The aircraft became airborne 3 seconds after the selection of TO/GA but, before gaining altitude, it struck a runway 34 lead-in sequence strobe light and several antennae, which disabled the airport’s instrument landing system for runway 16.

Shortly after, the crew were alerted to a tailstrike by an automated message in the cockpit and a radio call from air traffic control (ATC). The crew decided to return to Melbourne to assess the damage.

After stabilising the aircraft in a normal climb, the captain informed ATC of the intention to climb to 5,000 ft and the need to jettison fuel prior to returning for landing. ATC cleared the crew to climb to 7,000 ft and radar vectored them over water to facilitate the fuel jettison.

At 2237, about 5 minutes after lift-off, the crew commenced planning for the approach and landing. The first officer retrieved the EFB from its stowage to carry out the landing performance calculations and determine a suitable landing weight. The EFB was still in the take-off performance module and the crew noticed that the weight used for the take-off calculations was about 100 tonnes below the aircraft’s actual take-off weight.

At 2239, while climbing to 7,000 ft, the augmenting first officer informed the flight crew that the aircraft was not pressurising. The captain asked the augmenting first officer to locate the procedures for action in the event of a tailstrike in the aircraft’s operational documentation. After reviewing the documentation, the augmenting first officer informed the captain that he was unable to find the procedure for a tailstrike (The operator’s Flight Crew Operating Manual did contain a procedure in the case of a tailstrike. The procedure specified that in the event of a tailstrike warning, the flight crew were to limit flight to 10,000 ft to minimise the stress on the airframe and return to an airport for damage assessment as soon as possible).

At 2246, the captain contacted ATC and declared a PAN. All four flight crew then discussed an appropriate landing weight and decided to jettison fuel for a landing weight of 280 tonnes. Although above the aircraft’s maximum landing weight, the crew chose 280 tonnes as a precaution in case several approaches were required. To ensure that there were no further performance calculation errors, the flight crew made three independent calculations of the landing performance using two different references – the EFB and the quick reference handbook (QRH).

At 2311, ATC informed the crew of debris and runway surface damage found during an inspection of the runway and surrounding area. Later, ATC updated the crew on the damage, informing them that the operator’s ground engineers had inspected some of the items retrieved and that they should expect ‘significant damage to the tail’.

During the flight, the flight crew communicated with the cabin crew primarily via the intercom system, although the purser was provided with a detailed briefing in the cockpit. Communication was predominantly with the purser; however, the captain also contacted the senior flight steward in the rear of the cabin to ask about the cabin crew’s observations during the takeoff.

The captain gave the passengers two briefings over the passenger address system. The briefings included basic information on the situation and advice on the fuel jettison and return to Melbourne.

On completion of the fuel jettison, the flight crew prepared for the approach and commenced a descent from 7,000 ft to 5,000 ft. At 2327, as they were passing through about 6,500 ft and slowing the aircraft, the captain heard an unusual rumbling sound. The sound was unexpected and caused a degree of concern among the flight crew. Moments later, the senior flight steward at the left rear door contacted the flight crew to advise that he could see and smell smoke in the rear cabin. The first officer contacted ATC, informing them of smoke in the cabin and requested clearance for an immediate approach. ATC cleared the flight crew to descend to 3,000 ft and, subsequently, for the approach to runway 34. The first officer briefed the purser on the possibility of an evacuation after landing.

At 2332, the crew changed to the Melbourne Tower radio frequency. At the request of the flight crew, the Melbourne Tower controller organised for the aviation rescue and fire fighting (ARFF) vehicles to be on the tower frequency to allow direct communication with the flight crew. As there were several ARFF vehicles involved, there was a significant amount of radio communication between ATC and ARFF vehicles during the latter stages of the approach. The first officer reported that the additional radio communication resulted in some distraction.

At 2336:29, 1 hour and 4 minutes after lift-off, the aircraft touched down on runway 34 and rolled to the end of the runway where it was met by the ARFF services vehicles. After the aircraft came to a stop on the runway, the captain made an announcement for the cabin crew to prepare for a possible evacuation.

The aircraft was briefly inspected by the ARFF services personnel for signs of smoke and fire. None were evident and the flight crew were cleared by ATC to taxi the aircraft to the terminal. The captain advised the cabin crew to revert to normal operations and taxied the aircraft back to the terminal where the passengers disembarked.

There were no injuries to the passengers or crew.

Damage to the aircraft

Inspection of the aircraft revealed serious damage to the underside of the rear fuselage, where the lower skin panels were abraded by contact with the runway surface. In some areas, the skin was worn through its full thickness and grass and soil was caught in the airframe structure. A service panel was dislodged and was found beyond the end of runway 16, along with numerous pieces of metal from the abraded skin panels.

The right side rear fuselage contained several contact marks. One contact mark, forward of the abraded area and immediately below the rear cargo door, was orange in colour consistent with the orange paint on the localiser near-field monitor antenna. Another contact mark was located adjacent to the skin abrasion and consisted of several fine, divergent marks running rearwards and slightly upwards. Numerous fuselage frames and stringers in the rear fuselage area were damaged by the abrasion and contact forces during the tailstrike. The damaged frames were deformed and several were cracked. The composite rear pressure bulkhead had cracked, and the bulkhead diaphragm support ring was deformed.

The inboard rear tyre on the left main landing gear had a scuff mark on its sidewall. The mark contained transferred material that was the same orange colour as the localiser antenna system.

The flight data recorder (FDR) was dislodged from its mounting rack immediately behind the rear pressure bulkhead and was found lying on the lower fuselage skin below and slightly to the rear of the mounting rack. The FDR was undamaged and contained recorded data from the commencement of the take-off roll until the dislodgement at 2232:05. The results of an examination of the FDR rack are in Appendix A on the final report.

Other damage

foto 1

Photo: Ground contact marks. From ATSB final report.

An inspection of the runway, stopway, clearway, and overrun areas identified multiple contact marks, consistent with the tailstrike and overrun. The aircraft’s tail contacted the runway at three locations, starting at 265 m, 173 m, and 110 m from the end of the runway, respectively. The contact marks contained white paint and metallic material, consistent with the construction and paint scheme of the underside of the aircraft.

There was a small drop-off at the end of the stopway that resulted in the fuselage losing contact with the ground until the point in the clearway, 67 m beyond the end of the runway. The final ground contact mark ended 148 m beyond the end of the runway.

To the south of the last ground contact mark, the fuselage contacted the runway 34 lead-in strobe light that was closest to the runway 16 end. That contact was slight and resulted in scrape marks on the support post and slight deformation of the lens shield. A small strip of white paint was located adjacent to the strobe light.

The aircraft struck the runway 16 localiser near-field monitor antenna and the main localiser antenna array. The localiser near-field monitor antenna support post was fractured at the base and fell in the approximate direction of takeoff. The antenna was damaged and the top of the support post was indented and exhibited white paint transfer.

Damage to the localiser antenna array was limited to one of the 16 antennae. The forward (runway) end of the damaged antenna was deformed and the composite cover was severely disrupted. The top of the forward end of the antenna had a black, rubber-like marking and the deformation of the antenna was consistent with an impact.

Personnel information

Operating flight crew

Captain

Table 1

The captain was rated on the Airbus A330-243, A340-313K and A340-541. In the preceding 90 days, the captain had operated only on A340-313K and A340-541 and was not current on the A330-243. The captain’s relevant qualifications and aeronautical experience are outlined in Table 1.

The captain had operated on flights to or from Melbourne on 18 occasions during the preceding 12 months, including four occasions as part of an augmenting crew.

First officer

Tabla 2

The first officer was rated on the Airbus A330-243, A340-313K and A340-541. In the preceding 90 days, the first officer had operated on all three aircraft types. The first officer’s relevant qualifications and aeronautical experience are outlined in Table 2.

The first officer had operated on flights to or from Melbourne on 14 occasions during the preceding 12 months, including four occasions as part of an augmenting crew.

Crew resource management

The communication between the operating crew members during the taxi and takeoff was in accordance with procedures and reflective of an open and effective cockpit environment. The first officer was the pilot flying during the takeoff and for the majority of the flight, so the captain conducted most of the communications with ATC and the cabin. The captain also asked the augmenting crew to calculate the landing data for the return to Melbourne and therefore the amount of fuel to be jettisoned.

Recorded information showed that the captain also included the augmenting crew in the discussions about the landing configuration and after-landing checks that would be required on their return to Melbourne. During that time, the captain made numerous decisions about the return to Melbourne, some of which were challenged by the crew before being resolved, in accordance with accepted crew resource management practices.

Flight crew alertness and fatigue

Fatigue can be defined as a state of impairment that can include physical and/or mental elements associated with lower alertness and reduced performance. Fatigue can impair individual capability to a level where a person cannot continue to perform tasks safely and/or efficiently.

The investigation examined the likelihood that the operating flight crew were fatigued at the time of the accident and the effect that fatigue may have had on their performance. Using sleep/wake data provided to the investigation by the operating flight crew, the fatigue biomathematical modelling system Fatigue Avoidance Scheduling Tool –FAST (Eddy, D.R; Hursh, S.R. (2001). Fatigue Avoidance Scheduling Tool (FAST). Brooks AFB, TX: AFRL/HEOA; 2001; Report No: AFRL-HEBR-TR-2001–0140) was used to assess the flight crew’s task effectiveness. FAST allows the user to input the quality of sleep as well as the duration of any sleep and work.

The calculations used by FAST were designed to produce a score denoting an individual’s task effectiveness. Both operating flight crew members had FAST scores that were towards the top of the effectiveness range. The operator also assessed flight crew fatigue using a different biomathematical modelling tool. The operator’s results for the operating flight crew from that tool correlated closely with the FAST scores.

The operating captain reported having 6 hours sleep in the 24 hours prior to the occurrence and 16 hours sleep in the 48 hours prior to the occurrence. The operating first officer reported having 8 hours sleep in the previous 24 hours and 12 hours sleep in the previous 48 hours.

There were no salient indications recorded on the CVR to indicate that either flight crew were fatigued; such as yawning and prolonged silence, or the disengagement of the crew from conversations.

Fire

Examination of the rear fuselage found no indications of a fire that could account for the smoke reported in the rear cabin.

The apparent smoke that was reported by the cabin crew was consistent with dust entering the fuselage through the abrasion when the tail was in contact with the ground beyond the end of the runway. The change in the pitch attitude while the aircraft was being configured for the approach altered the airflow around the rear fuselage, may have resulted in some of the dust collected in the abraded area entering the rear passenger cabin. The heat generated when the fuselage skins were abraded on the runway may have produced some vapours from the synthetic materials in that area (for example, paints and insulation materials) that produced an odour similar to combustion products.

Tests and Research

The inadvertent use of erroneous take-off data for performance calculations and subsequent takeoffs has been the subject of two research studies, one by the Laboratoire d’Anthropologie Appliquée (LAA) and the other by the Australian Transport Safety Bureau (ATSB). Both studies highlighted the widespread, systemic nature of this issue, with the ATSB paper identifying 31 occurrences from a 20-year period. In addition, the studies offered considerable insight into the factors influencing the use of erroneous data for takeoff and were used to conduct a more targeted comparison between the accident flight and similar events.

Take-off performance calculations

Accident flight scenarios

table 5

Following the accident, the operator provided one of the EFBs that was on board the aircraft during the accident flight.

The investigation entered the ambient conditions of the day and take-off weights of 262.9 and 362.9 tonnes respectively into that EFB to calculate the take-off performance parameter A summary of the results of those calculations is presented in Table 5.

Expected take-off performance

Tabla 6 y 7

The aircraft manufacturer calculated the expected take-off performance for the aircraft when a take-off weight of 362.9 tonnes was used in the performance calculations on the EFB, but when the actual aircraft weight was 361.9 tonnes. The resulting take-off speeds and distances are presented in Table 6.

Pos is the position along the runway measured from the point at which the brakes were released. The actual take-off distances travelled on the accident flight were calculated from the FDR data for comparison and are listed in Table 7.

Comparison of the A340-541 with the A330-243 and A340-313K

Table 8

The crew operated on the A330-243, A340-313K and A340-541. Table 8 provides a comparison of some of the key aircraft specifications that affect its take-off performance. (Engine thrust (kN each):  At take-off/go-around (TO/GA) thrust)

Variability of take-off performance parameters

The flight crew reported observing a wide range of take-off performance parameters during normal operations as well as significant variations in passenger loads across routes and aircraft types. Both the captain and first officer reported that this resulted in the take-off performance figures losing significance and becoming ‘just numbers’.

In order to examine the range of this variability, copies of the flight plans and load sheets for the 2 months prior to the accident were obtained from the operator for each of the four flight crew. There were 87 individual flights by the flight crew in that time…

There was significant variation in the take-off performance parameters during the 2-month period examined, and the erroneous parameters used during the accident flight lay within the range of values observed during that period. Furthermore, the following points were noted:

  • There was no direct correlation between an aircraft’s weight and the FLEX temperature.
  • Although the take-off reference speeds generally increased with increasing weight, the variation was not linear and the correlation was very weak.
  • The take-off reference speeds experienced by the crew varied by more than 50 kts.
  • All four flight crew had experienced take-off parameters in the A340-541 that were very similar to the erroneous values used on the accident flight.

Flight crew perception of the take-off acceleration during the accident flight

All four flight crew reported that their perception of the aircraft’s take-off acceleration was typical of a heavy A340, particularly a heavy A340-313K. The operating flight crew reported that they did not realise there was a problem with the aircraft’s acceleration until they had nearly reached the end of the runway, and the red runway end lights became more prominent. Both operating flight crews reported that during operations from some runways at other airports, it was common to see the red runway end lights as the aircraft lifted off.

Pre-departure preparation

Following arrival at the airport, the first officer proceeded directly to the aircraft to prepare for the flight. The captain completed a number of other tasks before proceeding to the aircraft, and the augmenting flight crew remained with the cabin crew while they completed their pre-departure briefing. Following that briefing, the augmenting flight crew went to the cockpit to assist the operating flight crew with their preparations.

The augmenting captain then proceeded to the crew rest station to check the intercom while the augmenting first officer completed the external checks of the aircraft. On returning to the cockpit, the augmenting captain sat in the second observer’s seat and the augmenting first officer waited in the forward galley because the ground engineers were in the cockpit and one was occupying the first observer seat.

Preparation for the flight included the initialization and configuration of the aircraft’s systems and the entry and review of the flight plan in the navigation computers. At 2155, noticing that the first officer had not configured the overhead panel, the captain completed the required actions. Those actions included activating the cockpit voice recorder (CVR). A review of the CVR found that the take-off performance calculation and associated actions were captured by the recording.

The timing of, and actions during the pre-departure preparation are outlined in the following tabulated format.

CVR1

CVR2

 

CVR3

CVR4

CVR5

CVR6

The leading ‘3’ in the flexible take-off weight value (FLTOW) that was transcribed on the flight plan was not consistent with the other ‘3’ numerals that were also transcribed by the first officer on the flight plan. This number appeared to have been changed from a ‘2’ to a ‘3’ (Figure 31). The effect of that alteration was to change the recorded flexible take-off weight value from 262.9 to 362.9 tonnes.

Figure 31

Initially, the first officer reported that he believed he had changed the FLTOW value, but could not recall when it was changed. Later, the first officer listened to a replay of the CVR recording at the ATSB audio laboratory. After hearing the verbal slip that was made when reading the flexible take-off weight during the loadsheet confirmation procedure, discussed above, the first officer recalled that was the time when he altered the ‘2’ to a ‘3’. He also reported that, at the time he made the alteration, he believed that he had transcribed the value incorrectly from the EFB onto the flight plan.

At about the time the loadsheet confirmation procedure was completed, the augmenting first officer entered the cockpit. At that point, the preparation was ahead of schedule.

The augmenting captain reported that, although not required by the operator’s procedures when in the augmenting captain role, he had a personal habit of checking the take-off performance calculations on the EFB. He did that by either reviewing those entered by the first officer or by obtaining the second EFB and completing the calculations himself. He reported that he did not have the opportunity to do this on the accident flight due to the first officer using the primary EFB and the number of people in the cockpit during the pre-departure preparation blocking access to the second EFB.

At 2218, following the completion of passenger loading and closure of the doors, the aircraft was pushed back from the terminal ahead of schedule. At 2218:36, the engine start procedure was commenced and all four engines were started. After obtaining taxi clearance from ATC, the crew taxied the aircraft to the northern end of runway 16.

Emirates A345

Photo (C) Zacair. Airplanes-Pictures.net

ANALYSIS

Introduction

The 20 March 2009 tailstrike and runway overrun involving the Airbus A340-541 aircraft, registered as A6-ERG, was the result of the inadvertent use by the flight crew of an erroneous data figure of 262.9 tonnes that was input during the take-off performance calculations. That input error produced erroneous take-off speeds and engine thrust settings that were used for the takeoff.

This analysis begins with an examination of the occurrence events, before discussing the individual actions and local conditions that affected the performance of the flight crew. The risk controls to prevent such an occurrence are then discussed. Several other topics of interest, including the use of the electronic flight bag (EFB) and fatigue are also considered.

Occurrence events

The investigation identified two occurrence events that contributed to the development of the accident. Those events included the over rotation, leading to a tailstrike, and a long take-off roll, leading to a runway overrun. The following discussion examines the factors in the over rotation and long take-off roll.

1. Over rotation and subsequent tailstrike

The damage in the rear lower fuselage and marks on the runway indicated that the aircraft sustained a tailstrike during takeoff. The smooth, positive backstick command by the first officer to raise the nose resulted in a rotation rate of about 3° per second, which was within the normal range. Therefore, it was unlikely that the first officer’s rotation technique contributed to the tailstrike.

The use of take-off reference speeds that were too low for the aircraft’s actual weight or flap configuration of 1+F, meant that the wings did not produce sufficient lift to raise the aircraft off the ground before the geometric pitch limit was reached, and the tail contacted the runway. The only relevant cockpit indication provided to the flight crew was the tailstrike pitch limit indicator on the primary flight display (PFD). It is unlikely that the flight crew had time to recognise that the aircraft had not lifted off at the expected pitch angle of about 8° before the aircraft reached the geometric limit of 9.5°. It was, therefore, unlikely that the flight crew could have identified the over rotation using the PFD indicator, given that the rotation rate of 3° per second would have given them about half a second to perceive the information and react.

The rotation maneuver was initiated at a speed lower than necessary for the aircraft’s weight and this meant that the wing was unable to provide sufficient lift for the aircraft to lift off as expected at the normal pitch attitude. The investigation concluded that the over rotation and tailstrike were due to the incorrect rotation speed and flap configuration for the actual weight of the aircraft.

2. Long take-off roll and subsequent runway overrun

The additional distance travelled by aircraft to reach V1, VR and VLOF was due to the acceleration being lower than required. The operation of the engines was normal and the thrust being produced was appropriate for the calculated FLEX temperature. Given there was no indication of a retarding force, such as a locked brake or excess aerodynamic drag, the low acceleration was the result of a lower thrust setting than that required for the actual aircraft weight.

The crew’s lack of awareness of the low acceleration until towards the end of the take-off roll meant that, by the time the captain selected Take-off/Go-around (TO/GA) thrust, a runway overrun was inevitable. The increased thrust from that selection increased the aircraft’s acceleration and resulted in the aircraft becoming airborne and climbing away from the ground much earlier than it would have otherwise. The captain’s selection of TO/GA, therefore, reduced the likely significant adverse consequences of the runway overrun.

Individual actions and local conditions 

There were a number of actions taken by the flight crew during the pre-departure phase that contributed to the accident, two of which directly influenced the occurrence events. Those were the:

  • use of erroneous performance data for the takeoff
  • lack of recognition of the degraded take-off performance until very late in the take-off run

1. Use of erroneous performance data

A direct comparison of the erroneous take-off reference speeds that were used in the takeoff with those derived by the investigation for the aircraft’s actual weight was not possible due to the differences in aircraft configuration associated with the different take-off weights. However, as previously discussed, the reduced take-off reference speeds and incorrect take-off configuration adversely impacted on the lift available for the takeoff. Compounding that reduction in lift, the significantly higher FLEX temperature resulted in a much lower engine thrust setting than necessary for the takeoff.

Although the recorded information showed that the erroneous figures were entered into the Flight Management and Guidance System (FMGS) during the pre-departure phase, there was no indication that the flight crew were aware that the take-off performance figures were incorrect until after the tailstrike.

2. Incorrect take-off weight entered into the EFB

The introduction into service of the EFB resulted in the take-off performance calculation changing from an interactive process of referencing charts and tables to a simple data entry and retrieval exercise. All of the calculations were performed by the computer and the results presented to the crew. The relatively simple actions of data entry and retrieval probably resulted in the process becoming quite automatic, with little conscious oversight by the crew members. Because of the automatic nature of this process, the crew member entering the data into the EFB would be unlikely to detect any errors made unless the software provided an error message or if there was a significant and unusual result.

There are a range of explanations for the entry of the erroneous take-off weight of 262.9 tonnes into the EFB by the first officer, including confusion with the zero fuel weight figure of 226.6 tonnes or a mental slip while adding the last-minute changes to the take-off weight in a busy, distracting environment. It was, however, considered most likely that the first officer made a typing slip, where the ‘2’ key was accidentally pressed instead of the adjacent ‘3’ key, and that he did not detect the error.

3. Erroneous take-off weight undetected

Three factors were identified as contributing to the non-detection of the take-off weight data entry error. These were the:

  • non-adherence to standard operating procedures
  • first officer reading out the correct weight during the loadsheet confirmation procedure

• first officer amending the take-off weight figure that was recorded on the flight plan to the correct weight, without investigating the discrepancy.

Research into human error has shown that we are capable of making errors across a variety of tasks, and safety investigations aim to identify how such errors remain undetected by a system’s risk controls and/or defences. Errors generally do not occur in isolation and there is usually a series of events/actions that combine within a particular context to produce an error.

In this accident, a series of actions and omissions reduced the effectiveness of the procedural checks and resulted in the crew not detecting the difference between the actual take-off weight and that entered into the EFB.

The first officer’s reported focus of attention to the right of the take-off weight figure, combined with the routine nature of transcribing the value from the EFB onto the flight plan, meant that it was probable he saw the ‘2’ in the place of the ‘3’ but did not detect that it was erroneous. He also reported that while he thought the FLEX temperature appeared to be high, he became distracted and did not investigate this further.

The fact that the values read out by the crew during the pre-departure checks matched the values on the aircraft systems and loadsheet, reduced the chance the crew would detect the error with the EFB entry weight.

The operator’s pre-departure procedures included five checks that were intended to detect take-off weight data entry errors in the performance calculation. Those checks were included in the:

  • Take-off performance error check
  • Take-off data check
  • Loadsheet confirmation procedure.

Take-off performance error check

The take-off performance error check included a check of the data input into the EFB that was performed silently by the captain, and a verbal check by the captain and first officer of the EFB ‘result’ take-off weight against the FMGS INIT B page take-off weight.

As the captain’s EFB input data check did not require verbal crosschecking, the investigation could not determine conclusively from the recorded information whether or not the captain completed that check. Whereas the cockpit voice recorder (CVR) recorded the captain commencing the check after he received the EFB from the first officer, the required verbal comparison between the captain and first officer of the take-off weight in the FMGS INIT B page with the EFB ‘result’ weight did not occur.

That omission might have been explained by the large amount of activity in the cockpit at that time. Research into aural distraction has found that such distraction significantly degrades a person’s ability to apply their full attention to a task, and any distraction of the captain’s attention away from the performance error check increased the risk that it would be missed.

The discussion of an apparently confusing aspect of the planned standard instrument departure (SID) procedure would have added to the workload as the captain checked the EFB and the first officer conducted the pre-departure clearance (PDC) readback. The discussion of the SID may have drawn the captain’s attention to the first officer’s PDC readback, distracting him from checking the EFB input data. That was consistent with the captain’s statement that he ‘copied’ aspects of the PDC from ATC, indicating that his attention was on that communication.

The above distractions may have reduced the captain’s available attentional resources for the take-off performance error check. If the distractions did interrupt that check, the captain may have inadvertently resumed it after the take-off weight verification. He may also have not completed the check after becoming distracted, instead commencing the next action of entering the data into the FMGS, not realising that the take-off performance error check was incomplete.

In turn, the first officer’s attention on the PDC readback may have distracted him from participating in the take-off performance error check. That would explain the recorded gap in the first officer’s involvement until he began assisting the captain with the data entry confirmation.

At the completion of the data entry confirmation, the captain’s action to not transcribe the take-off weight and green dot speed onto his copy of the flight plan and his reading out of the green dot speed in the busy cockpit, negated one of the operator’s defences that might normally have detected the error. The first officer’s likely automated response of ‘checked’ to the captain’s verbalisation of the green dot speed from the EFB was consistent with him not comparing it to the value displayed on the FMGS. The effect of that response may have been to influence the captain to incorrectly accept the different green dot speed during the loadsheet confirmation procedure as this speed had previously been ‘verified’ by the first officer’s response.

The captain’s experience of the reliability of the EFB-derived take-off performance figures may have established an expectation that the results would most likely be correct. In combination with the in-cockpit distractions, that may have reduced the captain’s level of attention to the checking process, thereby reducing its effectiveness.

Although not required by the operator’s procedures, had the augmenting captain the opportunity to perform his own check of the take-off performance calculations, he may have detected the take-off weight entry error.

Take-off data check

The take-off data check was to be carried out following receipt of the final load sheet, and included a requirement for both crew members to silently verify that the take-off weight displayed on the INIT B page was greater than the FLEX-limiting take-off weight previously recorded by the first officer on the master copy of the flight plan.

The take-off data check could be interpreted in two different ways as a result of its wording and sequencing. The use of the term ‘CHECK/REVISE IF REQ’D’ could lead flight crew to think that the check was only required if there was a change to the zero fuel weight (ZFW) on the FMGS INIT B page, as identified by the captain’s review of the loadsheet. Given that the procedure required the take-off performance calculation to be carried out following the receipt of the revised ZFW, it is probable that the take-off weight does not often change from that used in the take-off performance calculation. This would act to reduce the significance of the check, and make it appear to be a superfluous repeat of the take-off performance error check carried out shortly before. On the accident flight the take-off performance calculation was made after the loadsheet had been received and printed.

The lack of a requirement to verbally verify the two take-off weights prevented the investigation from confirming whether this check was carried out by the crew. However, if it was carried out, it was ineffective and neither the captain nor the first officer detected the erroneous take-off weight.

Loadsheet confirmation procedure

The loadsheet confirmation procedure provided the final two procedural defences to detect the error in the take-off weight. The first was when the first officer read out the take-off weight from the FMGS INIT B page and then the ‘result’ take-off weight from the master flight plan.

The first officer read the weight from the INIT B page correctly as 361.9 tonnes, but when he read the value from the master flight plan he read 326.9 tonnes. He was then heard to immediately change this to 362.9 tonnes, even though the value recorded on the master flight plan was 262.9.

It is likely that, having just read the weight as 361.9 tonnes from the INIT B page, and knowing that this was correct, the first officer automatically started to say the ‘three’ (of 362.9) when reading the ‘result’ weight from the master flight plan because this was, logically, the next value. However, on seeing 262.9 he verbalised the value as 326.9, before, upon realising the transposition of the ‘2’ and ‘6’, ‘correcting’ it to 362.9. This was consistent with his understanding of the actual take-off weight. The first officer reported that he changed the number on the flight plan from a ‘2’ to a ‘3’ at this point during the procedure because he thought that he had made a simple transcription error when recording the values from the EFB on the flight plan. Since he believed he had made a simple transcription error, the first officer did not investigate the discrepancy, thereby removing the opportunity to detect the original data entry error in the EFB.

There was no specific requirement for the captain to refer to the ‘result’ weight on his copy of the flight plan. It is reasonable to expect that the captain would only have been comparing the values verbalised by the first officer, and those values satisfied the requirements of the check. That was, the INIT B take-off weight did not exceed the verbalised ‘result’ weight.

The final opportunity for the flight crew to detect the data entry error was the gross error check that compared the green dot speed values obtained from the EFB and FMGS. That check required the captain to compare the green dot speed read out by the first officer from the FMGS PERF TAKEOFF page with that calculated by the EFB and recorded by the captain on his copy of the flight plan. A difference of 3 kts or more indicated a weight input discrepancy and had to be resolved by the crew.

The captain’s hesitation and then non-standard response of ‘yes’ when the first officer read out the value of 265 kts from the FMGS INIT B page suggested that the captain was thinking about the value, rather than directly comparing it to a figure that was written down to confirm its acceptability. At that time, the captain had been crosschecking the first officer’s verbalised figures against the load sheet, and therefore may not have had his transcribed EFB green dot speed readily available for comparison. Instead, the captain may have relied on his recollection of the value calculated by the EFB.

Given that both green dot speeds had the same first and last number (that is ‘2-other value-5’), and the emphasis of the criteria was that the speeds had to be within 2 kts of each other, it is possible that the captain’s attention was drawn to the last digit, as he expected any difference to occur there. Because both numbers ended in a 5, it may have appeared to the captain that the 2 kts criterion was satisfied.

The flight crew’s reported trust in the performance calculation adversely affected their critical analysis of the results obtained. This trust in the standard operating procedures as a defence was likely reinforced by their previous experience of those procedures routinely detecting such errors.

In summary, the crew’s non-detection of the erroneous take-off weight entry in the EFB was multifaceted, and reduced the effectiveness of the procedural checks that could, individually, have detected the error. It is possible for errors to pass undetected through various checks, which is why most procedures incorporate multiple independent checks to verify critical information.

Such errors are not confined to any particular aircraft type, operator or type of operation. It is likely that, given that the current risk controls across operators are procedural in nature, these errors will continue to occur in normal operations throughout the world.

4. Degraded take-off performance not detected

All the calls made, and actions taken by the flight crew were typical of a normal takeoff until the point where the captain called a second time for the first officer to ‘rotate’. There were no indications from the communications or actions in the cockpit that any of the flight crew were aware of, or able to detect, that the aircraft’s performance was insufficient for a safe takeoff. It was not until the aircraft approached the end of the runway, without lifting-off as expected, that the captain realised there was a problem and applied TO/GA thrust.

Flight crew monitoring of take-off performance is based on a set of reference speeds during the take-off roll and does not include the monitoring of the aircraft’s acceleration. Therefore, if the take-off reference speeds are incorrect, or the acceleration insufficient, flight crew have no reliable indication of any problem. Accordingly, it is difficult for crew to identify that take-off performance is degraded. Two items of information are required for flight crew to determine degraded take-off performance:

  • a measure of the aircraft’s actual acceleration, in real time
  • a reference, or expected, level of aircraft acceleration.

There was no indication of the actual aircraft acceleration available to the flight crew on the night of the accident. The only sources of information on the aircraft’s take-off performance were the airspeed indication on the primary flight display, information from the engine instruments, and the pilots’ perception of the acceleration. As previously discussed, airspeed alone provides no indication of acceleration and the engine instruments provide an indication of engine thrust and other parameters. Flight crew have to derive engine- related problems from those parameters. A human’s ability to determine acceleration is neither an accurate nor reliable means to assess take-off performance. Furthermore, that accuracy and reliability is further degraded in darkness.

At the time of the accident, an indication of the expected acceleration was not provided to the crew, nor was it required to be. The take-off performance philosophy was based on the aircraft accelerating at a rate commensurate with the performance calculations.

Without a quantitative method for assessing the actual acceleration attained during the take-off roll, or having a ‘reference’ acceleration to compare with the actual acceleration, the flight crew could only judge the aircraft’s acceleration in comparison with their previous experience. All four flight crew reported that they ‘felt’ that the aircraft’s acceleration was consistent with a ‘heavy’ A340, specifically an A340-313K and were not alerted to the low acceleration.

All four flight crew members had encountered a large variation in take-off performance due to: the use of reduced thrust takeoffs; operating a variety of aircraft with significant differences in take-off weight (due to differing routes and passenger/cargo loads); and differences in runway lengths and ambient conditions. The result was that there was no experience-based acceleration ‘datum’ against which the crew could measure the takeoff. That was consistent with the recorded data, which showed that there was no direct correlation between acceleration and take-off weight. For example, the take-off weight for the previous flight from Auckland to Melbourne was 8% greater than the flight from Melbourne to Auckland, but the acceleration was about 80% lower.

None of the four flight crew members raised any concerns regarding the aircraft’s acceleration during the take-off roll, demonstrating the inherent difficulty in detecting degraded take-off acceleration.

5. Large variations in take-off weight

In the previous 2 months of operations, the flight crew were exposed to take-off weights that varied from about 150 to 370 tonnes. This large variation probably affected the conspicuity of the erroneous first ‘2’ in the take-off weight that was displayed in the EFB as it, in itself, was not abnormal. Both the captain and the first officer had operated the A340-541 with take-off weights in the 200 to 300 tonne range, and observing a take-off weight of 262.9 tonnes would not have been sufficiently conspicuous to alert the crew to the possibility of the data entry error.

The crew’s experiences of differing take-off weights would have been further complicated by their mixed fleet flying. Exposure to large take-off weight ranges makes it difficult for flight crew to form an expected ‘normal’ weight, and has been observed as a factor in other erroneous take-off performance incidents and accidents.

6. Variations in take-off performance parameters

The large variability in take-off performance experienced by the crew over the previous 2 months, and the lack of a simple, effective correlation between the weights and parameters, meant that crews were unable to develop mental models, or ‘ballpark’ figures, to assist them in detecting whether one or more of the parameters in a given set of take-off performance figures were anomalous. This was reflected in the flight crew’s comment that the take-off performance figures had lost significance and had become ‘just numbers’.

To further complicate the situation, all four flight crew had experienced parameters in the A340-541 that were very similar to the erroneous values experienced on the night. As such, the take-off performance figures were not sufficient in themselves to alert the crew to the erroneous take-off weight used to calculate the figures.

Another complicating factor for the crew’s ability to comprehend erroneous parameters was the use of the OPT CONF (optimum configuration) option in the EFB, which selected the high-lift device configuration that gave the lowest take-off speeds. Small changes in ambient conditions could result in a change in the take-off configuration, and associated take-off speeds. That increased the difficulty for flight crews to correlate the parameters, even from an airport from which they commonly operated, such as their home port of Dubai.

The factors affecting the crew’s ability to determine the ‘reasonableness’ of the take-off performance parameters is discussed further in section 6.4.4 of this report, titled Reasonableness self-check.

Emirates A345 (4)

Photo (C) Ronny Busch. Planespotters.net

Risk controls

1. Distraction management

Research on distraction and interruptions has identified their detrimental effect on the formation and detection of errors. The research has also highlighted that the majority of errors occurred during the pre-departure phase of a flight. Thus, it is important to manage distraction during this flight phase to minimise the potential for errors to be formed and not detected until they have effect.

The calculation and checking of the take-off performance was critical to the safety of the flight, yet there was no guidance provided by the operator on the management of distraction during that process. The operator had identified other flight phases as critical to the safety of flight, such as taxi, takeoff and climb, and had a sterile cockpit rule for those phases. There was no such management practice to reduce the potential for distraction during the take-off performance calculation and checking process. Together with the operator’s requirements for its flight crews to cooperate with all other personnel involved in a flight, including ground staff, this increased the risk that flight crew would be distracted by other personnel during those interactions.

The lack of clear direction on the role of, and required input from the augmenting crew during the pre-departure preparation further increased the distraction risk to the operating flight crew. That was consistent with the reports that the presence of augmenting crew in the cockpit during the pre-departure phase created a distraction for the operating crew.

By not including a component on the management of in-cockpit distractions in the operator’s training program, the operator effectively left it to flight crews to develop their own distraction management practices based on their operational experiences and the environment in which they were operating. Without ongoing, formal reinforcement, such as through simulator exercises, it could be expected that the importance placed by crews on distraction management might diminish, potentially increasing their acceptance of continued interruptions from ground crew during the pre-departure phase.

The provision by the operator of briefings to flight crews on distraction management in the months prior to the accident appear to have been ineffective in this accident. Ongoing, formalised training might have alerted the captain to the distraction risk of the non-linear task completion risk represented by his check of the EFB input while the first officer was carrying out an ATC readback.

The prevalence of distraction as a contributor or influence in error development is well documented in human factors research. The challenge for operators is to develop and implement training and standard operating procedures that enable flight crew to manage distractions during safety-critical tasks, especially during the pre-departure phase.

2. Standard operating procedure design/usability

The conduct of the take-off weight comparisons within the takeoff performance error check, take-off data check, and loadsheet confirmation procedure, within a relatively short period of time, may have been perceived by flight crew as redundant. Given that on the accident flight, the take-off performance calculation was based on the final, and therefore unchanging weight figures, the risk that the three, close proximity checks might appear superfluous was heightened. That might explain to some extent why only the final loadsheet confirmation procedure was completed.

Standard operating procedures are typically designed on the basis that information flow into the cockpit is sequential and the procedures are conducted in a linear fashion based on this sequential information flow. Research has shown that the information flow into the cockpit during line operations typically does not follow the sequence upon which the procedures are based. This increases the likelihood that, following a distraction, the flight crew will re-enter a procedure at an incorrect point. The sequence of delivery of information may also lead the crew to believe that a check is no longer required.

The reported normal practice for flight crew to add 1,000 kg to the take-off weight in an A340-541 before it was entered into the EFB, to allow for last minute changes to the load, appears to be a strategy used by flight crew to avoid having to recalculate the EFB figures in the likely event the final weight figures differed to those initially used. It is probable this strategy developed from the regularity of last minute changes, and 1,000 kg covered all possible changes that did not require the issue of a new loadsheet.

3. Documentation design

Given the captain’s deviation from the requirement to record the green dot speed on his copy of the flight plan, and the wide variation noted in the documentation obtained for the preceding 2-month period, it seems likely that the lack of a specific position on the flight plan for recording the green dot speed led crew members to develop their own method for recording it.

While these individual methods did not strictly comply with standard operating procedures, they did comply with the intent, which was to note the speed in order to conduct a subsequent comparison during the load sheet confirmation procedure. However, the variation by crews in recording the green dot speed, and therefore lack of a consistent and predictable information source, increased the risk that any EFB data entry errors would remain undetected.

4. Reasonableness self-check

A number of factors influenced the flight crew’s ability to determine the ‘reasonableness’ of the take-off performance figures calculated by the EFB. One of the main factors was the variation of those parameters as experienced by the flight crew during normal operations. The normalcy of that variation in parameters increased the difficulty for flight crew to recognise inappropriate outputs from the EFB. The reasons for this variation have been discussed previously.

This problem is not unique to this accident. Previous investigations into similar data entry error and tailstrike occurrences have highlighted the inability of flight crew to conduct a ‘rule of thumb’ or reasonableness check of speeds when moving between aircraft types. Furthermore, an unintended consequence of mixed fleet flying appears to be a reduction in a flight crew’s ability to build a model in long-term memory to facilitate recognition of ‘orders of magnitude’, or a ‘rule of thumb’, in respect of take-off performance data. Because the figures that are quite reasonable for one variant may not be reasonable for another variant, the flight crew would need to build a model for each variant that they operate.

There was no specific guidance in the regulatory or operator’s documentation to assist flight crew in forming appropriate mental models regarding the weight and corresponding take-off performance parameters for a particular flight.

Other safety factors

1. Electronic flight bag/operational procedures ergonomics

An ergonomic review of the EFB was carried out to determine the current and optimal flows of information into, and out of the EFB in the context of the operator’s procedures.

This included a review of the flow of information into the EFB, from the EFB to the flight plan, from the EFB to the FMGS, and from the FMGS to the final check against the flight plan. Figure 36 shows the link analysis for the flow of information from the EFB to the FMGS and then to the flight plan for the final check.

The analysis found the flow of information into the EFB and onto the flight plan was clear and simple. Because the EFB and flight plan mirrored each other with regard to the layout of information, the flow was easy to follow and sequential.

The analysis of the information flow from the EFB to the FMGS MCDU revealed a different situation. It was more complicated, less sequential, and required the focus of the user’s attention to move around the screen. The checking process, which required flight crew to verify information from the FMGS against the flight plan, was more difficult because the values were not printed on the flight plan in the same sequence in which they were read out from the FMGS. Although this did not occur on the accident flight, this complexity increased the risk of errors in data entry and checking.

In addition to the flow of information, a number of other issues were highlighted. The first related to the inconsistency in the weights entered into the EFB and recorded on the flight plan, which varied between tonnes and kilograms. The possibility of transposition errors would be reduced if the units were consistent.

The second issue was related to the initial entry of data into the EFB. The EFB required the user to enter the take-off weight and not the individual ZFW and fuel load figures. The previous incidents highlighted the number of times that the zero fuel weight was entered into the EFB instead of the take-off weight. If the user was required to enter the ZFW, the fuel weight and the take-off weight, the EFB could perform an independent check of the figures to reduce the likelihood of a data entry error.

The final issue related to last-minute changes. To minimise the possibility of conducting last-minute recalculations of take-off performance parameters, it was common practice for users to enter a take-off weight that included an additional weight to account for the maximum permissible last minute change. This created a potential problem because, by adding this margin the flight crew could, inadvertently, enter an incorrect take-off weight into the EFB, or be less likely to identify an error in a weight value entered into the EFB because the original value had been deliberately altered during entry.

Other information

1. Fatigue

Consistent with the results from the operator’s examination of the operating crew’s fatigue, the location of both operational crew members’ effectiveness towards the top of the Fatigue Avoidance Scheduling Tool effectiveness range indicated that they were not significantly impaired by fatigue at the time of the accident. That assessment was also supported by the crew providing data that indicated they both had probably obtained sufficient rest during their layover in Melbourne. The layover time was greater than 36 hours and the captain and first officer reported that they did not feel unusually fatigued when they commenced their duty period. Moreover, there was no sound on the CVR of any crewmember yawning, and no prolonged silence or disengagement of crew from conversations (other than when necessary for operational reasons) that might be linked with crew fatigue.

The investigation determined that it was unlikely the operating flight crews’ performance was impaired by fatigue at the time of the accident.

Summary

There were a number of similarities between the circumstances of this accident and other erroneous take-off performance data-related occurrences. In all cases examined, it was found that the manner in which the errors occurred, and went undetected were varied and was not particular to any aircraft type, operator, or procedure. However, there were two core factors that all the occurrences had in common:

  • individual actions rendered operator’s procedures and controls ineffective
  • degraded take-off performance remained undetected until very late in the take-off roll, if at all, as there was no specific requirement or system for monitoring an aircraft’s acceleration.

A number of safety recommendations have been made by several investigation agencies regarding automated take-off performance monitoring to assist flight crews during the take-off roll.

FINDINGS

Context

From the evidence available, the following findings are made with respect to the tailstrike and runway overrun at Melbourne Airport, Victoria on 20 March 2009 that involved Airbus A340-541, registered A6-ERG and should not be read as apportioning blame or liability to any particular organisation or individual.

Although there are a number of factors identified directly relating to this accident, the accident needs to be taken in the context of the long history of similar take-off performance events identified by this investigation. Even though the events leading to this accident may be particular to this case, the previous events highlight that there are a multitude of ways to arrive at the same situation, placing the aircraft and passengers in an unsafe situation before the aircraft has even been pushed back from the terminal. The preferred safety actions will be those that address the whole situation, not just those that address the specific factors identified in this accident.

Contributing safety factors

  • The first officer inadvertently entered the incorrect take-off weight into the electronic flight bag to calculate the take-off performance parameters for the flight.
  • The captain was distracted while checking the take-off performance figures in the electronic flight bag, which resulted in him not detecting the incorrect take-off weight.
  • During the pre-departure phase, the flight crew did not complete all of the tasks in the standard operating procedures, which contributed to them not detecting the error.
  • When conducting the loadsheet confirmation procedure, the first officer called out 362.9 tonnes as the FLEX take-off weight, rather than the 262.9 tonnes that was recorded on the master flight plan, which removed an opportunity for the captain to detect the error.
  • The first officer changed the first digit of the FLEX take-off weight on the master flight plan during the loadsheet confirmation procedure, believing it had been transcribed incorrectly, which removed an opportunity for the flight crew to detect the error.
  • The lack of a designated position in the pre-flight documentation to record the green dot speed precipitated a number of informal methods of recording that value, lessening the effectiveness of the green dot check within the loadsheet confirmation procedure. [Minor safety issue]
  • The flight crew’s mixed fleet flying routinely exposed them to large variations in take-off weights and take-off performance parameters, which adversely influenced their ability to form an expectation of the ‘reasonableness’ of the calculated take-off performance parameters.
  • The operator’s training and processes in place to enable flight crew to manage distractions during the pre-departure phase did not minimise the effect of distraction during safety critical tasks. [Significant safety issue]
  • The rotation manoeuvre was commenced at an airspeed that was too low to permit the aircraft to become airborne but sufficient to overpitch the aircraft, resulting in the tailstrike.
  • The application of the calculated (high) FLEX temperature during a reduced thrust take-off led to a reduced acceleration, an extended take-off roll, and the subsequent runway overrun.
  • The flight crew did not detect the reduced acceleration until approaching the end of the runway due to limitations in human perception of acceleration, which was further degraded by reduced visual cues during a night takeoff.
  • The existing take-off certification standards, which were based on the attainment of the take-off reference speeds, and flight crew training that was based on the monitoring of and responding to those speeds, did not provide crews with a means to detect degraded take-off acceleration. [Significant safety issue]

Other safety factors

  • The design of the flow of information from the electronic flight bag into the aircraft systems and flight documentation was complex, increasing the potential for error.
  • The available Cross Crew Qualification and Mixed Fleet Flying guidance did not address how flight crew might form an expectation, or conduct a ‘reasonableness’ check of the speed/weight relationship for their aircraft during takeoff. [Significant safety issue]
  • The failure of the digital flight data recorder (DFDR) rack during the tailstrike prevented the DFDR from recording subsequent flight parameters. [Minor safety issue]

Other key findings

  • It was unlikely the operating flight crew were unduly affected by fatigue.
  • The captain’s selection of Take-off/Go-Around (TO/GA) thrust during the rotation manoeuvre very likely limited the adverse consequences of the runway overrun.
  • The inability of the cabin crew member at door R2 to reach the interphone handset that was located at seat R2A degraded the flow of communication between cabin crew members.

SAFETY ACTIONS

As a result of the accident, the operator and aircraft manufacturer have taken a number of safety actions. In addition, the Australian Transport Safety Bureau (ATSB) has issued a safety recommendation to the United States Federal Aviation Administration and a safety advisory notice to the International Air Transport Association and the Flight Safety Foundation in an effort to minimise the likelihood of future similar events.

REFERENCES

Excerpted from Tailstrike and runway overrun – Melbourne Airport, Victoria –20 March 2009 – A6-ERG, Airbus A340-541, Australian Transport Safety Bureau final report

FURTHER READING

  1. When the error comes from an expert: The Limits of Expertise
  2. Multitasking in Complex Operations, a real danger
  3. The Organizational Influences behind the aviation accidents & incidents
  4. Pilot performance in emergencies: why can be so easy, even for experts, to fail

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Last week, on Apri 25th, 2017, the BEA announced opening investigation on an Air France A343 abnormally long takeoff at Bogota (SKBO-BOG) which has been classified as a serious incident. That incident reminded some of us of this accident.

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minime2By Laura Victoria Duque Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

 

MyCargo B744 fatal accident at Kyrgyz Republic, Jan 16th, 2017. Preliminary Report

Interim report released on 24th March 2017.

My Cargo 1

Photo TC-MCL, B747-412F, Manufactured on February 2003

INTERSTATE AVIATION COMMITTEE. AIR ACCIDENT INVESTIGATION COMMISSION

PRELIMINARY REPORT

Fatal accident

Boeing 747-412F, registration TC-MCL

Near Manas International Airport, Bishkek, Kyrgyz Republic

16.01.2017, 07:17 local time (01:17 UTC), nighttime

Factual Information

History of Flight

The intended flight route was from Chek Lap Kok Airport (VHHH, Hong Kong) via Manas International Airport (UCFM, Bishkek) to Ataturk Airport (LTBA, Istanbul)

The calculated aircraft Take Off Weight- TOW was about 342500 kg, with CG of 23% MAC. The a/c departed from Hong Kong at approximately 19:12 1 on 15.01.2017. At 19:37 the a/c reached FL 320. Further, starting at 20:43 FL 340 was maintained. The flight was conducted in autoflight mode.

Before descending the crew conducted a low visibility approach and landing briefing. The ILS (111.7 MHz) and VOR/DME MNS (113.4 MHz) frequencies for RWY 26 approach were tuned.

At 00:41 on 16.01.2017 the aircraft – a/c entered Bishkek Area Control FIR. At 00:51 the crew reported they were ready for the descent. The controller cleared descent to FL 220. The descent from cruise flight level was initiated at approximately 00:52 at distance of 130 nm from VOR/DME MNS (Here in after unless otherwise stated reference is made to distances from VOR/DME MANAS that is installed 0.8 nm before RWY 26 end in direction open to landing course).

FL 220 was reached at approximately 00:59.

At 01:03:10 the crew requested further descent. The controller cleared descent to FL 180 to RAXAT reporting point.

My Cargo fig 3

At 01:05:55 the a/c reached FL 180. When overflying RAXAT the a/c was at that flight level.

At 01:06:02 the crew was handed over to Approach Control.

After the a/c overflew RAXAT the controller cleared further descent to FL 060 as per TOKPA 1 STAR.

Descent from FL 180 was initiated at 01:06:40 (a moment when the Auto Pilot – A/P FLIGHT LEVEL CHANGE mode was engaged). At its initial stage, the crew used FLIGHT LEVEL CHANGE A/P mode longitudinally, while laterally LATERAL NAVIGATION mode was used. During the descent, the crew also used V/S mode. Engines operational mode was close to flight idle. Within 01:09:18 to 01:14:32 (FL 123 to FL 044) the crew extended spoilers manually.

TOKPA reporting point over flight occurred at 01:11:18. The a/c was crossing FL 092 while in descent. According to the approach chart, FL 060 or above should be reached when overflying TOKPA.

At 01:11:55 the controller informed the crew on transition level (FL 060), QNH (1023 hPa) and cleared them for ILS approach to RWY 26.

At 01:12:00 the crew set QNH.

At 01:12:07 at a speed3 of 250 kt and distance of 12.5 nm the flap handle was set to 1º

At 01:12:42 the controller cleared the crew for the further descent to altitude 3400 ft. The a/c was meanwhile crossing FL 074 (Hereinafter unless otherwise stated QNH altitude is referred to)

The CVR record of cockpit communications shows that at that stage of flight the crew was monitoring the flight altitude and was aware they were higher than the STAR chart.

At 01:12:51 at a speed of 240 kt and distance of 9.8 nm the crew started extending flaps to 5º. A bit later the crew identified the ILS three-letter identifier (India Bravo Kilo) for RWY 26.

At 01:13:35 at a speed of 220 kt and distance of 7.2 nm the flap handle was set to 10º.

At 01:14:05 the Digital Flight Data Recorder – DFDR recorded LOC (Localizer) capture (Figure 1) and start of localizer establishing maneuver. At that time the a/c was at a distance of about 6 nm in descent at an altitude of 5655 ft (Height: 3600 ft)

My Cargo fig 1'Figure from Interstate Aviation Committee Air Accident Investigation Commission Preliminary Report

Since 01:14:08 the three A/Ps were engaged. Autoflight was continued, LOC MODE engaged laterally and FLIGHT LEVEL CHANGE was active vertically. 3400 ft was selected as target altitude (glideslope capture altitude). As per the approach chart, this altitude shall be reached at a distance of 5.4 nm and maintained until 3.2 nm (glideslope capture).

My Cargo fig 4

At 01:14:26 at a speed of 190 kt and distance of 4.5 nm the flap handle was set to 20º.

A bit earlier, at 01:14:18 the crew initiated landing gear extension.

The final approach point for RWY 26 is at a distance of 3.2 nm. At this distance, the a/c was in descent, crossing 4000 ft.

At 01:15:03 at a speed of 190 kt and distance of 2.7 nm the flaps were set to 25º.

At 01:15:21 after the crew confirmed capturing the localizer, the a/c was handed over to Tower Control.

At 01:15:25 at a distance of 1.7 nm the a/c reached 3400 ft and ALT HOLD OPER A/P mode was engaged longitudinally.

Since that time the flight was performed at a constant altitude along the RWY 26 landing course. The a/c was significantly higher than the glideslope, the glideslope pointer was in full down position. The glideslope mode was armed (G/S MODE ARM), but the glideslope was not captured.

At 01:15:31 while the a/c was in level flight at 3400 ft LOM (Locator, Outer Marker) overflight was recorded (as per the approach chart LOM overflight altitude is 2800 ft). The CVR record contained no aural signal of LOM overflight. However, the LOM is indicated to both crew members on the PFD.

01:15:38 the controller informed the crew on the weather (wind calm, RVR: 400 m (threshold), 325 m (midpoint), 400 m (end), vertical visibility 160 ft) and cleared them for landing. RWY 26 is certified for ICAO CAT II operations.

At 01:15:50 at a speed of 175 kt and distance of 0.3 nm the flap handle was set to 30º.

A glideslope signal was captured at 01:15:52, at that time the a/c was almost over VOR/DME MANAS at a distance of approximately 1.1 nm from RWY 26 threshold, at an angle of approximately 9º (Figure 1). However, as per the approach chart, the rated glideslope angle is 3º (figure 4)

The a/c automatically initiated descent with a vertical speed of up to 1425 ft/min.

6 seconds after the glideslope capture LAND 3 autoland status annunciation was recorded. The crew called out the annunciation.

At 01:16:01 at 3300 ft LMM (Locator, Medium Marker)overflight was recorded (as per the approach chart LMM overflight altitude is 2290 ft). The CVR record contained no aural signal of LMM overflight. However, the LMM is indicated to both crew members on the PFD.

After the glideslope descent was initiated the glideslope pointer was fluctuating within – 4 to + 4 dots.

At 01:16:07, 15 seconds after the glideslope was captured, at 3150 ft AP CAUTION and FMA FAULT 2 events (See Section 1.18.1) were recorded. These events were continuously recorded almost until the end of the flight (until the FLARE A/P mode activation).

The descent was performed at approximately 160 kt CAS. The landing weight was about 274800 kg. MAP mode was selected on both pilots’ navigation displays with a scale range of 10 nm.

As the a/c was descending LAND 3 status degraded to LAND 2, which was confirmed by the crew callout.

Within 01:16:49 – 01:16:56 the EGPWS Mode 5 GLIDESLOPE alert was triggered 5 times (See Section 1.18.2). Further, the EGPWS system only provided information on reaching selected approach altitudes and minima.

At 01:17:04 the crew crossed RWY 26 departure end at a height of about 110 ft. At 01:17:05 EGPWS 100 ft radio altitude voice callout occurred while the decision height was 99 ft.

At 01:17:07 the FO called “Minimums”.

At 01:17:08 the PIC informed that there was no visual contact («NEGATIVE») and called to go-around.

At 01:17:09 A/P Flare mode was engaged and half a second later at 58 ft radar altitude TOGA switch was pushed as per the DFDR.

The Go-Around mode activation resulted in engine power increase, vertical acceleration of about 1.4 g and arresting descent. 3.5 seconds after the TOGA switch had been pushed the a/c hit slightly upsloping terrain and obstacles. The ground speed at the time of impact was 165 kt. The maximum recorded vertical acceleration was 6 g.

Initial impact occurred at a distance of approximately 930 m from RWY 26 departure end. The collision with terrain and obstacles resulted in hull loss, most of the a/c structure was consumed by the post-crash fire.

Injuries to Persons

My Cargo table 1

Others: Injured and killed persons on the ground. Table from Interstate Aviation Committee Air Accident Investigation Commission Preliminary Report

Damage to Aircraft

The a/c was totally destroyed and partly consumed by the post-impact fire.

Other Damage

According to the information provided by the Ministry of Internal Affairs of Kyrgyz Republic, 38 buildings in the settlement were broken, including 19 dwelling houses and 12 household outbuildings totally ruined and 7 dwelling houses partly broken.

Personnel Information

1. Flight Crew

Pilot-in-command

Date of birth: 10.11.1958

Total flight hours: 10808 h

Flight hours on B 747: 820 h

Flight hours on B 747 as PIC: 820 h

Flight hours over last month: 39 h 36 min

Flight hours over last 3 days: 06 h 04 min

Flight hours on accident day: 06 h 01 min

Total duty time on accident day: 09 h 10 min

First Officer

Date of birth: 01.01.1958

Total flight hours: 5894 h

Flight hours on B 747: 1758 h

Flight hours over last month: 32 h 33 min

Flight hours over last 3 days: 08 h 51 min

Flight hours on accident day: 06 h 01 min

Total duty time on accident day: 09 h 10 min

2. Air Traffic Control

Senior Controller (at Approach Control working station at the time of the accident)

Date of birth: 12.03.1980

Experience as air traffic controller: Since 2000

Authorizations: Ground Control, Tower Control, Approach Control, Upper Airspace Area Control

ATC Controller (at Tower Control working station at the time of the accident)

Date of birth: 06.07.1959

Experience as air traffic controller: Since Since 1992

Authorizations: Ground Control and Tower Control

Meteorological Information

At the time of the accident weather forecast for 00:00 on 16.01.2017 to 24:00 on 16.01.2017 was current for Manas Airport

TAF forecast for Manas Airport Issued on 15.01.2017, at 22:44, valid from 00:00 on 16.01.2017 to 24:00 on 16.01.2017:

Surface wind 240º – 4 mps, visibility 0200 freezing fog, vertical visibility 030 m, TEMPO from 00:00 on 16.01.2017 till 06:00 on 16.01.2017 wind 120 – 5 mps, visibility 0800 m, freezing fog smoke, vertical visibility 090 m, from 06:00 on 16.01.2017 surface wind 320 – 04 mps, visibility 1500 m, mist, clouds broken at 150 m, TEMPO from 06:00 on 16.01.2017 to 12:00 on 16.01.2017 visibility 0800 m, freezing fog, clouds few at 090 m.

Regular weather report for Manas Airport was broadcast via a VHF channel for 01:00 on 16.01.2017 in Russian and English:

Manas weather 01:00 surface wind calm, at 100 ft wind 110 degrees 01 mps, visibility 50 m RVR 300 m, freezing fog, vertical visibility 100 ft, temperature minus 09С, dewpoint minus 10ºС, QNH 1023 hPa, course 255, runway damp, braking action 0.6, NOSIG.

Actual weather at Manas Airport for runway course 255° at the time of the accident was as follows:

For 01:16: wind 60 degrees 01 mps, visibility: runway threshold 100/RVR 400 m, runway midpoint 100/RVR 350 m, runway end 100/RVR 400 m, vertical visibility 050 m, temperature minus 09°С, dewpoint minus 10°С, QNH 1023,9 hPa, RWY 26 damp, braking action 0.6, TREND NOSIG.

Aids to Navigation, Landing and ATC

Below is a list of ground navigation equipment supporting approach to landing for RWY 26:

– MSSR (Monopulse Secondary Surveillance Radar);

– ILS NM-7000 (111.7 MHz, IBK);

– VOR/DME (113.4 MHz, MNS);

– PAR-10C LMM (481 kHz);

– PAR-10C LOM (975 kHz).

The peculiarity of Manas International Airport is that ILS systems on both courses have the same frequency (111.7 MHz) while their letter identifiers are different. Based on the available information the system is configured in such a way that when the ILS for one course is engaged, the ILS for the other course is automatically disengaged.

Airdrome Information

Manas Airport is 23 km to the north of Bishkek. Manas Airdrome with RWY 08/26 equipped for precise ICAO CAT II approaches holds Certificate of Airdrome Conformity.

The airdrome has one runway, 4204 m long and 55 m wide. Airdrome designation – 4 E The runway has 4.5 m wide perimeter pavement along its entire length (concrete for 2.5 m, asphalt- concrete for 2 m) on each side of the runway.

Runway surface is 40 cm thick fibercrete.

Runway longitudinal slope is 0.0026 (0.26%). There are no longitudinal slope changes of more than 1.5%.

ARP elevation – 2080 ft (634 m). Threshold elevation: RWY 08 – 2090 ft (637 m); RWY 26 – 2055 ft (626 m).

The airstrip is 4324 m long and 300 m wide. The clearway measurements are as follows: RWY 08 – 400х300 m; RWY 26 – 250х300 m, surface type – ground.

There are ground runway end safety areas for RWYs 08/26 measured 240х110 m.

Manas Airdrome is limited by concrete and metal net fencing, along its entire perimeter.

Beyond the airdrome, at a distance of about 1000 m from the threshold of RWY 08 there are dwelling houses and outbuildings of Dacha-SU settlement, their height not exceeding the pertinent limitations.

Wreckage Information

The airframe was broken into multiple pieces, the largest of them being located within the last third of the wreckage path. The overview of the debris field is shown in

My Cargo fig 5

My Cargo fig 6 

Photos from Interstate Aviation Committee Air Accident Investigation Commission Preliminary Report

There are no signs of fire or thermal impact on the pieces of fuselage, wing and engines located before the fire cell, either on the outside or on the inside. Beyond the debris field no airframe parts were found (fuselage, wing, empennage, etc.)

The vertical fin and horizontal stabilizers (Figure 7) remained attached to the tail part of the fuselage (pressure dome to the APU exhaust). Their final position was inverted. There were no signs of fire or soot on the fin.

My Cargo fig 7

Photo from Interstate Aviation Committee Air Accident Investigation Commission Preliminary Report

The horizontal stabilizer’s center section, trim actuator and ball screw showed no external damage.

At the time of the accident, the wing flight control surfaces were consistent with the landing configuration. It was confirmed by the position of the leading and trailing edge flaps – all the way to the wing final stop.

Spoilers actuators with fragments of control surfaces were found, their position showing that at the time of the accident the spoilers were retracted (actuator drive cylinders pilled in).

The external examination of the cockpit revealed both pilots’ control columns bearing no external damage.

The elevators remained installed on the aircraft consistent with a pitch-up position. The mechanical coupling between the elevators and servo tabs was intact.

The Left-Hand aileron was torn. The Right-Hand aileron was broken into pieces. It was not possible to determine the aileron position at the time of the impact.

The pilots’ pedals had no external damage. The rudder consisting of two halves was not broken. It was not possible to determine the rudder position at the time of the impact.

There are no signs of liquid spillage or kinematics disconnect. The deformation and damage to the control cables, ducts and cords is consistent with the deformation and damage to the tail fuselage

Medical and Pathological Information

The investigation team is awaiting the results of the forensic examination of the persons killed in the accident.

Tests and Research

On 16.01.2017 the quality control laboratory of fuels and lubricants (Manas Airport) examined fuel samples drained from the LH wing (Sampling Act № 1-2 as of 16.01.2016). Based on its results it was concluded that the fuel met the pertinent specifications.

The Flight Control Computer recovered from the accident site has been sent to the NTSB in Washington DC, USA, for specific examinations.

An inspection flight of Manas ILS has been performed as per a specifically designed program coordinated with all participating States

Organizational and Management Information

Being analyzed.

Additional Information

1FMA FAULT 2

As per the Boeing Company explanation, FMA FAULT 2 record means that the AFDS identified pitch mode failure that is the a/c could no longer be tracking the glideslope beam (see FCT 747 Pages 5.19 – 5.20).The mode failure results in the following:

– the pitch flight director bars are removed from the Primary Flight Displays –PFDs

– a yellow line is displayed through the G/S mode annunciation on the PFDs (FMA-Flight mode Annunciator);

– both MASTER CAUTION lights are illuminated;

– a MASTER CAUTION aural is activated;

– an amber AUTOPILOT caution message is annunciated on EICAS –Engine Indication and Cree Alerting System.

Meanwhile, the A/P will not disengage. In the pitch channel, the A/P will maintain an inertial path which tracks a 3º glideslope regardless of the actual glideslope angle at a certain airdrome. The path will be maintained until a valid glideslope signal is regained or until the crew intervenes by disengaging the A/P or initiating a go-around (TOGA switch pushed).Without crew intervention, the A/P will maintain the inertial path until the FLARE mode is engaged. The Autoland status LAND 3 (or LAND 2) will also continue being annunciated. According to the manufacturer’s information, the inertial path generation is a feature in Boeing airplane models 737, 747-400/-8, 757, 767, 777, 787 that allows the A/P to continue the approach for disruptions of either G/S or LOC ground station signals.

2. “GLIDESLOPE” alert (EGPWS Mode 5)

According to the EGPWS Manufacturer’s Pilot Guide, below 1000 ft radio altitude, a deviation of 1.3 dots below the glideslope will trigger a ‘soft’ alert with a caution light and an aural GLIDESLOPE alert at 20% of full volume. Once below 300 ft radio altitude, a deviation of 2.0 dots below the glideslope beam will trigger a ‘hard’ alert with the aural alert sounding repeatedly at full volume

Safety Recommendations

  1. It is recommended that the crews pay attention to following approach charts, monitoring distance and altitude during reference points (FAF, LOM, LMM) overflight when conducting ILS approaches, especially ICAO CAT II and CAT III approaches.
  2. . It is recommended that flight crews be informed that in case ground references are not visible, go-around shall be initiated not lower than the established decision height.
  3. . It is recommended that air traffic controllers, in case they have pertinent equipment available, inform flight crews on significant altitude deviations from that established by the approach charts, especially for ICAO CAT II and CAT III approaches and Low Visibility Procedures, therefore, introducing respective amendments to the procedures and job description of air traffic control personnel should be considered.
  4. It is recommended that top management of airlines operating Boeing aircraft (all models) arrange theoretical and practical (if needed) training to cover awareness, procedures and aspects of flight operations when A/P switches to inertial mode during glideslope descent. Consider the applicability of this recommendation to aircraft of other manufacturers.
  5. It is recommended that the FAA in cooperation with the Boeing Company consider the practicability of changing the A/P logic to prevent occurrences of following inertial glideslope descent (in LAND 3 or LAND 2 mode) in cases when approach path does not allow landing in the appropriate area on the runway. It is recommended that other certification authorities and aircraft manufacturers consider the applicability of this recommendation taking into account actual A/P algorithms
  6. It is recommended that airport administrations analyze the acceptability of constructions in the immediate vicinity of airdromes and, in case findings are raised, take appropriate decisions in cooperation with pertinent authorities.

Excerpted from Межгосударственный авиационный комитет (МАК) – Interstate Aviation Committee Air Accident Investigation Commission (IAC), Interim Report

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minime2By Laura Victoria Duque Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

 

 

 

Comair B734 left main gear collapse on landing on 26 October 2015. Final report

A too high flare in an attempt of a smooth landing led to unstable approach, some maintenance issues found as contributing factors to the main landing gear shimmy. Final report released 27th February 2017

Comair 1 (2)

Photo: South African Civil Aviation Authority Final Report

South African Civil Aviation Authority Accident and Incident Investigations Division

AIRCRAFT ACCIDENT REPORT

Name of Owner: Comair Limited

Name of Operator: Comair Limited

Manufacturer: Boeing Aircraft Company

Model: 737-400

Nationality: South African

Registration Marks: ZS-OAA

Place: O.R. Tambo International Aerodrome

Date: 26 October 2015

Time: 0954Z

All times given in this report are Co-ordinated Universal Time (UTC) and will be denoted by (Z). South African Standard Time is UTC plus 2 hours.

1. FACTUAL INFORMATION

History of flight

The aircraft Boeing 737-400, operated by Comair, flight number BA6234, was on a scheduled domestic flight operated under the provisions of Part 121 of the Civil Aviation Regulations (CARs). The aircraft was on the third leg for the day, after it had performed two uneventful legs. According to their recorded flight plan, the first leg departed from King Shaka International Airport (FALE) to O.R. Tambo International Airport (FAOR), the second leg was from FAOR to Port Elizabeth International Airport (FAPE) on the same day, during which the Captain was flying. During this third leg, the aircraft departed from FAPE at 0820Z on an instrument flight plan rule for FAOR. On board were six (6) crew members, ninety-four (94) passengers and two (2) live animals.

The departure from FAPE was uneventful, whereby the first officer (FO) was the flying pilot (FP) for this leg. During the approach to FAOR, the aircraft was cleared for landing on runway 03R. The accident occurred at approximately 1 km past the threshold. The crew stated that a few seconds after a successful touchdown, they felt the aircraft vibrating, during which they applied brakes and deployed the reverse thrust. The vibration was followed by the aircraft rolling slightly low to the left. It later came to a full stop slightly left of the runway centre line, resting on its right main landing gear and the number one engine, with the nose landing gear in the air.

The crash alarm was activated by the FAOR Air Traffic Controller (ATC). The Airport Rescue and Fire Fighting (ARFF) personnel responded swiftly to the scene of the accident. The accident site was then secured with all relevant procedures put in place. The aircraft sustained substantial damage as the number one engine scraped along the runway surface when the landing gear detached from the fuselage. ARFF personnel had to prevent an engine fire in which they saw smoke as a result of runway contact. The occupants were allowed to disembark from the aircraft via the left aft door due to the attitude in which the aircraft came to rest.

The accident occurred during daylight meteorological conditions on Runway 03R at O.R. Tambo International Airport (FAOR)

Injuries to persons

None of the aircraft occupants sustained any injuries. Two live animals were also accounted for and no injuries were noticed on either of the animals.

Damage to aircraft

The aircraft sustained substantial damage to the No. 1 engine as the engine scraped along the runway surface after the landing gear detached from the aircraft structure.

At the time the landing gear was detaching from the aircraft mountings, more damage was caused to the landing gear mounting points and mechanisms, including flaps fairings, wing root attachment fairings and the landing gear extension/retraction link (lower torsion links and shimmy damper assembly).

Other damage

Runway surface damage was caused by the landing gear during the accident sequence. There was also fuel and hydraulic fluid spillage. The runway was closed until the aircraft was recovered and all the runway surface repairs were completed.

Personnel information

Pilot-in-command (PIC)

Comair 2

First Officer (F/O)

Comair 3

Meteorological information

Meteorological information as obtained from the South African weather service website:

Comair 4

Aerodrome information

The aircraft landed on runway 03R at O.R. Tambo International Aerodrome.

Comair 5

Flight recorders

The aircraft is equipped with a flight data recorder (FDR) and a cockpit voice recorder (CVR). Both these units were removed from the aircraft for further investigation.

The aircraft was also equipped with a quick access recorder (QAR). This device records the same data as the FDR.

FDR Data Analysis

Time history plots of the pertinent longitudinal and lateral-directional parameters are attached as Figures 1 through 4 on Annex B in the full final report. The FDR data show the airplane on a flaps 30 manual approach at approximately 1000 feet radio altitude with the speed brake handle in the armed detent. Tambo International Airport is situated 5558 feet above sea level, and the pressure altitude of the airport at the time of landing was approximately 5100 feet. A combination of latitude/longitude data, Instrument Landing System (ILS) frequency and magnetic heading data indicate the airplane was positioned to land on Runway 03R. The winds were out of the south-southwest at approximately 5 knots, increasing to close to 15 knots prior to touchdown. This resulted in a predominant tailwind component (runway magnetic heading = 34 degrees).

The landing reference speed (VREF) for the airplane’s configuration was 133 knots. Below 1000 feet radio altitude, computed airspeed was 148 knots (VREF+15), on average, and reached as high as 154 knots (VREF+21) prior to flare. High rate column and control wheel inputs were observed during the approach, resulting in a fluctuating pitch attitude and bank angle, respectively. The fluctuations in pitch attitude contributed to variations in calculated vertical speed (relative to the center of gravity [CG]) between -500 and -1500 feet/minute. Furthermore, the airplane was consistently above the glide path, as evidenced by glideslope deviation. The autopilot pitch mode and roll mode were engaged in Glideslope and Very High Frequency (VHF) Omnidirectional Range (VOR)/Localizer mode, respectively, indicating Flight Director (FD) guidance (FD switches were), relative to glideslope and localizer deviation, was available to the crew.

Flare was initiated with a nose-up column input at approximately time 4767 seconds at a radio altitude of around 65 feet. The throttles reached forward idle (0 degrees throttle lever angle [TLA]) by time 4771 seconds. The calculated vertical speed became positive momentarily around time 4772 seconds, as the airplane floated prior to touchdown. The airplane was experiencing an approximate 10-knot tailwind below 100 feet radio altitude. Touchdown occurred at time 4776 seconds at a computed airspeed of 139 knots (VREF+6) and a ground speed of 167 knots. The airplane had an approximate 2-3 degree left bank angle and a 1-degree right drift angle (ground track right of heading) at touchdown. The calculated sink rate (negative vertical speed) at touchdown was around 1.8 feet/second with a normal load factor of approximately 1.1 Gs.

The closure rate at touchdown was approximately 3 feet/second. Closure rate is the rate of change of distance between the landing gear and the local terrain and is generated by calculating the sink rate of the main landing gear and accounting for any runway slope near the point of touchdown (based on Jeppesen runway information). The effect of an upsloping (positive) runway would increase the closure rate of the main landing gear with the runway compared to the airplane sink rate at the CG. Conversely, the effect of a downsloping (negative) runway would decrease the closure rate of the main landing gear with the runway compared to the airplane sink rate at the CG. In addition, the effect of a roll rate at touchdown would increase the main landing gear closure rate on the down-wing side. The runway slope for Runway 03R is 0.52%.

Following touchdown, the speed brakes automatically deployed and wheel braking was applied, although it was unclear whether it was due to manual or autobrake application. Thrust reversers were commanded approximately 4 seconds after touchdown. Around this same time, as de-rotation completed, the left main gear collapsed, as evidenced by a rapid increase in bank angle to the left and a momentary increase in pitch attitude. Spikes were observed in both longitudinal acceleration and normal load factor, and lateral acceleration shifted significantly to the right. The left wing trailing edge flap measurement also indicated a lower flap setting than the right after time 4782 seconds. As the landing rollout continued, the crew commanded right control wheel and right rudder (note: significant bias exists in rudder deflection data). The thrust reversers remained deployed throughout the rollout, but the left engine began spooling down after time 4795 seconds. The airplane came to a stop approximately 40 seconds after touchdown, left of the runway centreline.

Summarizing, the FDR (P/N: 980-4120-DXUN; S/N: 7197) data analysis indicated the following readings as assisted by the state of manufacture, which was the same as the data analysis at the local data analysis facility downloading lap at SAT:

  • Airplane touched down at 139 knots computed airspeed (VREF+6) and at 167 knots ground speed
  • The sink rate at touchdown was approximately 2 feet/second, and the touchdown normal load factor was around 1.1 g. These are not characteristics of a hard landing
  • The airplane had an approximate 2-3 degree left bank angle and a 1 degree right drift angle at touchdown
  • The left main gear collapsed as the airplane completed de-rotation
  • Wheel brakes were applied immediately following touchdown, although it was unclear whether it was manual or autobrake.

The CVR (Pat N: 980-6022-001; S/N: 1732) data recordings revealed that all landing checklist procedures were followed in accordance with the pilot operating procedure handbook manual for the aircraft type.

Wreckage and impact information

The accident occurred during landing on a cleared runway 03R. The on-site observation was that, during landing, the aircraft was subjected to a slight left roll attitude which might have enabled the aircraft to make contact with the runway with the left main landing gear first. It is not clear where the aircraft initially touched down, but at approximately 1 km past the threshold, the left main landing gear tyre marks indicated a form of shuddering manoeuvre beginning slightly and increasing gradually. This was inconsistent with the pilot’s statement that during touchdown the aircraft started vibrating.

The aircraft’s left-hand main landing gear shuddering tyre marks occurred for a distance of approximately 200 m, whereby the runway surface damage was observed at the same place where the No.1 engine began scraping along the runway surface. At this time the left main landing gear had collapsed and was dragged along, causing the left wing to drop. There was evidence of runway surface damage at three intervals of approximately 1.7 m apart, appearing together with the hard tyre contact marks. The damage was consistent with damage caused by the outer wheel tyre assembly as it was dragged along. The damage on both wheel tyres was consistent with damage caused by an object that punched through at the same level with the upper broken torsion link. This may also indicate that both tyres were damaged after the shimmy damper bolt failed and the oscillations were occurring.

There was also evidence of some runway damage which was consistent with the damage caused by the shimmy damper component prior to detaching from the upper torque-link as the landing gear was dragged along. The shimmy damper was found on the left side lying a few metres from the landing gear extension/retraction mechanical actuator, just after the main landing gear doors debris. About several metres away there was an upper torsion link piece of a broken torsion link which connects directly to the shimmy damper. The damage on the shimmy damper is consistent with a component which was subjected to excessive tensile force.

The damage to the trailing edge of the left wing, towards the wing root, was caused by the landing gear as it detached from the main assembly points. The inner flaps were also damaged by the landing gear. The trunnion forward-bearing bolt is designed to fail if the landing gear receives a severe impact. The observations revealed that the fuse lugs on the trunnion link gave a positive reaction characteristic with regard to design failure as it prevented damage to the left wing tanks during the accident sequence.

Comair 6

Photo: South African Civil Aviation Authority Final Report

The wreckage debris was scattered along the runway length during the accident sequence. There was further visible runway surface damage caused by the left landing gear assembly as it moved towards the left side of the runway. The left landing gear was violently detached from the airframe assembly points and came to a complete stop approximately 1.7 km from the threshold during the accident sequence

Comair 7Photo: South African Civil Aviation Authority Final Report

Fire

During the scraping of the No.1 engine (left side) an engine warning initiated. The pilot in command pulled the No.1 engine fire handle, once the aircraft had come to a stop, to cut fuel and hydraulic supply to the engine. On arrival the aerodrome rescue and fire-fighting (ARFF) personnel responding to the accident immediately observed the fire smoke and proceeded to extinguish it.

Tests and research

The failed upper torsion link and the shimmy damper components were shipped to the National Transport Safety Board Laboratory at Washington DC in the United States of America for failure analysis test. Damage assessment inspection was carried out on the components prior to preparing for laboratory tests. (1) The hydraulic tests for both the shimmy damper and its compensator were carried out. (2) The components were later disassembled for inspection. For the full component test report please refer to Annex B in the full final report.

BACKGROUND:

It was reported that on October 26, 2015, during the landing rollout, the left main gear collapsed and departed the aircraft.

SUMMARY:

Examination and testing of the subject shimmy damper and associated parts were performed in the Boeing Equipment Quality Analysis (EQA) lab in Seattle on May 10, 2016. During the testing, the damper failed a step of the hydraulic functional tests. This failure was indicative of a condition that would have impaired damper function and thus may have been a contributing factor to the shimmy event. An attempt was made to isolate the faulty component within the damper. Testing showed that the thermal relief valve within the damper had intermittent internal leakage, which was causing the test failure. In addition to the hydraulic failure, significant wear was found on the upper torsion link bushings. Wear in these areas can also be a contributing factor to shimmy since the wear allows undamped torsional free play of the landing gear.

Based on the information provided regarding the accident site wreckage mapping and the flight data recording (FDR) information, the following discussion was established by the National Transport Safety Board (NTSB):

Shimmy Event Discussion

At the time of writing, there has been no confirmation that the main landing gear collapsed due to a shimmy oscillation. However, the characteristics of the landing are consistent with past landing gear shimmy events. The airplane touched down at a high ground speed and low sink/closure rate. The air/ground discrete transition to GROUND occurred approximately one second after touchdown, indicating that the struts were extended for that period of time. As a result, the torsion links of the shimmy damper remained in an extended, vertical position, where the damper has less mechanical advantage for longer periods of time. Despite the presence of shimmy damper hardware, which is designed to reduce the torsional vibration energy generated during landing, airplanes occasionally experience main landing gear shimmy.

The reference (a) Boeing Aero Magazine article and reference (b) Fleet Team Digest article provide information on the causes of shimmy and how Boeing has addressed the issue. Due to the geometry of the torsion links, the shimmy damper is most effective when the landing gear strut is compressed in the ground mode. Lower touchdown descent rates increase the likelihood of a shimmy damper failure. It is important to note, however, that proper maintenance of the gear components is the best way to prevent shimmy damper failures. The possibility of landing gear shimmy events is greater at high altitude airports. The Aero Magazine article concludes with the following:

Boeing also recommends that pilots strive for a landing with normal sink rates with particular emphasis on ensuring that the auto speedbrakes are armed and deploy promptly at touchdown. An overly soft landing, or a landing in which the speedbrakes do not promptly deploy, allows the landing gears to remain in the air mode longer, which makes them more vulnerable to shimmy. This is especially true when landing at airports located at higher elevations, where the touchdown speed is increased.

Conclusion

A manual approach was performed by the crew that was determined to be unstable, based on the stabilized approach criteria. A combination of a tailwind and high approach speed, while landing at a high altitude airport, resulted in excessive ground speed (167 knots) at touchdown. An extended flare that was the result of an early flare initiation led to touchdown at a low sink rate (1.8 feet/second). The left main gear collapsed approximately 5 seconds after touchdown, and the airplane came to a stop around 35 seconds later. Although the official investigation has not determined the cause of the landing gear collapse, prior service experience on the 737 has shown that touchdown at high ground speeds and low sink rates increases the likelihood of the initiation of main gear shimmy. Prior service history on the 737 has shown that gear collapse is a possible outcome of shimmy.

Note: The full test results are provided as Annex B attachment in the full final report reference.

Operational Guidance

Stabilized Approach Assessment

The Flight Crew Training Manual, with regards to the Flight Safety Foundation’s published criteria for flying a stabilized approach, recommends that a go-around should be initiated if the approach becomes unstabilized under 1000 feet above the ground for instrument meteorological conditions and under 500 feet for visual meteorological conditions.

According to the findings, below 1000 feet radio altitude, the accident airplane did not adhere to three of the recommended stabilized approach criteria. These criteria are summarized below:

  • the airplane is on the correct flight path. The recorded glideslope deviation indicate the airplane was above the intended glide path.
  • the airplane should be at approach speed. For a tailwind approach, the recommended approach speed (VAPP) is VREF+5, which in this case was 138 knots. On average, computed airspeed was 148 knots (VAPP+10) but reached as high as 154 knots (VAPP+16) prior to flare, which exceeded the allowable deviation above approach speed by 6 knots (10 knots is allowed).
  • sink rate is no greater than 1000 fpm. Throughout the approach, there were several sink rate exceedances of 1000 fpm.

Flare Guidance

In this event were also found some failures to adhere to the Flight Crew Training Manual flare guidance recommendations: During final approach, flare was initiated early at a radio altitude of approximately 65 feet, which is higher than the recommended 20 feet. The early flare initiation contributed to the airplane float that led to touchdown at a low sink rate.

2. ANALYSIS

Man

1. The flight crew was licensed, well equipped and qualified for the flight in accordance with existing regulations.

2. The actions and statement of the First Officer, who was flying the aircraft, indicate that his knowledge and understanding of the aircraft system were adequate. No negative operational factor which could have contributed to this accident was noticed during investigation.

Machine

1. The aircraft was certified, equipped and maintained in accordance with existing regulations and approved procedures. The aircraft had a valid Certificate of Airworthiness at the time of the accident, and it was attained in compliance with the existing regulations.

2. During post-investigation, the following were revealed from the Flight Data Recorder analysis and the components failure tests/analysis:

  • According to the recordings of the FDR, the aircraft had an early flare initiated at 65 ft AGL, as compared to the recommended 20ft AGL. This resulted in the aircraft floating and caused a low rate of descent during landing touchdown. The forward touchdown speed was also high, at 167 kt.

This condition was induced with the good intention of achieving a smooth landing touchdown, but it had a negative impact on the landing gear shimmy effectiveness. According to Boeing the low sink rate during landing touchdown increases the likelihood of shimmy damper failure. Due to the geometry of the torsion links, the shimmy damper was less effective during a prolonged touchdown roll with the main gear strut in an extended position. This might have allowed the torsional forces to effect damage to the upper torsion link. The upper torsion link had a remaining lifespan of approximately 26091 landings, of its total expected lifespan of 75000 landings. It is also possible that the torsion link had already lost its maximum strength during the cause of the life it had already spent in operation. At the time of landing, due to the excessive vibration which was not damped at the time, the strut was still extended, the torsion link failed at its weakest design material strength.

  • The shimmy damper also failed a step during tests in which oil was found in the thermal relieve valve. The presence of the oil could have hampered the effectiveness of the shimmy damper. This shows that there had been an internal leak over a long period. This could have been due to the inner seals damage, which was noticed during disassembling of the components following test failure.

During the wheel brakes application, the shimmy damper might have also been less effective, due to the impaired damper failure. The shimmy damper works most during initial touchdown and during brake application.

  • Also, according to the test results, significant wear was found on the upper torsion link’s bushing and the flanges. Although the wear was not far beyond limits it could also play a role due to undamped vibrations continuing to increase shimmy events.

The three above-mentioned findings merged together can play a significant role in inducing the shimmy events that led to this accident. From the wreckage distribution it is evident that the upper torsion link failed first, allowing the shimmy damper attached to the remaining parts that link to the bottom torsion link to drop during wheel oscillation. This played a significant role in a complete landing gear failure. The shimmy damper detached as it sustained damage during the impact sequence, as the main landing gear became detached from the main attachment points. The landing gear detached as per the design fail-safe system, which prevents damage on the wings main spar. Should it be that the main spar damaged and affected the fuel tank, there was a high chance of fire erupting during the accident sequence, due to the running engine and the possible heat generated from impact friction with the runway surface. The results could have been catastrophic.

3. According to the maintenance details prescribed for the aircraft maintenance organisation (AMO) on the shimmy damper, it does not involve overhaul. It is in most cases based on condition; however, the AMO do not have overhauling capabilities. Should it be that during the main landing-gear overhaul, the shimmy damper‘s test and condition remain serviceable, the shimmy damper is reinstalled and it continues in operation. The shimmy damper component has an unlimited life span, unless it is certified unserviceable due to its ineffectiveness during operational tests. Also, in most inspections carried out, AMO personnel only look out for external fluid leaks and wear bushing. The shimmy damper was found with an internal leak during the laboratory tests following the accident.

On the basis of the service history, the investigation concludes that the damage to the shimmy damper seal was sustained during assembly on the last overhaul.

Environment

1. R. Tambo International Airport is at an altitude of 5558 ft above sea level and the pressure altitude of the airport at the time of landing was approximately 5100 ft. The wind was from of a south-southwest direction at approximately 5 kt, increasing to 15 kt prior to touchdown. There was a predetermined tailwind component heading at 34 degrees at 10 kt during touchdown. The effect of the tailwind prolonged the landing roll, but the runway length was sufficient to execute a safe landing in the existing wind conditions.

2. It is every pilot’s desire to execute a safe smooth landing for passenger comfort and aircraft sustainability. These skills are acquired with flying experience. They also are regulated by the environmental conditions at the time of the flight. The technique differs from one operating aerodrome altitude to another, due to pressure altitude and latitude conditions. The aircraft flaring was initiated at an earlier stage at approximately 65 ft AGL as compared to the recommended 20 ft (AGL).

According to the FDR, the pitch angle was correct, but the pilot allowed the airplane to float or attempted to hold it off. When prolonged flare is attempted to achieve a perfectly smooth touchdown, the aircraft is at risk of landing gear torsion link failure, due to ineffectiveness of the shimmy damper as the landing gear remains extended for a long period of time.

 Operation

The flight was conducted in accordance with approved procedure in the company’s Operational Manual. The flight crew carried out a normal radio communication with the relevant ATC at the time of approach and during landing execution.

3. CONCLUSION

Findings

1. The aircraft crew was qualified, licensed and equipped for the operation in accordance with existing regulatory procedures.

2. The flying pilot at the time was medically fit to conduct the flight with sufficient experience on the aircraft type.

3. The aircraft had a valid Certificate of Airworthiness, which was attained in accordance with approved procedure.

4. The aircraft weight and balance were within limits.

5. According to the FDR recordings, the aircraft flare was initiated earlier at 65ft than at 20ft as recommended by aircraft manufacturer, which contributed to the low sink rate.

6. The shimmy damper failed the post-accident lab-test and fluid was found in the thermal relief valve, which could have contributed to the shimmy damper failure.

7. According to the lab results, significant wear was found on the upper torsion link bushing and flange, which could have contributed to undamped vibration continuation.

8. The aircraft had a tailwind component during landing, which could have prolonged the landing distance.

9. The aircraft touchdown was at a high forward speed.

Probable Cause/s

Unstable approach whereby the aircraft was flared too high with high forward speed resulting with a low sink rate in which during touch down the left landing gear experienced excessive vibration and failed due to shimmy events.

4. SAFETY RECOMMENDATIONS

1. The aircraft manufacturer (Boeing) has taken a safety action by publishing The Safety Issued Magazine AERO QTR_03, 13 The Boeing Edge: It is recommended that the Boeing consider the review of Aircraft Operations Manual and / or issue a safety bulletin in light of the findings contained in the Safety Issued Magazine.

2. The safety action taken by the operator:

(a) Pilot’s notice was issued informing pilots of the potential gear shimmy and failure problem during high-speed and soft landings.

(b) Ordered that all operator’s fleet of B737-400 be inspected in order to establish further potential excessive wear and more regular inspections have been scheduled (over-and-above Manufacturer’s requirements) in order to monitor the fleet going forward.

EXCERPTED from South African Civil Aviation Authority Accident and Incident Investigations Division, AIRCRAFT ACCIDENT REPORT CA18/2/3/9494. Released 27th February 2017

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minime2By Laura Duque-Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

Unstable approach and hard landing. Final report

Automation issues, SOPs not consistent with stable approach policy, some training deficiencies and ambiguous standards for flight crew training in relation to automation proficiency, found as contributing factors.

Air Canad Rouge A319

Photo(C) Eddie Heisterkamp Jetphotos.net

Unstable approach and hard landing

Air Canada Rouge LP

Airbus A319, C-FZUG Sangster International Airport Montego Bay, Jamaica 10 May 2014

Aviation Investigation Report A14f0065, released January 2017

1. Factual information

History of the flight

At 1034,  (All times are Eastern Daylight Time -Coordinated Universal Time minus 4 hours) the Air Canada Rouge LP, Airbus A319 (registration C-FZUG, serial number 697), operating as flight AC1804, departed Toronto Lester B. Pearson International Airport (CYYZ), Toronto, Ontario. The flight was the first crew cycle for the 2 pilots. The captain was seated in the left seat and was the pilot flying (PF). The first officer was seated in the right seat and was the pilot monitoring (PM). The aircraft climbed to flight level (FL) 370 for the cruise portion of the flight.

At 1359, before descent and approximately 30 minutes before touchdown, the PF performed an approach briefing for the instrument landing system (ILS) approach to Runway 07 at Sangster International Airport (MKJS), Montego Bay, Jamaica. The approach briefing did not include the aircraft go-around procedure or the specific published missed-approach procedure, contrary to Air Canada Rouge policy.

At 1403, the aircraft began its initial descent from FL 370.

At 1405, the flight crew held a non-operational conversation, lasting nearly 3 minutes, in contravention of Air Canada Rouge policies regarding operational conversation during critical phases of flight, including flight from the top of descent on arrival.

At 1415, approach air traffic control (ATC) at MKJS asked which specific approach the flight crew preferred, offering the area navigation (RNAV) for Runway 07 or the VOR/DME for Runway 07. At this point, the flight crew became aware of a published Notice to Airmen (NOTAM) specifying that the ILS for Runway 07 was not available. The NOTAM had been included in the company flight release documents before departure but had not been noticed by the flight crew. The crew decided to perform the VOR/DME Runway 07 approach.

At 1417 (12 minutes before landing), the PF re-briefed the PM for the VOR/DME approach to Runway 07. As with the initial approach briefing for the ILS approach to Runway 07, the PF did not brief the aircraft go-around and published missed-approach procedures for the VOR/DME approach to Runway 07. The PF advised that a managed approach would be conducted (In a managed approach, “the aircraft is guided along the FMS [flight management system] lateral and vertical Flight Plan and speed profile. These modes and targets are armed or engaged by pressing the FCU [flight control unit] knobs.” Air Canada Rouge, Aircraft Operating Manual A319 (AOM), Volume 1 (10 May 2013), Standard Operating Procedures, section 1.04.00, p. 4).

During the re-briefing, the PF indicated that the final approach fix (FAF) crossing altitude was 2000 feet above sea level (asl), with a flight path angle (FPA) of 3.2 degrees.

At 1421:20, the flight crew held a non-operational conversation that ended at 1422:04 (approximately 8 minutes before touchdown), while the aircraft was descending through 10 000 feet.

At 1423:56 (6 minutes before landing), ATC queried whether the flight crew was able to proceed directly to LENAR9 at that time. The flight crew advised ATC that they were able to do so, and the aircraft was then cleared to LENAR. At this point, the aircraft was being flown using the autopilot and autothrust systems. (LENAR is the name of the initial fix for the very high frequency (VHF) omnidirectional range with associated distance measuring equipment (VOR/DME) Runway 07 approach, located 10.8 nautical miles from the threshold of Runway 07).

AC1

At 1424:46, before turning onto the final approach track, the PF selected a target speed of 190 knots on the flight control unit (FCU); the autothrust decreased the thrust and, as a result, the aircraft began to decelerate from 250 knots. The aircraft was level at 3000 feet.

At 1425:03, the PF requested flaps 1, which is the first configuration change in the approach sequence.

From 1425:28 to 1426:02, the PM was engaged in dialogue with ATC. During this time, the aircraft turned onto its final approach track.

At 1425:44, the final approach track was intercepted from the left (north), at a distance of approximately 9.6 nautical miles (nm) from the threshold (inside of LENAR). The aircraft was at an altitude of 3000 feet, with flaps 1 selected. According to Air Canada Rouge standard operating procedures (SOP), at this point (4 nm before the FAF), the aircraft should be configured with flaps 2. The autopilot was engaged and the autothrust was on. The airspeed was approximately 200 knots, and the aircraft was slightly above the 2.95-degree precision approach path indicator (PAPI), but below the 3.2° FPA. The aircraft began its final approach descent. Shortly afterwards, the flight mode annunciator (FMA) lateral and vertical modes changed to NAV and FINAL DES  respectively, indicating that the aircraft was being managed by the flight management and guidance system (FMGS). The selected airspeed was still 190 knots. In these modes, the aircraft will fly the required lateral and vertical flight path, while the autothrust will vary the thrust to maintain the selected speed.

At 1426:00, 9.2 nm from the runway, the airspeed slowed to 195 knots. The PF selected a target speed of 180 knots to slow the aircraft down, and the autothrust system reduced the engine thrust to idle. The aircraft was at an altitude of 2950 feet.

At about 1426:08 (8.7 nm from the runway), the PF requested landing gear down to expedite the descent. This request was outside of the normal aircraft configuration sequence in Air Canada Rouge SOPs. The normal sequence is to select flaps 2 before extending the landing gear. However, the SOPs permit flight crew to lower the landing gear at any time during the approach, to aid in the descent.

At 1426:25, the airspeed was 188 knots. Using the FCU, the flight crew changed the selected target speed from 180 knots to 190 knots, then to 200 knots. Because of this selection, the autothrust momentarily increased the engine thrust, resulting in an increase in airspeed. The descent rate also increased, reaching 2000 feet per minute (fpm).

At 1426:28, the landing gear was down and locked. The aircraft was 7.7 nm from the runway and 1.7 nm from the FAF, with flaps 1 selected. At this point, according to Air Canada Rouge SOPs, the aircraft should have already been configured with flaps 3 selected.

At 1426:37, the aircraft was 1.6 nm from the FAF. The flight crew changed the target speed from their previous selection of 200 knots to a managed target speed11 of 134 knots, equivalent to the final approach speed (VAPP).12 At this point, the aircraft’s airspeed was 198 knots, and its altitude was decreasing through 2440 feet. As a result of the change in target speed, the aircraft began to decelerate.

At 1427:02, the aircraft crossed the FAF at the appropriate height (2000 feet) with an airspeed of 188 knots (VAPP plus 54 knots). At that time, the landing gear was down, with flaps 1 selected. According to Air Canada Rouge SOPs for a non-precision managed approach, at this point, the aircraft should have been stable at VAPP, with landing gear down and flaps 3 selected.

During the FAF crossing, using the vertical speed/flight path angle (VS/FPA) knob on the FCU, the PF selected 3.2° FPA, which is the appropriate FPA from the FAF. The FMA lateral and vertical modes changed to track mode (TRK) and to FPA, respectively. The flight crew did not perform the FAF-passage verbal calls required by the SOPs or their respective actions, which include setting the appropriate missed-approach altitude in the FCU.

At 1427:13, the PF disengaged the autopilot as the aircraft descended through 1780 feet, at a distance of approximately 5.2 nm from the threshold; airspeed was 186 knots. The remainder of the approach was flown manually by the PF, with the autopilot off.

At 1427:16, while the aircraft was descending through 1690 feet, 5 nm from the runway, with an airspeed of 187 knots, the PF requested flaps 3. The PM momentarily selected flaps 3, from flaps 1. The airspeed was 2 knots faster than the maximum flap selection speed for flaps 3, and the PM quickly retracted the flap lever to flaps 2. Contrary to Air Canada Rouge SOPs, the PM did not verbalize that the speed was correct for the selected flap setting, nor did he communicate the changes in flap position to the PF. During these flap selections, there was a radio call from ATC, clearing the aircraft to land.

Although data from the cockpit voice recorder (CVR) indicated that the PF had requested flaps 3, the investigation determined that the PF believed that he had requested flaps 2.

At 1427:22, the flight crew pulled the altitude selector (ALT/SEL) on the FCU. However, the FCU-selected altitude was set at 2000 feet. As a result, since the aircraft was below that altitude, the vertical mode changed from FPA to open climb (OP CLB) mode, and the autothrust changed to climb thrust (THR CLB) mode. The autopilot was off, so the aircraft did not climb, as requested by the automation. However, the autothrust increased the engine thrust from 34% to 87%, which resulted in an increase in airspeed.

At 1427:25, approximately 4.5 nm from the runway, with an airspeed of 185 knots and at an altitude of 1530 feet, the aircraft levelled off momentarily. Shortly afterwards, the aircraft began to deviate above the 3.2° FPA (Appendix A in the full report).

At 1427:26, the PM moved the flap selector lever from flaps 2 to flaps 3 a second time, again without communicating the selection or acknowledging that the speed was correct for the flap setting. Owing to the thrust increase described above, the airspeed increased to greater than the 185 knots maximum speed for flaps 3 selection, reaching 193 knots.

Within 3 seconds of the flaps 3 selection, the flaps extended to the flaps 3 position and the flight data recorder (FDR) recorded a master warning. A continuously repetitive chime, consistent with the flap overspeed warning, sounded for about 3.5 seconds. (

The Air Canada Rouge Aircraft Operating Manual A319 indicates that the maximum airspeed is 200 knots at flaps position 2, and 185 knots at flaps position 3. )

At 1427:29, the flight crew changed the FPA on the FCU from 0° to 3.2°. As a result, the FMA lateral and vertical modes returned to TRK and FPA, respectively; the autothrust changed from THR CLB to SPEED mode.

At 1427:32, the PM again momentarily retracted the flaps to the flaps 2 position. The PF disengaged the autothrust (by pressing the instinctive disconnect pushbutton and moving thrust levers to idle). The PM communicated to the PF that the flaps were at position 2.

At 1427:38, the PM moved the flap lever to the flaps 3 position for the final time, where it remained for the landing. The PM advised the PF of this flap selection. The aircraft was descending through 1420 feet, with an airspeed of 182 knots, thrust levers at idle, and autothrust off. The vertical rate of descent was 300 fpm.

At 1427:42, the PF stated that the aircraft was too high and that he was correcting, then stated that the autothrust was off. The PM did not hear the statement that the autothrust was off. The aircraft continued on the approach, and the rate of descent increased to 1400 fpm. During this time, the aircraft descended and began to converge on the 3.2° FPA followed by the FPA for the 2.95° PAPI. The aircraft was established on the PAPI at approximately 1428:24 (1.9 nm from the runway).

At 1427:52, the PM initiated the callouts associated with the landing flap selection portion of the final approach and landing check. The PM called out “autothrust,” which is the first callout item. The PF did not immediately respond, but shortly afterwards he initiated a dialogue regarding the FAF and the missed-approach altitude, interrupting the checklist. The PF requested that the PM dial in the missed-approach track and altitude. The pre-landing check was not completed. The autothrust remained off, and thrust levers remained at idle.

During the exchange between the PF and PM, the aircraft continued from 3.8 nm to 1.9 nm from the runway, descended from 1430 feet to 670 feet, and decelerated from 177 knots to 160 knots. The aircraft also descended through the Air Canada Rouge 500-foot arrival gate (100 feet above minimum descent altitude) used for the stabilized approach criteria, at which time the stabilized approach check must be completed, according to the Air Canada Rouge SOPs. The check was not done at this time.

At 1428:34, when the aircraft was 1.5 nm from the threshold, at 500 feet, with an airspeed of 155 knots, the flight crew acknowledged that the aircraft was back on profile.

At 1428:44, the flight warning computer (FWC) issued an aural alert of “four hundred.”

At 1428:48, the PF made the 500-foot stable approach call, which included “a hundred above, stable, minimums, runway in sight.” The aircraft was approximately 1 nm from the runway, at 370 feet, with an airspeed of 146 knots (VAPP plus 12 knots). The engines were at idle thrust, with autothrust off. At that time, the aircraft did not meet the Air Canada Rouge stabilized approach criteria, as the airspeed was high, the thrust setting was at idle, and the landing checklist was incomplete. The stabilized approach criteria will be explained in greater detail later in this report.

At 1429:05, the flight crew confirmed with each other that they were cleared to land. The aircraft was approximately 0.5 nm from the threshold; the airspeed was decreasing through 134 knots (VAPP). The aircraft was descending through approximately 200 feet above ground level (agl) with a pitch of 5.6° nose-up, and engine thrust was at idle; the rate of descent was 570 fpm. At 1429:13, the FWC emitted an aural warning of “one hundred.”

At 1429:15, approximately 0.2 nm from the threshold, the PF applied nose-up side-stick input, consistent with the landing flare, as the aircraft descended through 80 feet agl. The airspeed was 123 knots (11 knots below VAPP), the rate of descent was approximately 650 fpm, and the calculated true angle of attack (AOA) was approximately 9.9°. The normal technique is to reach a 30-foot flare height at VAPP in a stabilized condition and to begin a progressive flare while simultaneously closing the thrust levers, in order to be at idle before touchdown. (Air Canada Rouge, Aircraft Operating Manual A319 (10 May 2013), Standard Operating Procedures, Normal Landing, 1.04.13, p. 1.)

At 1429:17, the FWC issued the aural alert “fifty.”

At 1429:18, at 40 feet agl, the airspeed was decreasing through approximately 115 knots (19 knots below VAPP). The pitch angle had stabilized at 9.8° nose-up, the rate of descent was approximately 860 fpm, and the calculated true AOA was approximately 13.8°. At this point, the aircraft was in a low-energy state. The FWC issued an alert of “thirty,” and the thrust levers were momentarily advanced to maximum take-off thrust (take-off/go-around [TOGA]) power. The engine thrust responded but increased by only 4% before the aircraft touched down.

During the flare, with full nose-up side-stick input, the nose-up pitch command increased, the calculated true AOA reached a maximum of approximately 15.3°, and the elevator position oscillated between 1° and 5° nose-up. This sequence is consistent with alpha protection, a mode of the aircraft’s high-AOA protection system that enables the PF to pull the side-stick full aft and achieve the best possible lift, minimizing the risk of aerodynamic stall or control loss.( Air Canada A319 Flight Crew Training Manual (29 July 2011), Normal Operations, Operational Philosophy, Flight Controls, p. 10.) The pitch attitude subsequently began to decrease from the maximum 9.8° nose-up value before touchdown.

At 1429:21, the aircraft touched down hard, with a vertical load factor of 3.12g. The airspeed was 108 knots, and the pitch angle was 7.7° nose-up. At main gear touchdown, the calculated distance past the displaced threshold was approximately 125 feet.

Immediately following the touchdown, the ground spoiler was extended and the autobrake was activated normally, and the flight crew applied reverse thrust. The aircraft taxied off the runway without further incident.

The flight crew reported the hard landing, after which an initial inspection of the aircraft was performed. After a review of the FDR data, Air Canada Rouge maintenance personnel inspected the aircraft.

Injuries to persons

AC tabla 1

Damage to aircraft

The aircraft did not sustain structural damage or damage that adversely affected its flight characteristics. However, it was determined that the left and right main landing gear had been subjected to a high load exceedance. As a result, a flight permit was obtained from Airbus and Transport Canada (TC) to fly the aircraft to Miami, Florida, with the landing gear down. Both left and right shock absorbers were replaced as a precaution, as recommended by Airbus.

Personnel information/ Flight crew

The flight crew was certified and qualified within existing regulations. The occurrence flight was the first time the crew had flown together.

The PF had approximately 10 000 hours of total flight time, including 4200 hours on the aircraft type, 500 of which were as pilot-in-command. In October 2013, the PF was hired by Air Canada Rouge as a captain on the Airbus A319. Previously, he had been employed by Air Canada mainline since March 2006. He had received initial training as a first officer on the A319/A320 in 2008 and had completed upgrade training to become a captain in December 2013.

The PM had approximately 12 000 hours of total flight time, including 475 hours on the Airbus A319/A320, all of which were as second-in-command. His employment with Air

Canada Rouge began in October 2013. Previously, he had been employed by Air Canada mainline since March 2013. The PM’s biannual recurrent training had been conducted in October 2013.

Organizational and management information

1. General

Air Canada Rouge is a wholly owned subsidiary of Air Canada. It became a Canadian Aviation Regulations (CARs) Subpart 705 operator in June 2013 and had its first revenue flight in July of that year. The airline is fully integrated into the Air Canada mainline and Air Canada Express networks. According to the TC Canadian Civil Aircraft Register, the company operates 20 Airbus A319 and 14 Boeing 767 aircraft.

2. Flight crew training

Air Canada uses the advanced qualification program training system that is common among larger airlines. This training system does not involve traditional pilot proficiency checks following training but instead, includes validation sessions to assess the trainee. However, Air Canada Rouge uses the traditional method, in which a pilot proficiency check follows the requisite training.

Although the validation of trainees is accomplished differently at Air Canada Rouge than at Air Canada, the training is similar. The session summaries for each training event are identical at both airlines. The autothrust simulator training is the same for both Air Canada and Air Canada Rouge flight crews.

At the time of the occurrence, simulator training in autothrust-off approaches was part of the training syllabus at both airlines for flight crew members receiving initial type training and recurrent training. As Air Canada Rouge has a 36-month recurrent training cycle, the items in the initial training syllabus are covered again at some point in the 36-month period.

The PF had completed the first of the 6 recurrent training modules in the 36-month matrix, and the PM was not yet required to complete the first module. Both training schedules were in accordance with company policy and current regulations.

When the PF was upgraded to captain, he received the upgrade training that is provided to flight crew who are currently qualified on the aircraft type as first officer and are upgrading to captain. There is no training in autothrust-off approaches in the upgrade course, and none is required by regulation. The PF had completed training in non-autothrust approaches during his initial A319/A320 training in 2008.

Crew resource management (CRM), including threat and error management, forms part of the initial flight-crew training syllabus at Air Canada Rouge, and a refresher course is given during recurrent training.

At the time of the occurrence, Air Canada Rouge did not provide flight crews with simulator training to recognize unstable approaches, nor was such training required by regulation.

3. Air Canada Rouge stable approach policy

At the time of the occurrence, the Air Canada Rouge stable approach policy differed, in part, from that recommended by the Flight Safety Foundation (FSF) (section 1.18.2).

Air Canada rouge Stable Approach Policy is built around an Arrival Gate concept whereby a flight shall not continue the approach unless the required criteria for each Arrival Gate are met. There are two Arrival Gates for every approach; the first is the FAF (or FAF equivalent), the second Arrival Gate is at 500 feet AGL (or 100′ above minimums, whichever is higher). A Go-around is mandatory if the criteria for each Arrival Gate is not met [sic]. (Air Canada Rouge, Flight Operations Manual (17 February 2014), 8.11.6 Stabilized Approach Criteria).

The Air Canada Rouge criteria for a stabilized approach at the FAF arrival gate did not include several of the FSF-recommended criteria, including airspeed and sink rate, configuration, power settings, briefings or checklist completion. Aircraft were required to meet the recommended criteria only at the 500-foot gate, regardless of weather conditions.

4. Air Canada Rouge stabilized approach criteria

According to the Air Canada Rouge stabilized approach criteria, the aircraft was stable at the FAF arrival gate. However, the airspeed was 54 knots faster than VAPP, and the aircraft was not configured with the proper flaps settings as per the Air Canada Rouge SOPs. The aircraft was not stable at the 500-foot arrival gate (actually 710 feet as per the SOPs) because of its excessive airspeed, vertical speed deviations, incomplete landing checklist, and unstabilized thrust.

Air Canad Rouge A319 (2)

Photo (C) Galen Burrows Jetphotos.net

2 Analysis

Introduction

The flight crew was certified and qualified in accordance with existing regulations, and nothing was found to indicate that there was any aircraft failure or system malfunction that contributed to the occurrence before or during the flight. The analysis will focus on explaining how the series of operational and non-operational events encountered by the crew drew their attention away from monitoring and from executing a stable, non-precision approach, and resulted in their lack of awareness of the aircraft’s low-energy state just before touchdown. The analysis will also explain the defences that were in place but that were ineffective in preventing an unstable approach from being continued to a landing.

Flight planning and briefing

Before departure, the flight crew did not notice the Notice to Airmen (NOTAM) explaining that the instrument landing system (ILS) for Runway 07 was not available. As a result, they initially performed an approach briefing for the inoperative ILS approach. Following a call from air traffic control (ATC) enquiring about their selected approach, a second approach briefing for the very high-frequency omnidirectional range with associated distance measuring equipment (VOR/DME) Runway 07 approach was conducted. Neither briefing included the aircraft go-around procedure or the specific published missed-approach procedure, which form part of the first approach briefing of the day according to company procedures. In this occurrence, the flight crew was not under any time pressure. It is possible that, given the visual meteorological conditions, a go-around was deemed unlikely, and this may have reduced the perceived importance of the required briefings.

Briefings such as those for approach and for a missed approach are designed to establish a common action plan, to set priorities, and to cue altitudes and other critical information to memory. If flight crews do not conduct thorough briefings, including missed-approach briefings, they may not have a common action plan or set priorities, resulting in reduced crew coordination, which might compromise the safety of flight operations.

Managing non-operational and operational activities during approach

As the flight proceeded toward the final approach track, the flight crew engaged in non-operational conversation. As a countermeasure against crew distraction, non-operational conversation during critical phases of flight is prohibited by company policy. During this time, the crew also received a call from ATC and reprogrammed the flight management and guidance system (FMGS) for a direct flight to the LENAR waypoint.

The Air Canada Rouge standard operating procedures (SOPs) guide flight crews to configure the aircraft at flaps 2 at least 4 nautical miles (nm) prior to reaching the final approach fix (FAF); however, in this occurrence, the aircraft remained configured at flaps 1 until after the aircraft had passed the FAF. Managing the series of operational and non-operational events before the final approach track (i.e., communicating with ATC, reprogramming the FMGS, and carrying out a conversation) may have drawn the flight crew’s attention away from appropriately managing airspeed and configuring the aircraft. Also, the aircraft turned onto the final approach track after the LENAR waypoint, which reduced the amount of time the flight crew had to configure the aircraft and manage airspeed.

If flight crews are distracted by other operational and non-operational activities and do not follow SOPs, critical tasks associated with flying the aircraft may be delayed or missed.

Unstable approach – occurrence flight

1. Managing the aircraft systems with and without automation

When the aircraft was established on the final approach track, it was at the approximate altitude required for the desired 3.2° approach path. However, because the aircraft was still decelerating, its airspeed was greater than the target airspeed that had been selected. At that point, the aircraft vertical and lateral modes were managed, meaning that the autopilot or flight director systems were directed by the FMGS. When this is the case, the aircraft should follow the vertical and lateral approach path generated by the FMGS, and the autothrust (if in managed mode) should adjust the engine thrust as required.

In this occurrence, however, the autothrust was in a non-managed mode, and the selected speed was 180 knots. As a result, the aircraft was attempting to maintain 180 knots. At this point, the aircraft should have been decelerating to meet the FAF final approach speed (VAPP) of 134 knots. If the autothrust had been in a managed mode, the aircraft would have decelerated automatically.

The aircraft did not immediately start to descend, likely because it was moving too fast to descend on the given approach profile from its current location. Subsequently, the crew lowered the landing gear to slow down the aircraft and expedite the descent.

The flight crew then selected a higher target speed on the flight control unit (FCU), increasing it from 180 knots to 190 knots, and finally to 200 knots, likely in an attempt to increase the vertical descent rate. The descent rate increased, reaching 2000 feet per minute (fpm). However, the aircraft also accelerated, reaching 198 knots, when it should have been decelerating. The flight crew’s selection of a higher target speed before the FAF resulted in an increased-thrust and high-airspeed condition. This condition contributed to the crew’s confusion and misunderstanding of what the aircraft was doing and resulted in their mismanagement of the configuration sequence.

Shortly afterwards (12 seconds later), as a result of flight crew input, the target speed switched from a selected airspeed to a managed airspeed of 134 knots (VAPP). As a result, the autothrust reduced the engine thrust, and the airspeed began to decrease.

After deviating above the approach profile, the aircraft crossed the FAF at the appropriate altitude; however, its airspeed (188 knots) was 54 knots faster than VAPP, with flaps 1 still selected. Company SOPs state that the aircraft should cross the FAF stabilized at VAPP, with flaps 3 selected.

At this point, the pilot flying (PF) selected a flight path angle (FPA) of 3.2° on the FCU, which is the appropriate FPA from the FAF to the runway. The vertical flight mode changed to FPA. These modes were appropriate for the aircraft’s position on the approach and were within company and aircraft operating procedures. The autopilot and autothrust were on.

As the aircraft passed the FAF arrival gate, it met all of the stabilized approach criteria in the company policy. The aircraft had regained the approach profile, and its vertical speed was acceptable. The aircraft was tracking appropriately laterally. However, its airspeed was much higher than that specified by the SOPs, and its flaps were set to 1 instead of 3. Therefore, although the stabilized approach criteria were met, the airspeed and flap setting were contrary to the SOPs. If an air operator’s SOPs are not consistent with its stable approach policy, there is a risk that flight crews will continue an approach while deviating from the SOPs, resulting in an unstable approach.

According to company SOPs, the landing gear is normally selected down after flaps 2 is selected and before flaps 3 is selected. However, the SOPs permit flight crew to lower the landing gear at any time owing to operational requirements. During the occurrence approach, the landing gear selection was made outside of the normal procedural sequence, before the flaps 2 selection, to increase the deceleration and descent rate in response to the first high-airspeed condition.

The PF requested flaps 3 from the pilot monitoring (PM), bypassing flaps 2. The PF had intended to request flaps 2, but his error was not detected by the PM. The PM moved the flap selector from flaps 1 to flaps 3, although the speed was higher than the maximum allowable for that flap setting. It could not be determined why there was no corresponding call from the PM to ensure that the speed was correct, nor why there was no communication between the flight crew members clarifying the flap settings. During this time, there was also a call from ATC. The PM made 2 further attempts to select flaps 3. On the third attempt, the flaps reached the flaps 3-position.

Shortly afterwards, the flight crew pulled the altitude selector (ALT/SEL) knob on the FCU; as a result, the flight modes switched to open climb (OP CLB) and climb thrust (THR CLB). Consequently, there was a sudden and substantial increase in thrust from near idle to 87%. The PF had disengaged the autopilot, so the aircraft did not climb, as commanded by the automation. However, given that the autothrust was still engaged, the airspeed increased a second time, and a flap overspeed alarm sounded.

The increased speed and climb commanded by the automation when the flight crew pulled the ALT/SEL knob were not required during this phase of the approach. Furthermore, when the knob was pulled, the preselected altitude was above the current altitude, which did not correspond to any descent strategy. This further destabilized the aircraft. There are several other knobs and pushbuttons on the FCU and on the adjacent panels in the area of the glare shield. The pulling of the ALT/SEL knob was likely the result of an inadvertent FCU selection; that is, the flight crew had meant to select a different input.

The inadvertent FCU selection resulted in a second high-airspeed and increased-thrust condition. The aircraft deviated above the approach profile between the FAF and the 500-foot arrival gate, and a flaps-3 overspeed alarm sounded. In response, the PF disengaged the autothrust, which he called out to the PM.

2. Unstable approach

The PM initiated the flap-selection check after the PF had disengaged the autothrust and the PM had configured the aircraft with flaps 3. At the “Autothrust” item of the checklist, the check was interrupted by a discussion about the missed-approach altitude and was subsequently not completed. These 2 operational events occurred as the aircraft descended past the 500-foot arrival gate (100 feet above minimums), and a call of “Stable” was not made. The timing of the operational discussion as the aircraft descended past the 500-foot arrival gate may have diverted the attention of the PM from his duties, causing an essential task (a “Stable” call) to be missed. As a result, the flight crew missed an opportunity to recognize an unstable approach.

When the aircraft was on final approach, at 400 feet, the flight warning computer (FWC) annunciated “four hundred.” Following the FWC annunciation, the PF made the stable call of “hundred above, stable, minimums.” However, the PF made the “Stable” call when the aircraft was not stabilized, as its airspeed was high, the landing checks were incomplete, and the thrust was at idle. As a result, the flight crew continued an unstable approach. The aircraft had returned to the approach vertical profile, which was likely what the PF recognized as stable.

3. Energy management

As previously explained in the report, an aircraft’s energy condition is a function of its airspeed (and airspeed trend), altitude, drag, and thrust. In this occurrence, just before the first high-airspeed condition, the flight crew extended the landing gear, thereby increasing drag. However, the airspeed did not decrease; rather, it increased, because the crew selected a higher airspeed on the FCU. The flight crew eventually returned the autothrust to a managed mode; as a result, the target airspeed decreased to VAPP, and the aircraft began to decelerate.

The second high-airspeed condition occurred when the PF called for flaps 3 after the aircraft had crossed the FAF. A series of inputs to the FCU by the flight crew then caused the aircraft to increase thrust because of its mode of operation, which resulted in the flight crew misunderstanding what the aircraft was doing. To reduce airspeed and regain control, the PF disengaged all of the automation, including the autothrust.

Management of the aircraft’s energy condition diverted the flight crew’s attention from monitoring and controlling airspeed during the descent. As a result, the aircraft passed the FAF arrival gate at a high airspeed and with a flaps configuration that was not in accordance with the SOPs.

It is normal practice and standard procedure for flight crews to use autothrust for landing and to maintain thrust above idle to maintain the approach profile and facilitate a missed approach. However, the flight crew’s management of the second high-airspeed condition and the interruption of the landing flap check resulted in an autothrust OFF and thrust IDLE condition of which the flight crew was unaware.

The flight crew did not recognize that the airspeed was decaying as the aircraft approached the runway, nor that the autothrust was off. While on short final approach, the airspeed decayed well below VAPP, placing the aircraft in an undesired aircraft state at a very low altitude. The PF applied full nose-up side-stick input, and the angle of attack (AOA) reached maximum levels. As a result, during the flare, the aircraft’s AOA protection system engaged, reducing the pitch angle. The protection system functioned as designed, and as a result no significant nose-up elevator movement occurred, although full nose-up side-stick input had been applied before touchdown.

The crew were unaware of the low-energy state just before touchdown, as they believed that the autothrust was on. At 50 feet before touchdown, the flight crew suddenly realized that airspeed had been decaying and applied full manual thrust (i.e., maximum take-off thrust); however, in the time remaining before touchdown, the thrust increased by only 4%. When the flight crew recognized the undesired aircraft state, the late addition of engine power was insufficient to arrest the descent rate, resulting in a hard landing.

4. Monitoring approach stability

This occurrence involved factors that have been shown to increase the likelihood that an unstable approach is continued to a landing. For example, there were no environmental issues, such as wind shear, runway contamination, or instrument meteorological conditions, that would increase the perceived risk of the situation. As a result, the pilots likely anticipated a routine approach and landing. This may have contributed to the crew’s acceptance of deviations from the stabilized approach criteria. Until it reached the 500-foot stabilized approach gate, the aircraft was slightly high and fast but regained the profile twice as the flight crew worked to manage the conditions of high airspeed and increased thrust. The actions taken by the crew to reduce the airspeed indicated that they were aware of the high and fast energy state of the aircraft. Past the 500-foot arrival gate, with the autothrust disengaged and the thrust at idle, the aircraft’s airspeed continued to decay, resulting in an on-profile and low-energy state by 100 feet above ground level.

A number of situational factors likely contributed to the flight crew not recognizing that the aircraft had shifted from a high-energy state to a low-energy state:

  • The flight crew had spent most of the approach working to reduce airspeed while descending and had finally reduced airspeed sufficiently just past the 500-foot arrival gate. They did not anticipate a low-airspeed condition.
  • The flight crew was behind schedule in changing flap configurations and in approach-and-landing checks until just past the 500-foot arrival gate. They believed the aircraft to be stabilized at that point.
  • Procedures, parameter-deviation calls, and checks were interrupted, delayed, or missed, reducing the flight crew’s awareness of actual flight parameters and aircraft system states.
  • Monitoring of the overall approach was not maintained as the flight crew focused on resolving the condition of high airspeed and increased thrust.

Air Canada Rouge SOPs require the PM to call out excessive deviations from normal sink rate or from the approach profile in both visual flight rules and instrument flight rules meteorological conditions. In this occurrence, it could not be determined why the PM did not recognize the flight parameters that indicated that the approach was unstable. It is possible that the transition from the PF flying the aircraft with the automation on to flying the aircraft manually, combined with the thrust increases, contributed to a high workload, and that these deviations were therefore not noted by the PM. In addition, because the flight crew regained the approach profile following each airspeed deviation, there were recent cues that the aircraft, which was perceived as stable, was on profile. As a result, the degree of instability, including the shift from a high-airspeed condition to a low-airspeed condition, was not identified, and a go-around was not initiated.

Air Canada Rouge had stabilized approach criteria and policy, a no-fault go-around policy, and a safety management system hazard- and occurrence-reporting policy. Despite these factors, which encourage flight crews to conduct a go-around when an aircraft is not stabilized for approach, the unstable approach was continued. The flight crew did not adhere to the SOPs, which required the monitoring of all available parameters during approach and landing. With both flight crew members focused on the airspeed conditions and aircraft configuration delays, the instability of the approach was not identified and a go-around was not conducted.

Current defences against continuing unstable approaches have proven less than adequate. Unless further action is taken to reduce the incidence of unstable approaches that continue to a landing, the risk of controlled flight into terrain (CFIT) and of approach-and-landing accidents will likely persist.

5. Automation

At Air Canada Rouge, it is normal procedure to fly approaches in managed mode. The flight crew’s handling of the 2 high-airspeed conditions (i.e., thrust increase before the FAF and the climb thrust increase after the FAF) while attempting to maintain the approach profile demonstrated that the crew misunderstood what the aircraft was doing in its given modes of automation. After a few attempts to reduce airspeed by directing the automated systems, and following the unexpected thrust increase, the PF disengaged all of the automation, including the autothrust, in order to control the aircraft manually. This disengagement is a recommended course of action in such a situation, and the appropriate calls were made.73

Further, the PF’s switching to manual control resulted in the aircraft slowing down and regaining the approach profile near the 500-foot arrival gate. However, the PF did not remember that the autothrust was disengaged and that thrust was at idle as the aircraft continued to landing.

6. Crew resource management and standard operating procedures

As part of the normal discharge of their operational duties, flight crews employ countermeasures to prevent threats, errors, and undesired aircraft states from reducing safety margins during flight operations. Examples of such countermeasures include checklists, checks, briefings, calls, and SOPs, as well as crew resource management (CRM) skills (i.e., decision making, automation management, communication, and maintenance of situational awareness and attention). In this occurrence, throughout the approach to landing, critical elements of communication between the flight crew, including checks, calls, and cross-checks of excessive flight parameter deviations and flight mode annunciator (FMA) mode changes, were delayed or missed altogether.

Humans are inclined to focus attention on responding to problems or abnormal situations, even when the issues involved are benign in nature. CRM skills and SOPs, and regular training in them are designed as a countermeasure against flight crews focussing on threats and errors rather than on flying the aircraft or managing an undesired aircraft state. If flight crews do not adhere to standard procedures and best practices that facilitate the monitoring of stabilized approach criteria and excessive parameter deviations, there is a risk that threats, errors, and undesired aircraft states will be mismanaged.

7. Flight crew training

Air Canada Rouge has a stabilized approach criteria and policy. However, at the time of the occurrence, Air Canada Rouge did not provide flight crews with simulator training in recognizing an unstable approach leading to a missed approach. As a result, the occurrence flight crew did not recognize the multiple deviations in airspeed and thrust or the deficiencies in coordination and communication, and they continued the approach well beyond the stabilization gates. Training scenarios that involve go-arounds following an unstable approach may increase the likelihood that pilots will carry them out during active flight operations.

At the time of the occurrence, Air Canada Rouge did not include autothrust-off approach scenarios in each recurrent simulator training module, nor are they required to do so by regulation. The flight crews routinely fly with the automation on. As a result, the occurrence flight crew was not fully proficient in autothrust-off approaches, including management of the automation.

According to the Commercial Air Service Standards (CASS), air operators are required to provide flight crew members with training in all types of instrument approaches, using all levels of automation. At the time of the occurrence, Air Canada Rouge was providing training for autothrust-off approaches during initial training, but not during recurrent training. However, there is no specification in the CASS regarding the frequency of such training or how it is to be conducted, only that all items for the initial training syllabus must be covered over a defined period of time (through a cycle).

If standards for flight crew training in relation to automation proficiency (CASS 725.124) are not explicit with regard to frequency, there is a risk that air operators will exclude critical elements from recurrent training modules and that flight crews might not be proficient in all levels of automation.

3. Findings

Findings as to causes and contributing factors

  1. The flight crew’s selection of a higher target speed before the final approach fix resulted in an increased-thrust and high-airspeed condition. This condition contributed to the crew’s confusion and misunderstanding of what the aircraft was doing and resulted in their mismanagement of the configuration sequence.
  2. The inadvertent flight control unit selection resulted in a second high-airspeed and increased-thrust condition. The aircraft deviated above the approach profile between the final approach fix and the 500-foot arrival gate, and a flaps-3 overspeed alarm sounded. In response, the pilot flying disengaged the autothrust.
  3. The timing of the operational discussion as the aircraft descended past the 500-foot arrival gate may have diverted the attention of the pilot monitoring from his duties, causing an essential task (a “Stable” call) to be missed. As a result, the flight crew missed an opportunity to recognize an unstable approach.
  4. The pilot flying made the “Stable” call when the aircraft was not stabilized, as its airspeed was high, the landing checks were incomplete, and the thrust was at idle. As a result, the flight crew continued an unstable approach.
  5. Management of the aircraft’s energy condition diverted the flight crew’s attention from monitoring and controlling airspeed during the descent. As a result, the aircraft passed the final approach fix arrival gate at a high airspeed and with a flaps configuration that was not in accordance with the standard operating procedures.
  6. While on short final approach, the airspeed decayed well below final approach speed (VAPP), placing the aircraft in an undesired aircraft state at a very low altitude.
  7. When the flight crew recognized the undesired aircraft state, the late addition of engine power was insufficient to arrest the descent rate, resulting in a hard landing.
  8. The flight crew did not adhere to the standard operating procedures, which required the monitoring of all available parameters during approach and landing. With both flight crew members focused on the airspeed conditions and aircraft configuration delays, the instability of the approach was not identified and a go-around was not conducted.
  9. Air Canada Rouge did not provide flight crews with simulator training in recognizing an unstable approach leading to a missed approach. As a result, the occurrence flight crew did not recognize the multiple deviations in airspeed and thrust or the deficiencies in coordination and communication, and they continued the approach well beyond the stabilization gates.
  10. Air Canada Rouge did not include autothrust-off approach scenarios in each recurrent simulator training module, and flight crews routinely fly with the automation on. As a result, the occurrence flight crew was not fully proficient in autothrust-off approaches, including management of the automation.

 Findings as to risk

  1. If flight crews do not conduct thorough briefings, including missed-approach briefings, they may not have a common action plan or set priorities, resulting in reduced crew coordination, which might compromise the safety of flight operations.
  2. If flight crews are distracted by other operational and non-operational activities and do not follow standard operating procedures, critical tasks associated with flying the aircraft may be delayed or missed.
  3. If flight crews do not adhere to standard procedures and best practices that facilitate the monitoring of stabilized approach criteria and excessive parameter deviations, there is a risk that threats, errors, and undesired aircraft states will be mismanaged.
  4. If an air operator’s standard operating procedures (SOP) are not consistent with its stable approach policy, there is a risk that flight crews will continue an approach while deviating from the SOPs, resulting in an unstable approach.
  5. If standards for flight crew training in relation to automation proficiency (Commercial Air Service Standards 725.124) are not explicit with regard to frequency, there is a risk that air operators will exclude critical elements from recurrent training modules and that flight crews might not be proficient in all levels of automation.

4.Safety action

Safety action taken

Air Canada Rouge conducted an internal safety management system (SMS) investigation into this occurrence and an assessment of its flight operations. In the course of the investigation, the company identified and took steps to mitigate the risks associated with portions of its flight operations, specifically unstable approaches. Air Canada Rouge has taken the following corrective actions:

  • It has incorporated simulator training for unstable approaches leading to a go-around into the syllabus for the recurrent training of flight crew. The intent is to incorporate the same training into the initial type training, but this action has not been completed yet.
  • It has modified the recurrent training syllabus to include more manual flying, including controlled flight into terrain (CFIT) recovery, steep turns, approach to stall, upset recovery, autothrust disconnection and reconnection, and operations with autothrust off.
  • It has implemented standard operating procedure (SOP) changes, which refined the company’s stable approach policy. The changes were developed based on consultation with Air Canada, the findings of the company’s internal investigation on this occurrence, and the latest proposals from the Flight Safety Foundation.
  • It has improved the annual recurrent training program, including new and/or improved modules on dealing with distractions on the flight deck; leadership and professional standards, focusing on open communication; and dealing with non-compliance with standard operating procedures by the other flight crew member.

Excerpted from Transportation Safety Board of Canada Aviation Investigation Report A14F0065 Unstable approach and hard landing, Air Canada Rouge LP Airbus A319, C-FZUG, Sangster International Airport, Montego Bay, Jamaica, 10 May 2014

FURTHER READING

  1. The Organizational Influences behind the aviation accidents & incidents

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minime2By Laura Duque-Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day 

 

Stress and lack of quality sleep, factors leading to serious incident

dash-8-flybe

Photo (C) Steve Morris

Final report published: 20 January 2017

Serious incident: An incident involving circumstances indicating that an accident nearly occurred. Note 1.— The difference between an accident and a serious incident lies only in the result… ICAO ANNEX 13 Chapter 1, Definitions.

Air Accident Investigation Unit Ireland

FACTUAL REPORT SERIOUS INCIDENT

Bombardier DHC 8-402 (Q400), G-ECOP

Dublin CTA near point VATRY. 27 April 2016 

Published: 20 January 2017

 AAIU Report No: 2017-002

State File No: IRL00916026

Report Format: Factual Report

Aircraft Type and Registration: Bombardier DHC 8-402 (Q400), G-ECOP

Date and Time (UTC)4: 27 April 2016 @ 14.16 hrs (Timings in this Report are quoted in UTC; to obtain local time add 1 hour )

Location: Dublin CTA5 near point VATRY (Reporting point at position N52 33.3’ W005 30.0)

Type of Operation: Commercial Air Transport

Persons on Board: Crew – 4 Passengers – 33

Injuries: Crew – Nil Passengers – Nil

Nature of Damage: None

SYNOPSIS

On a scheduled passenger flight, shortly before descent into Dublin (EIDW), the Co-pilot began to feel unwell and requested to leave the flight deck for a few minutes. Before the Co-pilot left his seat, the Commander felt an unexpected aircraft upset in the form of a yaw and roll to the left. The Co-pilot, who had become incapacitated, had inadvertently made an input to the left rudder pedal. The Commander returned the aircraft to normal flight and the aircraft landed without further incident. There were no injuries.

1. FACTUAL INFORMATION

1.1 History of the Flight

The aircraft departed Exeter Airport (EGTE) at 13.37 hrs on a scheduled flight to EIDW with 33 passengers, two flight crew members, a Senior Cabin Crew Member (SCCM) and a Cabin Crew Member (CCM) on board. On this sector, the Commander was Pilot Flying (PF) and the Co-pilot was Pilot Monitoring (PM). Having briefed the expected approach and completed the descent checklist, the aircraft was cleared to descend to FL150. As the aircraft entered the Dublin CTA at point VATRY, the Co-pilot made a request to leave the flight deck to use the lavatory. The Commander called the SCCM to attend the flight deck while the Co-pilot was absent. Following this call the seatbelt sign was switched on. After the call was completed the Commander felt the aircraft unexpectedly yaw to the left and rolled approximately 18 degrees. The Commander disconnected the autopilot, restored a wings level condition and retarded the engine power to maintain a stable descent. He then tried to ascertain what had caused the unexpected aircraft upset. The aircraft symbol showed at full deflection on the PFD Primary Flight Display so he checked for a possible runaway of the rudder trim but this indicated normal. Simultaneously, the SCCM called the flight deck to see if all was okay and the Commander told her to standby. Asking the Co-pilot for his opinion, the Commander then realised that the Co-pilot was unwell. The Commander stated that the Co-pilot had become incapacitated and was not responsive to verbal communication or physical stimulation for a period of less than one minute.

Having ensured that the aircraft was on a safe flight path, the Commander called the Cabin Crew for assistance. He then made a PAN (Urgency) call to Dublin ATC, informed them of pilot incapacitation and requested priority for an approach to Runway (RWY) 28. The SCCM proceeded to the flight deck and rendered assistance to the Co-pilot. It was decided that for the approach and landing that the CCM would occupy the crew jump-seat once she had secured the cabin for landing and that the SCCM would manage the cabin. They ensured that the Co-pilot’s seat was moved back from the controls and that his harness was locked.

The Co-pilot gradually recovered and was able to converse approximately five minutes after his initial symptoms arose. He did not take any further part in the conduct of the flight and declined therapeutic oxygen which had been made available by the Cabin Crew. With the CCM occupying the jump-seat, an able-bodied passenger (ABP) was briefed and occupied the CCM crew seat at the rear of the passenger cabin for landing.

Some holding delays were being experienced by inbound traffic at EIDW. However, ATC facilitated the flight with a direct routing and priority approach. The aircraft landed without further incident at 14.37 hrs and taxied to Stand 205L, where it was met by the Emergency Services. Paramedics immediately attended to the Co-pilot while the passengers remained seated. When the aircraft arrived on stand, the Co-pilot had recovered considerably; however, he was brought to a hospital in Dublin as a precaution.

1.2 Subsequent Events

The remainder of the Crew were stood down from subsequent duties and positioned home to the UK later that day.

The Co-pilot was kept in hospital overnight for observation before being released. It was determined that the Co-pilot suffered a brief loss of consciousness (syncope) due to a sudden drop in blood pressure. This condition can commonly occur in healthy people and recovery is normally prompt and without any persisting ill effects. At the time of writing, the Co-pilot had not yet returned to flying duties with the Operator.

1.3 Human Factors

Prior to the flight, the Crew positioned by taxi from their base at Southampton (EGHI) to EGTE. None of the other crew observed anything unusual about the Co-pilot that would highlight any form of medical issue, only that he seemed distracted due to the fact that his young child had a hospital appointment the following day. It was also reported that his recent sleep pattern had been disrupted.

1.4 Operator’s Safety and Emergency Procedures

The Operator prescribes the actions to be taken in the event of Pilot incapacitation in its Operations Manual Part B (Ops Part B), Safety and Emergency Procedures (SEP) and the aircraft’s Quick Reference Handbook (QRH). The procedure states that the flight crew may require assistance of a CCM to secure the seat and harness of the incapacitated flight crew member, administer oxygen if required and to occupy the flight deck jump-seat in order to assist with checklists. In this case, the CCM had some problems setting up the spare headset from the jump-seat position as the headset jack plugs had not been connected to the communications box nor was the microphone selected.

The event unfolded rapidly and consequently the Crew dealt with the situation without reference to the QRH or Ops Part B, SEP; however, the required elements of the relevant drills were covered. The Operator subsequently found that the QRH ‘Pilot Incapacitation’ checklist incorrectly referred to Ops Manual Part B, SEP Section 4-17 (the correct reference should have been Section 4-16).

Whilst the Operator monitored the developing situation, it did not activate its Crisis Management Centre (CMC). As part of its own investigation, the Operator chose to review the criteria used for activation of the CMC.

1.5 Personnel Details

1.5.1 Commander

The Commander was the holder of an Airline Transport Pilot Licence (Aeroplanes) issued by the UK CAA on 1 February 2013. This licence contained a Type and Instrument Rating on the DHC 8; he completed an Operator Proficiency Check (OPC) on 2 March 2016. His Medical Certificate (Class 1) was valid to 9 March 2017. At the time of the event, the Commander had 5,100 hours total flying time, of which 4,300 hours were on the DHC 8.

1.5.2 Co-pilot

The Co-pilot was the holder of an Airline Transport Pilot Licence (Aeroplanes) issued by the UK CAA on 2 March 2010. This licence contained a Type and Instrument Rating on the DHC 8; he completed an OPC on 17 December 2015. His Medical Certificate (Class 1) was valid to 27 April 2017. At the time of the event, the Co-pilot had 5,400 hours total flying time, of which 200 hours were on the DHC 8.

1.6 Crew Resource Management

Crew Resource Management (CRM) is an essential element in the operation of commercial aircraft. Both Flight Crew and Cabin Crew are trained in CRM procedures, which involve efficient crew co-ordination, effective communications, improved situational awareness and conflict resolution techniques. CRM optimises the use of all available resources, facilitating safe and effective operation of the aircraft.

1.7 Safety Actions by the Operator

As a result of this occurrence, the Operator conducted an internal safety investigation and undertook the following actions:

  • An amendment was made to the Q400 QRH, Page 8.7, with reference to ‘SEP Manual, Section 4.16’.
  • A review of its CMC activation criteria was carried out.
  • Cabin Crew Initial and Cabin Crew Refresher Training programmes were revised to include the use of the flight deck jump-seat headset.

2. AAIU COMMENT

The Co-pilot was probably under some stress on the morning of the flight considering that his young child had a hospital appointment the following day. Stress and lack of quality sleep may have been factors in his feeling unwell and incapacitation during the flight. In this event the Co-pilot requested permission to leave the flight deck at a time when the flight crew’s workload began to increase at the commencement of descent. Before the Copilot could leave the flight deck, the Commander responded to an unexpected aircraft upset caused by an involuntary input from the Co-pilot as he became increasingly unwell.

Following the unexpected aircraft upset, the Commander reacted promptly and ensured that the aircraft was returned to a safe flight path. Only then did he realise that the Co-pilot was unresponsive and had become incapacitated.

As the Commander was already in communication with the SCCM, he considered the standard call to alert Cabin Crew was not required. The Crew reacted to the situation in an effective and co-ordinated manner, carried out the incapacitation drills and the CCM occupied the jump-seat for approach and landing. Notwithstanding a minor issue with a headset, there was good communication between the Commander and Cabin Crew. The Commander, assisted by the Cabin Crew, ensured that the Co-pilot was secure in his seat and away from the controls while the cabin was secured for the approach and landing with an ABP occupying the aft crew seat.

The situation was dealt with in an efficient manner by the Commander with good use of CRM by the Crew; in its own safety report the Operator commented that ‘the reaction by the rest of the crew was swift and effective and they should be commended for their calmness, initiative and attitude throughout the incident.’

The Operator took action to correct some minor issues identified by its internal safety investigation. As a result, this Investigation does not make any Safety Recommendations.

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Stress and fatigue can affect pilot performance in many ways. Usually, we look at them and their effects in their chronic states. The cognitive and performance decrements due to chronic stress and sleep loss are very well and widely known. Nonetheless, as this case dramatically shows, the effects of acute stress and sleep loss should not be neglected. Special attention has to be given to high acute stress induced by family and life issues and its capacity to induce in-flight pilot incapacitation and/or negatively affect pilot performance.

This arises, again, the need and high importance of airline support and counselling services for flight crews to which the pilot can go freely without worrying about the decline in their income or the fear of reprisals from the airline.

Pilot in-flight incapacitation always has the potential to produce an aviation serious event.The safe operation of an aircraft places many demands on the pilot and crew. In order to meet these demands, a crew member requires good mental and physical health. The impairment of physical or mental capability, acute o chronic, has serious implications for the safety of flight.

FURTHER READING

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minime2By Laura Duque-Arrubla, a medical doctor with postgraduate studies in Aviation Medicine, Human Factors and Aviation Safety. In the aviation field since 1988, Human Factors instructor since 1994. Follow me on facebook Living Safely with Human Error and twitter@dralaurita. Human Factors information almost every day