TransAsia Airways Flight GE235 accident Final Report

Released on Jul 1st, 2016. Multiple organizational influences and technical and no-technical training deficiencies identified as contributing factors.

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Figure 1.12-9 14th frame of dashboard camera video (Excerpted from the Final Report- Use of the video was authorized by the TVBS)

Factual Information

History of Flight

On 4 February 2015, an ATR-GIE Avions de Transport Regional ATR72-212A (ATR72-600) aircraft, registered B-22816, TransAsia Airways flight GE 235, with three pilots, two cabin crew, and 53 passengers was being operated by TransAsia Airways (TNA) on an instrument flight rules (IFR) regular public transport service from Songshan to Kinmen. At 1054 Taipei Local Time, three minutes after taking off from runway 10, the aircraft impacted Keelung River, approximately 3 nautical miles (nm) east of Taipei’s Songshan Airport (Unless otherwise noted, the 24-hour clock is used in this report to describe the local time of day, Taipei local time, as particular events occurred. Taipei local time is Universal Coordinated Time (UTC) +8 hours.). The aircraft was destroyed by impact forces. Forty-three occupants, including three flight crew, one cabin crew, and 39 passengers were fatally injured. The remaining 13 passengers and one cabin crew sustained serious injuries. One passenger received minor injuries.

More than half of the main wreckage was submerged in the middle of the river (see Figure 1.1-1). As the aircraft flew over an overpass before impacting the water, its left wing collided with a taxi with two occupants. The taxi driver sustained serious injuries and the passenger sustained minor injuries.

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Figure 1.1-1 GE235 main wreckage

On the day of the occurrence, the flight crew was assigned to operate two return flights from Songshan to Kinmen. The four sectors were allocated two operating captains and a first officer acting as an observer. The first sector (GE231) from Songshan to Kinmen departed at 0744 and arrived at 0850 without incident. The return sector (GE232) departed Kinmen at 0917 and arrived at Songshan at 1012 was also uneventful.

The third sector (GE235), which was the occurrence flight, was scheduled to depart Songshan at 1045. Captain A, who was the pilot-in-command (PIC), occupied the left seat and was the pilot flying (PF) for the takeoff, while Captain B occupied the right seat and was the pilot monitoring (PM). The first officer occupied the cockpit jump seat as an observer pilot (OBS).

According to the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) data, GE235 took off from Songshan runway 10 at 1051 in accordance with the MUCHA 2 Quebec standard instrument departure (SID) procedure bound for Kinmen. The takeoff roll commenced at 1051:39. Four seconds later (1051:43), the PM mentioned that the automatic take off power control system (ATPCS) was not armed. The PF responded with “really” (Content in italics is quoted from CVR transcript and may contain translation from Mandarin language) and then said: “ok continue to take  off”. The PM replied: “we will continue”. Seven seconds later, the PM stated “oh there it is ATPCS armed”, and then the aircraft became airborne at 1052:01. The landing gear was retracted after achieving a positive rate of climb. The aircraft accelerated and continued to climb. The crew selected an altitude of 5,000 feet (ALT SEL 5,000) and airspeed of 115 knots on the autopilot (The speed described in this report is computed air speed). The left coupling autopilot was engaged with lateral navigation (LNAV) and indicated airspeed (IAS) modes. At 1052:34 the Songshan tower controller instructed the GE235 flight crew to contact Taipei Approach while the aircraft was commencing a right turn and climbing through an altitude of 1,000 feet (Unless otherwise noted, the altitude of the aircraft described in this report is radio altitude).

At 1052:38, when the aircraft was continuing the right turn and climbing through 1,200 feet, the FDR indicated that engine number 1 (ENG 1) was operating in an up trim condition with its bleed valve closed. That corresponded with the beginning of an ATPCS sequence, which included the auto feathering  of the engine number 2 (ENG 2) propellers (Feathering of the propeller is where the propeller blades are rotated parallel to the airflow to reduce drag   in case of an engine failure). The master warning (MW) annunciated in the cockpit and the ENG 2 propeller pitch angles started to advance to the feather position accompanied by the indication of the “ENG 2 FLAME OUT AT TAKEOFF” procedure on the engine warning display (EWD).

At 1052:41, the autopilot was disconnected as the aircraft climbed through an altitude of 1,300 feet. Three seconds later at 1052:44, the ATPCS sequence ended and the ENG 2 propeller was fully feathered. At 1052:43 the PF stated: “I will pull back engine one throttle”. The PM responded “wait a second cross check”, but the ENG 1 power lever angle (PLA6) had already been retarded from 75 degrees to 66 degrees (The PLA signal is from mechanical fuel control unit (MFCU) angle and is recorded on the FDR). The PF and PM then both announced heading mode and continued the flight. At 1052:51, the aircraft was climbing through 1,485 feet at 106 knots, with a heading of 131 degrees. The automatic flight control system (AFCS) indicated that HDG SEL and IAS mode were selected. At 1052:57, the selected heading was altered to 092 degrees and the aircraft then started turning to the left at an airspeed of 106 knots.

At 1053:00, the PM stated: “okay engine flame out check”. The PF responded “check” and the PM stated: “check up trim yes, auto feather yes”. At 1053:05 the PF responded “okay”. At almost the same time, the PM stated “watch the speed” because the indicated airspeed had reduced to 101 knots. The PF then announced ”pull back number one”, and the ENG 1 PLA was retarded to 49 degrees. While the ENG 1 power lever was retarded, the PM said “okay now number two engine flameout confirmed”, and the PF responded “okay” but the ENG 1 PLA still remained at 49 degrees.

At 1053:09, the aircraft had climbed to 1,630 feet, which was the highest altitude recorded for the occurrence flight. The indicated airspeed was 102 knots. The AFCS IAS mode then reverted into PITCH HOLD mode and one second later the stall warning annunciated in the cockpit for one second (According to the ATR, the ATR72 IAS mode has two different sub-modes: take off sub-mode and cruise sub-mode. The two sub-modes are the guidance system internal logics. The IAS take off sub-mode is engaged two seconds after lift-off and replaced by IAS cruise sub-mode three minutes after lift-off. The IAS take off sub-mode guidance primarily maintains the IAS target but also ensures a minimum ascending slope. The minimum ascending slope is monitored by a “flight path angle (FPA) protection term” which is compared to the “IAS control term”. The FPA protection term becoming greater than the IAS control term means that the airplane has no sufficient energy to continue climbing with that minimum slope at the selected airspeed. If this condition is met for 20 seconds, the IAS mode automatically disengages and reverts to PITCH HOLD mode). The PF then stated “terrain ahead” and the PM replied “okay lower…” and the OBS said “you are low”. At 1053:13 the stall warning sounded for four seconds and the stick shakers activated (The stick shaker was part of the aircraft’s stall warning system, and indicated to the crew when the aircraft was approaching an aerodynamic stall by activating electrical motors that caused both pilots’ control columns to vibrate rapidly). The PM stated “okay push, push back”, to which the PF stated “shut”. The PM responded “wait a second…throttle throttle”.

Between 1053:13 and 1053:15, the ENG 2 PLA was advanced to 86 degrees and the ENG 1 PLA was retarded to around 34.5 degrees (idle position). At 1053:18, the aircraft was heading 087 degrees but in a continuous left turn with a 10 to 20-degree angle of bank, descending through 1,526 feet at an airspeed of 101 knots. At 1053:19 the PF said “number one” followed by “feather shut off”. The PM called “number feather”, and then the stick shakers and stick pushers  activated several times until 1053:27 (In the event of an aerodynamic stall, the aircraft was equipped with a stick pusher that automatically decreased the aircraft’s angle-of-attack). At 1053:24, the FDR indicated that the ENG 1 condition lever was in the fuel shut off position, and six seconds later the ENG 1 propeller had attained the feathered position. The aircraft’s indicated airspeed was 110 knots at an altitude of 1,165 feet and descending.

At 1053:35, the PM declared an emergency (Mayday) to air traffic control (ATC). The aircraft was heading 050 degrees and had commenced banking to the right. From 1053:46 to 1054:04, the flight crew tried to engage the autopilot twice, but they did not succeed. At 1053:53, the OBS said: “how come it becomes like this”. At 1054:05, the PM stated “both sides…lost” and two seconds later the PM realized and stated “no engine flameout we lost both sides”. At 1054:09, the PF stated “restart the engine”, when the altitude was 545 feet with an airspeed of 105 knots. He subsequently repeated “restart the engine” seven times.

At 1054:20, the ENG 1 condition lever was moved out of the shut-off position and at 1054:25, the ENG 1 high-pressure speed (NH1) increased to 30%. The aircraft’s altitude and indicated airspeed at that time were 400 feet and 106 knots respectively. The aircraft also started to bank to the left. At 1054:27, the PF said: “wow pulled back the wrong side throttle”. From that time on, the aircraft entered an aerodynamic stall from which it did not recover.

At 1054:34, the enhanced ground proximity warning system (EGPWS) “pull-up” warning was annunciated in the cockpit. At 1054:35 the aircraft’s left bank angle increased from 10 to 80 degrees. The aircraft’s left wing then collided with a taxi driving on the overpass. The wing then impacted the fence and a light pole at the edge of the overpass located southwest of the Keelung river occurrence site (see Figure 1.1-2). The aircraft continued to bank to the left after those collisions and then entered the river inverted.

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Figure 1.1-2 GE235 loss of control and initial impact sequence. To watch the accident videohttp://www.liveleak.com/view?i=e36_1423052703

Personnel Information

Flight Crew Background and Experience

Captain A

Captain A, a Republic of China citizen, had served in the Air Force as a pilot. After retiring from the Air Force, he joined a local airline in September 2009 where he undertook Airbus A330 transition training between September 2009 and March 2010. He did not complete the training successfully because he was unable to meet the airline’s pilot performance standards and requirements. He subsequently left the airline in March 2010.

Captain A then joined TNA in August 2010 where he successfully completed initial training on the ATR72-500 in February 2011 and subsequently served as a first officer on the ATR72-500 fleet. In August 2014, he completed ATR72-500 command upgrade training and was promoted to captain. In November 2014, he completed differences training and was transferred to the ATR72-600 fleet as a captain.

As of the date of the occurrence, he had accumulated 4,914 total flight hours, including 3,151 hours in the ATR72-500, and approximately 250 hours in the ATR72-600.

Captain A held an air transport pilot license (ATPL) issued by the Civil Aeronautics Administration (CAA) with a multi-engine land, instrument, and type rating on both ATR72-500/600, endorsed with privileges for the operation of radiotelephone on board an aircraft with no limitations and a current ICAO Level 4 English language proficiency.

Captain B

Captain B was a Republic of China citizen. He joined TNA in June 2006. He successfully completed first officer training in August 2007 and served as a first officer on the ATR72-500 fleet. He successfully completed command upgrade training in September 2011 and was promoted to captain. In February 2014, Captain B completed ATR72-600 differences training and was transferred to the ATR72-600 fleet as a captain.

As of the date of occurrence, he had accumulated 6,922 total flight hours, including 5,687 hours on the ATR72-500 and 795 hours on the ATR72-600.

Captain B held an air transport pilot license (ATPL) issued by the CAA witha  multiengine land, instrument, type ratings on the ATR72-500/600, endorsed with privileges for the operation of radiotelephone on board an aircraft with no limitations and a perpetually valid ICAO Level 6 English language proficiency.

First Officer

The first officer, a Republic of China citizen, joined TNA in October 2008. He successfully completed ATR72-500 transition training in November 2009 and served as a first officer on the ATR72-500 fleet. In January 2015, he commenced ATR72-600 differences training and was still under training on the date of the occurrence. The first officer had previously flown McDonnell Douglas MD-82 aircraft at another airline before joining TNA.

As of the date of occurrence, he had accumulated 16,121 total flight hours, including 7,911 hours on the MD-82, 5,306 hours on the ATR72-500, and 8 hours on the ATR72-600.

The first officer held an air transport pilot license (ATPL) issued by the CAA with a multiengine land, instrument, type ratings on the ATR72-500/600 and MD-80s, endorsed with privileges for the operation of radiotelephone on board an aircraft limited to first officer on the ATR72-500/600 and a current ICAO Level 4 English language proficiency.

Flight Crew Training Record

Captain A

Initial Training in Previous Airlines

Captain A received A330 initial transition training from September 2009 to March 2010. During the training process, an additional 14 hours of ground school, 8 hours on the MFTD (MFTD: maintenance/flight training device), 2 oral tests, 1 interview, and 3 TRBs (TRBs: technique review boards)  were conducted to address the pilot’s skill and knowledge deficiencies identified during training. In addition, given the pilot’s training performance, four instructors requested that the pilot undertakes remedial training during the simulation phases (FBS FBS: fixed based simulator   and FFS: FFS: full flight simulator).

Captain A could not meet the airline’s pilot performance standards and requirements despite the additional remedial training. The flight training department subsequently decided to discontinue his training on 30 March 2010.  The concluding training report noted the following areas of concern:

  • Multi-Tasks handling/management ability was not able to catch flight progress, left behind aircraft was observed from time to time;
  • Insufficient situational awareness and confidence. Unable to prioritize and make correct decisions in both normal and abnormal situation; and
  • Lack of resistance to stress. Unsteady performance under high workload situations. Unable to handle multi-task at the same

Initial Training in TNA

Captain A received ATR72-500 initial training from 16 August 2010 to 18 February 2011. He successfully completed the initial training and passed the first officer line check on 4 March 2011.

Upgrade Training

Captain A commenced ATR72-500 command upgrade training on 14 April 2014. He passed the ground school and simulator training but failed the simulator check on 31 May 2014 with the following unsatisfactory items: “ABNORMAL ENG START”; “BOTH HYD SYS LOSS”; and “S/E APP GO AROUND”. The

check airman’s comments included:

  • Incomplete procedure check and execution;
  • Insufficient knowledge of QRH (ENG FLAME OUT AT T/O, BOTH HYD SYS LOSS);
  • Did not fully advance power levers to ramp position during the SINGLE ENGINE APP GO AROUND;
  • Did not follow SOP for ENG FIRE operation while on short final and altitude below 400 feet; and
  • Cockpit management and flight planning needs

A technical review board (TRB) to discuss the pilot’s performance was convened on 19 June 2014. The TRB decided to provide Captain A an additional simulator session followed by a simulator re-check between 29 and 30 June 2014. The additional simulator training session was conducted by the Flight Operations Department’s (FOD) Assistant Vice-President who was a senior instructor pilot (IP). As a qualified senior check pilot (CP), the company’s ATR Chief Pilot conducted Captain A’s re-check. Captain A successfully completed the additional simulator training session and subsequently passed the simulator check. He was promoted to captain on 1 July 2014.

Captain A then completed line training from 2 July to 10 August 2014. Evaluations of the pilot’s performance by the IPs delivering the line training included:

  • Prone to be nervous and may make oral errors during the engine start procedure;
  • Insufficient knowledge leading to hesitations in “Both EEC Failure” and “Engine Failure after V1” situation during the oral test;
  • Lack of confidence and being nervous while answering the Smoke procedure during the oral test;
  • Incomplete check and execution of certain procedures;
  • Hesitant when facing situations that require making decisions; and
  • Flight planning should be

Differences Training

Captain A attended a one-week ATR72-500/600 differences training course at the ATR Training Center in Singapore from 27 to 31 October 2014. That training comprised ground training and simulator training. The associated line training was undertaken at TNA.

The assessment of the pilot’s performance during the virtual hardware  platform (VHP) trainer sessions in the first 4 days were “Progress is Normal” with instructors’ comments of “Good Job”. However, the assessment of the pilot’s performance during the full flight simulator (FFS) session on the final day of training noted that the pilot “MAY NEED extra training” commenting “check EFATO (EFATO: engine flame out at take off. Also known as an engine failure after takeoff) call out and Task sharing and Go Around  Single Engine” (The ATR stated that the ‘’MAY NEED extra training’’ is used when an instructor wants to reinforce his opinion before validating a specific task or competence. This can be done by another instructor or himself during the next normal session or test (no extra training time required at this step). There are 2 possibilities after a ‘’May need extra training’’ assessment: Either the same or another instructor is satisfied with the performance demonstrated later and no extra training is required, or the second demonstration is showing a weakness and then some extra training time is required with an instructor).

Captain A passed the ATR72-600 simulator check and was authorized to captain the ATR72-600 aircraft on 2 November 2014. The areas for improvement that were previously identified were assessed again during the simulator check and the pilot’s performance was found to be ”Satisfactory” – ”all STD” (STD: standard. That is, the pilot met the required performance standard). He subsequently passed the ATR72-600 line check on 11 November 2014 and began operating as an ATR72-600 captain.

Recurrent Training

Captain A’s most recent annual proficiency training and checks were consolidated with his command upgrade and differences training conducted in 2014. The records indicated that the pilot had passed the required checks.

Captain B

Initial Training

Captain B commenced ATR72-500 first officer initial training on 22 March 2007. That training comprised six phases: phase one “basic ground training”; phase two “airplane type ground training”; phase three “observation flights”; phase four “simulator training”; phase five “local training”; and phase six “initial operating experience (IOE) line training”. He completed the initial training successfully on 14 August 2007 and qualified as an ATR72-500 first officer. No items of concern were noted in Captain B’s first officer training records.

Upgrade Training

Captain B commenced ATR72-500 command upgrade training on 27 June 2011. That training comprised ground training, simulator training, and line training. He completed upgrade training successfully on 3 September 2011 and qualified as an ATR72-500 captain. There were no areas of concern noted during Captain’s B command upgrade training.

Differences Training

Captain B commenced ATR72-600 differences training on 16 December 2013 at the ATR Training Center in Singapore. That training comprised ground training and simulator training. The associated line training was undertaken at TNA. He successfully completed the differences simulator check on 21 December 2013. The comment from the JAA 18 certified examiner was “Standard Session”. The subsequent line check was conducted successfully on 25 February 2014. The comment from the JAA certified examiner was “Good Job, Satisfactory”. There were no other significant comments regarding these checks.

Recurrent Training

Captain B completed eight hours of annual recurrent ground training on 4 December 2014. The training syllabus comprised adverse weather operations, normal/abnormal procedures, including the roles of PF/PM and other flight crew task sharing, positive transfer of aircraft control, consistent checklist philosophy, emphasis on the priorities of “aviate, navigate, communicate”, correct use of all levels of flight automation, correct crew response to system malfunction/s, and aircraft type systems and limitations.

Captain B’s most recent proficiency training (PT) was conducted on 6 December 2014. The training syllabus included stall recovery, unusual attitude recovery, and engine flame out at take off. The JAA certified IP assessed Captain B’s performance as “Satisfactory, Good Job”.

Captain B’s most recent proficiency check (PC) was conducted on 7 December 2014. The pilot passed the check. Captain B’s evaluation was annotated with “aircraft maneuvering and procedures are conducted in accordance with standards, general handling of emergency, general CRM”. The most recent line check was consolidated with the differences line check, which was successfully completed on 25 February 2014.

First Officer

Transition Training

The first officer (FO) had experience as an MD-82 captain with his previous airline. TNA hired him as a first officer for the ATR72.

The FO commenced ATR72-500 transition training on 16 June 2008. The training syllabus included ground training, line observation training, simulator training, local training, and line training. The FO failed his first ATR72-500 simulator check. The examiner commented that he “Could not properly identify abnormal engine start. Not properly handle standard callouts, engine flame out, engine fire, and go around.”

After undertaking remedial training, the FO subsequently passed the simulator check on 19 September 2008. He completed ATR72-500 transition training on 8 November 2008 with a satisfactory line check.

Recurrent Training

The FO completed eight hours of annual recurrent ground training on 12 September 2014. The training syllabus comprised adverse weather operations, normal/abnormal procedures, including the roles of PF/PM and other flight crew task sharing, positive transfer of aircraft control, consistent checklist philosophy, emphasis on the priorities of “aviate, navigate, communicate”, correct use of all levels of flight automation, correct crew response to system malfunction/s, and aircraft type systems and limitations.

The FO’s most recent proficiency training and check were conducted on 17 and 18 September 2014 respectively. The training syllabus included stall recovery, unusual attitude recovery, and engine flame out at take off. The FO’s training performance was assessed as “Satisfactory” and he passed the subsequent check. The FO also passed his most recent annual line check on 26 November 2014.

Differences Training

The FO commenced ATR72-600 differences training on 12 January 2015 at  the ATR Training Center in Singapore. That training comprised ground training and simulator training. The associated line training was undertaken at TNA.

While he passed the differences simulator check on 19 January 2015, the examiner commented that the FO “will need some time to get used to the 600 (ATR72-600), flying with an experienced captain is strongly recommended.”

As  at the date of  occurrence, the FO was  still  undergoing ATR72-600differences line training. The occurrence flight was an observation flight for the FO.

Flight Recorders

The flight data recorder (FDR) and the cockpit voice recorder (CVR) were recovered by the ASC investigators at 1605 on the occurrence day. Both recorders were immersed in water but exhibited no external damage. The recovered CVR and FDR are shown in Figure 1.11-1.

Both recorders were transported to the ASC Investigation Laboratory for disassembling and readout on 4 February. The crash survival memory units (CSMU) of both the CVR and FDR were in good condition. After cleaning and drying the CSMUs, data from both recorders were successfully downloaded.

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Figure 1.11-1 External view of the FDR and CVR

Other Flight Data and Radar Track Data

Flight Path Reconstruction

Figure 1.11-5 illustrates the aircraft’s GPS flight path, ATC radar track, and key warnings in the cockpit superimposed on a satellite photo of the area. The GE235 flight path, satellite image and key events between 1053:07.7 and 1053:59.7 and the last 23 seconds of the flight are presented in Figures 1.11-6 and 1.11-7 respectively.

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Figure 1.11-5 Superimposed GE235 GPS flight path, ATC radar track and key cockpit warnings

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Figure 1.11-6 GE235 flight path and key events rendered on a fused satellite image and digital surface model between 1053:07.7 and 1053:59.7

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Figure 1.11-7 GE235 flight path and key events rendered on a fused satellite image and digital surface model for the final 23 seconds of flight

Figure 1.12-5 presents an aerial photograph of the accident site. Keelung River is to the north side of the overpass. The depth of the river in this location is between one to two meters.

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Figure 1.12-5 Aerial Photo of the GE235 crash site

Figure 1.12-6 illustrates the aircraft’s final trajectory and impact location.

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Figure 1.12-6 Aircraft’s final trajectory and impact location

Analysis of findings

General

The flight crew were properly certificated and qualified in accordance with applicable Civil Aviation Regulations, Republic of China. There was no evidence to indicate that the flight crew’s performance might have been adversely affected by pre-existing medical conditions, fatigue, medication, other drugs or alcohol during the occurrence flight. Visual meteorological conditions (VMC) prevailed at the time of the aircraft’s departure. No adverse weather conditions were present for the flight. The analysis addresses safety issues associated with aircraft airworthiness, flight operations, including crew training, and human factors issues, such as crew resources management.

The GE222 investigation had identified specific areas for improvement in the TNA’s safety management processes and effectiveness of CAA’s regulatory surveillance activities so they will not be discussed further in this analysis. Those safety issues were still being addressed at the time of the GE235 occurrence.

Airworthiness

Aircraft Systems and Powerplant

The aircraft’s certificate of airworthiness and registration were current at the time of the occurrence. The occurrence aircraft was dispatched at Songshan Airport with no known defects and was in compliance with all applicable Airworthiness Directives and Service Bulletins. A review of the aircraft’s maintenance records before the occurrence flight revealed that there were no defects reported that related to ENG 2 automatic feathering system.

The wreckage examination indicated that the aircraft damage was the result of impact forces. Post-impact examination of the engines indicated no pre-existing anomalies affecting their normal operation. However, the CVR and FDR data indicated that ATPCS- Automatic Takeoff Power Control System  had not armed during the initial stage of the takeoff roll but then indicated that it had armed later in the take off roll. During the initial climb, an uncommanded autofeather of the ENG 2 occurred.

The ATPCS, AFU – Auto Feather Unit , and related components were examined and tested. Torque signal continuity relevant items including wiring harnesses and torque sensors were also checked . The continuity of wiring harnesses were checked normal. Among the four torque sensors that were examined, the left torque sensor of ENG 2 which connected to AFU No.2 was found a coil winding open circuit. (Each engine contained two torque sensors, the No. 1 (left) and No. 2 (right) sensor. The left torque sensor is connected to the AFU and the right torque sensor is connected to the EEC). The X-ray analysis of the sensor indicated that the coil wires had broken at the outside of the bend due to the impact.

The AFU examination results indicated that the compromised soldering joints inside ENG 2 AFU which formed part of the connection between ENG 2 torque sensor and the AFU No.2 had increased an unstable signal path resistance, therefore, may have produced an intermittent discontinuity of the torque signal. Continuity of the signal was required to ensure that the ATPCS system functioned as expected. The disrupted signal probably resulted in the uncommanded autofeather.

ATPCS and Uncommanded Autofeather

The purpose of the ATPCS was to automatically feather the propeller during takeoff in the case of engine failure, and then increase engine power (uptrim) to the opposite operating engine. The ATPCS monitors both engine torque signals, when one engine decreased below 18.5 percent rated torque it indicates the engine failure. Arming of the ATPCS also required that torque signal on both engines was greater than 46%. The operation of the ATPCS would be rendered unreliable if the torque signals transmitted to the system were disrupted intermittently or otherwise.

Post-impact testing of AFU No.2 revealed that the resistance exceeded the CMM threshold. The measured resistance values for pins J and H, which were the connecting points between the torque sensor and AFU, fluctuated and were higher than the prescribed values in CMM when the ribbon was moved by hand. Intermittent signal discontinuity produces an unstable torque signal to AFU and can adversely affect the functioning of the ATPCS, including unreliable arming and inadvertent or uncommanded autofeathering.

At time 1051:43 as recorded by the CVR, the flight crew announced that the ATPCS was “not armed” at take off power initiation. However, the FDR data indicated that all the conditions required for arming the ATPCS had been met. The abnormal status can be explained by the discontinuity between the AFU No.2 and the torque sensor. The discontinuity interrupted the torque signal path to the AFU and caused the ATPCS to indicate that it was not armed. Eight seconds later (1051:51), as recorded by the CVR, the flight crew announced that the ATPCS was now ARMED. This symptom was consistent with a temporary discontinuity that persisted for about eight seconds. During the climb through 1,200 feet, as recorded by the CVR and FDR, the master warning sounded associated display of the “ENG 2 FLAMEOUT AT TAKE OFF” procedure, the ATPCS autofeather sequence completed, leading to the uptrim of ENG 1 followed by the feathering of the ENG 2 propeller. However, all of ENG 2’s parameters were normal before the ATPCS sequence was triggered. This symptom was also consistent with a temporary discontinuity between the AFU No.2 and the torque sensor. The technical events that contributed to the occurrence were all consistent with intermittent discontinuity in the AFU No.2.

The intermittent discontinuity of AFU No.2 produced the unstable behavior of the ATPCS which resulted in the uncommanded autofeather of the ENG 2 propeller.

Autofeather Unit Quality

A few days after the GE235 occurrence, another TNA ATR72 crew experienced an uncommanded autofeather in-flight. That aircraft’s AFU (referred to as AFU No. 3) was removed and sent to the manufacturer for test and examination. The results revealed a similar discontinuity problem as found in AFU No.2.

The serial numbers of AFU No.2 and AFU No.3 were RT2362 and RT2354 respectively. The date of manufacturing of these two AFUs was in the same week, the fifteenth week of 2013. The AFUs had been in service since March 2014 and April 2014 respectively and the service periods  were less than one year. The similar compromised soldering joints were found in these two units (According to the TNA, the service period of AFU SN RT2362 was from 28 March 2014 to 4 February 2015, SN RT2354 was from 8 April 2014 to 21 February 2015).

The engine manufacturer (P&WC) had been aware of AFU-related technical issues causing uncommanded autofeather events since 2005 and proposed SBs starting from 2007. Investigation of the AFUs from those events revealed that some of the units exhibited cracks in the soldering of the J1 and J2 connectors. Those cracks were believed to have caused momentary electrical disruptions leading to an uncommanded autofeather. In response, the manufacturer issued various service bulletins and service information letters to operators recommending unit modification and/or information to address the AFU-related autofeather events.

SB No.21742 advised that “Aging of the Autofeather Unit (AFU) electrical connectors and interconnect ribbon solder joints can lead to loss of torque signal”. The manufacturer recommended implementing the service bulletin actions before the AFU had accumulated 12,000 flight hours, or before 31 July 2010, whichever occurred last. SIL No. PW100-138 and PW100-147 provided further information regarding the converter inspection, installation and soldering to its mounting board. In addition, AFU testing requirements were improved via testing at different temperatures (low, high and ambient) and vibration testing. These new instructions supplemented the revised instructions introduced for the J1 and J2 connectors and interconnect ribbons testing and inspection. The above maintenance actions were included in the latest CMM version.

With reference to Table 1.16-2, the total flight times of both AFU No.2 and AFU No.3, were 1,624 flight hours and 1,206 flight hours respectively. Compared to the engine manufacturer’s recommended inspection time of 12,000 flight hours, these two AFUs’ had accumulated time far below the manufacturer’s inspection recommendation. This suggested that the causes of intermittent continuity failure of the AFU may not only be related to aging, but also to other previously undiscovered issues. The current technical countermeasures implemented by the engine manufacturer to address the AFU continuity problems were not sufficiently effective and require further solutions. During this occurrence investigation, the engine manufacturer, Pratt & Whitney Canada, informed the investigation team that a product improvement was made to the auto-feather control and is currently implemented into all new production engines. Also, for the existing engines in service, a Service Bulletin, SB21880 (see Appendix 13), was issued in October 2015 to replace the auto-feather control with the improved one.

Flight Operations

ATPCS Policy and Procedures

After the brakes were released and both power levers were ‘SET IN THE NOTCH’ and ‘FMA (flight mode annunciator)  was announced and checked, the TNA ATR72-600 take off standard operating procedures required CM2 (crew member 2) to check then announce ‘ATPCS ARM’. As the throttle was advanced for take off in the occurrence flight, Captain B (PM) noticed that the ATPCS was not armed and he responded correctly by announcing that. The PM then announced ‘take off inhibit” which was confirmed by Captain A (PF) who then decided to continue the take off with the assent of the PM. The CVR indicated that the PM announced that the ATPCS had armed about seven seconds before the aircraft reached V1 speed.

TNA’s ATR72-500 fleet policy permitted flight crews to continue the take off if the ATPCS pushbutton ‘ARM’ light did not lit as long as RTOW had been checked before takeoff and the operation of the aircraft was modified in accordance with the procedures promulgated by company technical circular No. m1010604x issued in 2012.The TNA flight crew training supervisor informed the investigation that those technical circulars only applied to the -500 aircraft not the -600 aircraft. The company’s ATR72-600 policy required crews to reject the take off if the ATPCS did not ‘ARM’ and crews were trained to perform this procedure. In addition, the ATR72-600 pilots (including IPs, CPs, captains and first officers) who were interviewed also stated that they would abort the take off in such circumstances.

The occurrence flight crew’s decision was not consistent with these expectations. However, there were no documented company policies, instructions, procedures, or notices to crew for ATR72-600 operations communicating the requirement to reject the take off if the ATPCS did not arm. On the contrary, TNA’s ATR72-600 normal check list still required flight crew to check if the aircraft’s MTOW was below the RTOW before take off because that was the criterion for determining if a takeoff could be continued in the event of the ATPCS not arming. That may have indicated to -600 flight crew that the -500 ATPCS take off procedures in the event of the ATPCS not arming could apply. That discrepancy and potential for confusion had not been identified before the occurrence flight.

As of the date of the occurrence, Captain A and B had accrued 250 and 795 fly hours on the ATR72-600 respectively. They had previously accrued 3,151 and 5,687 fly hours on the ATR72-500 respectively. They were comparatively new to the -600. It was possible that their practices on the -500 fleet had transferred across to operating the -600. However, there was no evidence the occurrence flight crew reverted substituted other -500 procedures before or after the ATPCS not arming. Therefore, it seemed more likely that the absence of a formal, documented company policy that was enforced and consistent with the reported ATPCS training on the -600 created an opportunity for misunderstanding.

The  aircraft  manufacturer  issued  two  OEBs,  “Uncommanded   auto-feather -500” and “Uncommanded auto-feather -600” after the GE235 occurrence. Both OEBs promulgated the same normal take off procedure for ATPCS discrepancies: “At take off, the ATPCS must be checked armed and announced. If it is not armed while both power levers are in the notch, or in the case of intermittent arming / disarming of the ATPCS, the take off must be rejected.” These two OEBs would have provided a clear directive to TNA that all ATR72-500/600 crews were to reject the take off if they encountered any ATPCS discrepancies.

With reference to TNA ATR72-600 MEL, item 22-2, the ATPCS may be inoperative provided operations were conducted in accordance with the airplane flight manual supplement 7_02.10: “dispatch with ATPCS off”. According to that procedure, the first item was to select ATPCS OFF and bleed valves OFF, which disabled the autofeathering function during take off. Had the pilots rejected the take off in response to the ATPCS not arming, and then re-dispatched the aircraft with “ATPCS OFF” as per the MEL procedure, the subsequent uncommanded autofeather would not have occurred.

ATR Rejected Take off Policy

During the investigation, the ATR provided a statement of the SOP policy regarding the checks performed during take off and focus on ATPCS checks. The ATR stated that the purpose of the Standard Operating Procedures (SOP) is to ensure the aircraft is in the appropriate configuration for   all phase of flight, including take-off. By definition, any check not completed halts the procedure and take off cannot proceed. This is the industry norm. The ATR also provided an Airbus 3xx SOP at take off to show how another manufacturer deals with SOP. It is noted that Airbus does not list all the conditions leading to a rejected take off but write the general policy as an operating technique. However similar information was not documented in ATR’s manuals. The implementation of such information or policy announcement in the manufacturer FCOM is required so that a rejected take off procedure may be clarified.

Furthermore, although ATR72 AFM 5.03 has a rejected take off procedure described as an abnormal procedure, it is associated with one engine inoperative condition only, and the rejected take off procedure was not described in the ATR FCOM. It is required to review the manufacturers AFM to ensure that a rejected takeoff procedure is applicable also to both engine operating and should be described as an abnormal procedure in the FCOM.

Handling of Emergency Situation

Failure Identification

At 1052:38.3, when the aircraft commenced the right turn and was climbing through 1,200 feet, the master warning light / sound annunciated in the cockpit and the “ENG 2 OUT” red message was displayed on the Engine and Warning Display (EWD). According to TNA’s ATR72-600 Abnormal and Emergency SOPs, section 26.1, flight crews were advised to “take all necessary time to analyze situation before acting.” With reference to procedures initiation, the ATR72-600 Flight Crew Operating Manual (FCOM) advised that “Before performing a procedure, the crew must assess the situation as a whole, taking into consideration the failures, when fully identified, and the constraints imposed.” The priorities were to stabilize the aircraft’s flight path and assess the remaining aircraft capabilities.

TNA’s ATR72-600 Abnormal and Emergency SOPs provided a failure identification process to assist crews. In response to a “MASTER WARNING/CAUTION” Captain B, as the PM, was to announce the flashing master warning and call out the item flashing on the EWD. That meant that the required initial actions by the PM in the occurrence should have comprised calling ‘MASTER WARNING” and ‘ENGINE 2 OUT ON FWS” (flight warning system.)” followed by cancellation of the master warning and then announcing the fault or type of event on the systems display page. Captain A, as the PF, was then required to call “Check” after he had acknowledged the failure and when able to call out “SYSTEM CHECK”. Six failure analysis checks must be performed for failure confirmation after the PF calls ‘SYSTEM CHECK’. However, the CVR transcript and FDR readout indicated that following the master warning, the PM said “take a look”. Just as the PM began the failure identification process, approximately 4 seconds after the master warning occurred, the PF retarded the ENG 1 power lever (PL1) to a power lever angle (PLA) of 66.4 degrees and then said “I will pull back engine one throttle”. This was consistent with the PF assessing the situation and responding without any input from the PM as per the documented failure identification and confirmation process. Those hasty actions resulted in the cancellation of the uptrimmed power on ENG 1 which reduced the engine’s torque from its highest value of 104% to 82%.

The flight crew failed to perform the appropriate failure identification procedure before the PF reduced power on the operative engine. This premature action led to confusion in the cockpit. The PM called for a cross check and an engine flame out check but the PF did not address those items. The PM subsequently called an auto feather and confirmed that ENG 2 flameout but the PF had already retarded PL1 to 22% torque. The aircraft stall warning system then activated and then confusion was prevalent as the PF called the shutdown of ENG 1. By the time the PM announced engine flameout on both sides and an engine restart was attempted, the aircraft was at an altitude from which recovery was not possible and a stall and loss of control followed.

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Figure 1.6-4 Simulated EWD indications for ENG 2 autofeather at takeoff 

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Figure 1.6-5 Simulated EWD indications for  and “FLAME OUT AT TAKEOFF” procedure  

Utilization of Autopilot

TNA’s ATR72-600 Abnormal and Emergency SOPs stated that “unless the emergency or abnormal procedure directs the pilot to disconnect the auto flight system, it is recommended that it be used as much as possible during these situations”. The ATR72-600 FCOM also indicated that use of autopilot is recommended in order to reduce crew workload and increase safety.

The FDR indicated that the autopilot was engaged at 1052:16 and it was still engaged when the master warning occurred. The CVR indicated that one second after the master warning sounded, Captain A (PF) called out “I have control”. Two seconds later the autopilot was disconnected. There was no call out or conversation between the flight crew about autopilot disengagements. Based on the FDR data and the ATR72 autopilot disengagement logics analysis (see Appendix 14), the Safety Council concluded that the PF disconnected the autopilot when he had taken manual control of the aircraft.

Part 1.04.20 of the ATR72-600 FCOM indicated that when the autopilot was engaged, the pitch, roll and yaw actuators were connected to the flight controls, the pitch auto trim and yaw auto trim function were also activated. This meant that the ATR72-600 auto trim system automatically compensated for the yaw moment induced by an engine failure and back drove the rudder pedals in the cockpit.

As recorded in the FDR, after the autopilot was disengaged, the PF frequently applied trim control. In addition, the speed decreased due to the fact there were no more engine power and that the aircraft was maintained in a climb attitude. When the flight crew tried to follow the engine-out standard instrument departure (EOSID) after the master warning, the aircraft’s heading was set to 092 degrees by Captain B (PM), but the PF continually turned to the left after passing through a heading of 095 degrees. If the autopilot had not been disengaged at this point in the flight, the autopilot would have maintained heading 092 degrees and subsequently reduced the crew’s workload.

The PF’s decision to disconnect the autopilot shortly after the first master warning increased the PF’s subsequent workload and reduced his capacity to assess and cope with the emergency situation.

Non-Compliance with Procedures

TNA’s ATR72-600 SOP memory items for an engine number 2 flame out at take off (“ENG 2 FLAME OUT AT TAKE OFF”) required the PF to announce the failure, maintain aircraft control at all times and call for “engine flame out at take off memo items.” The PM shall confirm and callout that the ‘ATPCS UPTRIM’ and ‘AUTOFEATHER’ functions are activated and displayed on the EWD. Landing gear ‘UP’ and ‘BLEED 1 + 2’ were to be confirmed if no fault was present.The PF was then to adjust the aircraft’s attitude to accelerate to the aircraft’s target speed (VFTO).

However, the CVR transcript and FDR readout showed that the PF did not command “engine flame out at take off memo items”. The PM initiated the memory items and called out “engine flameout check” at 1053:00, which was approximately 22 seconds after the first master warning had annunciated. The PM then verified the activation of the ATPCS sequence and called “check up trim yes, auto feather yes” at 1053:02.

Instead of adjusting the aircraft’s attitude to accelerate to VFTO as per SOPs, the PF retarded power lever No. 1 (PL1) as indicated by a power lever angle (PLA) reduction from 66.5 to 49.2 degrees between 1053:05 and 1053:07. The aircraft continued to climb and airspeed subsequently decayed even though the PM alerted the PF about the airspeed and called out “okay now number two engine flameout confirmed”. The flight crew did not follow the ENG 2 flameout at take off procedures. The FDR readout showed that ENG 1 torque was reduced from 82.2% to 24.4% between 1053:05 and 1053:12. The power reduction on the operative engine resulted in the airspeed decaying until the stall warning systems, including audio alert, stick shaker, and stick pusher activated several times.

The engine flame out at take off procedures also required that, on completion of relevant memo items and after VFTO was acquired, the PF could then begin to shut down the affected engine when the flight path was stabilized. However, the CVR and FDR indicated that the stall warnings had activated before VFTO was acquired but the PF commanded the shutdown of ENG 1. That indicated that the PF skipped several required memory items and attempted to shut down ENG 1 when the flight path was not yet stabilized.

Part 03.02.03 of the ATR FCTM described the detailed crosscheck procedures and standard callouts for shutting down the affected engine. The following actions and callouts were required for shutting down an engine (example used is ENG 2):

  • When the flight crew decides to retard the affected side’s PL, the PF should point at the affected side’s PL and call “PL2?”. After being checked by the PM, followed by a response of “confirm”, the PF should then retard PL2 gently to the flight idle position and call “flight idle”; and then
  • When the flight crew decides to retard the affected side CL, the PM should point at it and call “CL2?”. After the PF checks and calls “confirm”, the PM should then retard CL2 to the feathered position and then to the fuel shut-off position and call out “feather, fuel shut-off”.

During the shutdown of ENG 1, the flight crew used non-standard processes and callouts in a noisy cockpit environment with frequent stall warnings. This deprived the crew of an opportunity to systematically assess and review the situation to ensure that both crewmembers understood that a loss of thrust had occurred on ENG 2.

The CVR and FDR showed that PL1 was further retarded to 34.5 degrees PLA at 1053:18 and CL1 was retarded to the shut off position at 1053:24. The resultant torque on ENG 1 reduced to 0% at 1053:27. The loss of all engine power combined with pitch attitude led the aircraft angle of attack to reach the stall warnings threshold. Ultimately the aircraft entered a stall from which the crew were unable to recover. The PF’s unannounced reductions in power on ENG 1 as a result his confusion regarding the identification and nature of the actual propulsion system malfunction led to the shut down and feathering of ENG 1 propeller. It appeared that the PM had not detected that the PF had once again manipulated PL1. The non-compliance with critical abnormal and emergency SOPs resulted in confusion in the cockpit and led to the operative engine being shut down. Had the crew followed the SOPs they would have increased the likelihood of jointly and correctly identifying the propulsion system malfunction and would have been in a position to restart that engine if there were no symptoms of damage. If the crew had nothing more than confirm the ENG 2 loss of thrust and returned to land using the remaining engine, the occurrence would not have occurred.

The GE222 investigation report had identified that flight crew non-compliance with SOPs was a systemic problem at TNA. Within 7 months of the GE222 accident, the GE235 accident occurred, and non-compliance with procedures were again identified not only during the occurrence flight but in interviews with company pilots.

A summary of non-compliance with SOPs and/or company expectations or non-conformance with safe practices identified during the occurrence flight included:

  • Non-compliance with sterile cockpit rule during taxi;
  • Did not brief engine out procedure during takeoff briefing;
  • Did not comply with the undocumented company expectation to reject the take off if the ATPCS did not arm during the takeoff roll (ATR72-600 only);
  • PF unnecessarily disconnected the autopilot after the master warning sounded;
  • PF did not positively identify propulsion system malfunction before taking action;
  • Crew did not perform the ENG 2 flameout at take off procedure

The non-compliance with procedures deprived the flight crew of an opportunity to manage the emergency correctly and efficiently. Their actions further complicated the situation, substantially increasing their workload, and a manageable situation eventuated in a stall and loss of aircraft control. The repetitive and recurring non-compliance with SOPs identified again in this occurrence and by previous ASC investigations of TransAsia Airways ATR accidents (GE222) and serious incidents, indicated that non-compliant behaviors were an enduring, systemic problem and were consistent with a poor safety culture within the airline’s ATR fleet. The recommended remedial measures by the airline and CAA were in progress or had not been implemented, and/or were not effective, and/or followed up by the time the GE235 accident had occurred.

Aircraft Recovery

The simulation testing indicated that the time required to restart ENG 1 was about 25 to 30 seconds after the restart procedure was initiated. However, the   stall warnings, including the stick pusher activated during the process with an altitude loss of up to 900 feet.

By the time the PF had realized he had shut down the wrong engine (ENG 1) and the crew attempted a restart, the aircraft was at an altitude of approximately 550 feet or 25 seconds to impact, which was insufficient for a successful restart and fly away. The aircraft stalled during the attempted restart at an altitude from which the aircraft could not recover.

During the simulation test (refer to 1.16.2), the investigation team found that the flight director bars provided a nose-up guidance contrary to the stick pusher nose-down inputs in stall test. Although the influence of the flight director indication was not demonstrated in the occurrence flight  and the logics of ATR flight director bars are consistent with other aircraft types within the industry, the flight director bars were in contradiction with the inputs to make in this situation and thus may disturb the crew. The Safety Council believes a review of the functional or display logic of the flight director is required at industry level so that it disappears or presents appropriate orders when a stall protection is automatically triggered.

Human Factors Perspectives of Flight Crew Performance

Flight Crew Performance

The flight crew could have identified the ENG 2 loss of thrust and maintained control of the aircraft if both crew members had shared a correct understanding and recognition of the propulsion system malfunction. The aircraft had significant performance and control margins and would have had no difficulty climbing clear of obstacles and returning to land on one engine. Furthermore, the SOPs permitted a restart attempt if the crew assessed that the inoperative ENG 2 was not damaged. In that instance, if power to ENG 2 had been restored, the crew would have had both engines operating and no difficulty returning to land.

The flight crew’s performance reflected many of the known findings in the “Propulsion System Malfunction + Inappropriate Crew Response (PSM+ICR)” report, U.S. Army study, and other human factors issues identified in the literature. In addition to non-compliance with SOPs, there were:

  • significant diagnostic discrepancies between crew members – PF did not recognize the propulsion system malfunction from the symptoms, cues, and/or indications with a resultant While the PM identified that ENG 2 had experienced a loss of thrust , he did not detect the subsequent shut down of ENG 1 by the PF, although the CVR indicated that the PM corrected the PF about retarding power lever during the initial stall warning sequence;
  • the PF did not assess the several sources of data that were available or utilize the PM effectively in the diagnostic process;
  • failures to properly control the aircraft after the initial propulsion system malfunction that should have been within their capabilities to handle;
  • areas for improvement in crew training which did not appear to address the malfunction characteristics (auditory and visual cues) most likely to result in inappropriate crew response;
  • an uncommanded power loss, which was the most common technical event;
  • PF shut down the wrong engine in response to an engine malfunction; and
  • the PF was too hasty in his response to the

Diagnostic Errors

The flight crew errors prevalent in the occurrence flight reflected the types of errors that occurred in other accidents and included errors in integrating and interpreting the data produced by propulsion system malfunctions were the most prevalent and varied in substance of all error types across events. The error data clearly indicated that additional training, both event specific and on system interactions, is required.

The PM initially appeared to comprehend that the propulsion system malfunction was related to ENG 2 but the PF did not have the same understanding of the situation. Rather, the PF became fixated on ENG 1 and did not respond to the indications on the EWD or the PM’s verbalizations regarding ENG 2. The observer did not appear to understand what was happening given that he was still under ATR-600 differences line training for the aircraft even though he was a very experienced pilot overall. All three crew members became confused by what was happening, particularly after both engines ceased operating as a result of the PF shutting down the operative ENG 1. The aircraft entered a stall during the ENG 1 restart attempt. The PF finally realized that he had “pulled back the wrong side throttle” at a point where the aircraft was unrecoverable.

Stress and Mental Preparation

In order to minimize the response times and ensure the most appropriate decisions in the event of an emergency, it was a company requirement and an industry practice that pilots conduct a pre-take off briefing. This briefing includes mentally reviewing the emergency procedures and deciding on the conditions of airspeed, height, rate of climb and/or aircraft configuration that must exist in order to continue the flight in the event of an engine failure. The pilots should endeavor to be mentally prepared to act, so that if an engine failure occurs at a critical stage of flight, an accurate assessment and response to the failure is implemented. Sudden and unexpected hazardous events are stressful for flight crews. If the flight crew is not able to cope with the stressors, it can lead to negative stress reactions, such as poor awareness, inaccurate decision making, reduced perception, illogical reasoning, low self control, and reduced vigilance. Abnormal and emergency SOPs are, in part, designed to provide a methodical means for handling stressful events, including an uncommanded autofeather after takeoff.

Captain A’s command upgrade and ATR72-600 differences training records within one year of the occurrence, contained several negative comments by IPs and/or CPs on his understanding and performance of single engine flameout at takeoff procedures. Even though Captain A finally passed the command upgrade and type differences training, there were indications that his ability to handle an engine failure at take off was marginal.

The CVR indicated that Captain A (PF) did not brief or review the engine failure procedure during the take off briefing or the company expectation that the take off should be rejected if the ATPCS failed to arm in the ATR72-600 during take off. The crew were not as mentally prepared as they could have been for the autofeather condition they had encountered in the absence of a pre-take off briefing. In addition, thorough system knowledge of the ATPCS may have indicated to the crew that its failure to arm earlier during the take off roll could be an indication of a more serious problem.

Captain A’s marginal ability to handle an engine failure at take off, under stress, and lack of mental preparation for the occurrence flight may have had a bearing on:

  • Captain A misidentifying ENG 1 as the malfunctioning engine even though Captain B announced ENG 2 flameout;
  • Captain A omitting several required items in the single engine flameout procedure and diverted his attention to ENG 1 throttle; and
  • Maintaining an appropriate airspeed not only for single engine operations but also above the stall with both engines inoperative. Captain A did not detect that airspeed was approaching the

Flight Crew Training and Competency Issues

After retiring from the military, Captain A had joined another local airline in September 2009 as a trainee first officer on the A330. His A330 initial transition training records indicated that he had difficulty on multi-tasking, prioritizing, making correct decisions, and performing under stress. After remedial training, his performance remained unsatisfactory and his training was discontinued in March 2010.

Captain A subsequently joined TNA in August 2010. He successfully completed initial ATR72-500 first officer training, and the subsequent recurrent proficiency training and checks. In April 2014, he met the criteria to be considered for command upgrade selection. His performance during the selection process was marginal. Captain A successfully completed his ground school and simulator sessions during the upgrade training but failed the final simulator check in May 2014. The unsatisfactory items were abnormal engine start, both hydraulic systems loss, and single engine approach go-around. The check airman’s comments indicated: incomplete procedure check and execution; and insufficient knowledge of emergency procedures.

After further training, Captain A passed the recheck in June 2014 and was promoted to Captain in July 2014. During his subsequent line training, certain instructors noted that because of his insufficient knowledge and confidence, he was hesitant in responding to “both EEC failure”, “engine failure after V1”and “smoke” emergencies during the oral test, and was prone to be nervous when conducting certain procedures or answering questions.

In October 2014, Captain A attended ATR72-500 to -600 differences training in Singapore. He was graded “may need extra training” after the simulator session with an instructor’s comment of “check engine-flame-out-at-take off callout and task sharing and go-around single engine” on 31 October 2014. This indicated that Captain A had completed the training but may need extra training in next training section or check to validate his handling an engine flame out at take off and single engine go-around. Captain A demonstrated above mentioned items again and passed the next section check on 2 November 2014.

Captain A’s command upgrade and ATR72-600 differences training records within one year of the occurrence, contained several negative comments by IPs and/or CPs on his understanding and performance of single engine flameout at take off procedures. Even though Captain A finally passed the command upgrade and type differences training, there were indications that his ability to handle an engine failure at the take-off was marginal.

Captain A’s performance during the occurrence was consistent with the reported difficulties  he  had  experienced  during  training, particularly when  performing in stressful emergency situations and included the following negative stress reactions: poor judgment; reduced perception; tendency to cut corners and skip items; and narrowed or restricted the focus of attention. However, TNA did not effectively address the evident and imminent flight safety risk that Captain A presented.

At the time of the occurrence, TNA pilots who performed unsatisfactorily during training or checking activities were offered remedial training for the specific failure items. However, no further review or follow-up occurred if the pilot’s performance was satisfactory on the subsequent check. As a result, TNA did not have a mechanism to identify those pilots who had a recurring pattern of critical performance deficiencies. If TNA had implemented an effective pilot performance review program, they may have been able to provide additional oversight of and/or remedial training for pilots whose performance was marginal. Additional references for air carriers to evaluate a flight crew’s ability under stressful situations may also be obtained from the CAA Civil Aviation Medical Center that provides relevant ability indexes (e.g., simultaneous capacity, stress tolerance) using an established assessment system. In cases where pilots were still unable to consistently meet the required standards and, in accordance with common airline industry practice, the pilots flying duties should have been discontinued.

Command Upgrade Process

Captain A was promoted to captain in 2014 together with three other first officers. A review of their upgrade process and training identified that:

  • In accordance with the flight operations manual, TNA’s upgrade selection panel should have comprised at least eight IPs/CPs at the time to assess the candidates initial oral test performance. However, when the Captain A attempted the upgrade selection, the selection panel assessing the Captain’s oral test performance comprised only six ATR72 IPs/CPs.
  • Three of the upgrade candidates, including Captain A, attended and passed the upgrade ground test on 12 May 2014 before they had completed all the required ground courses. That was not in compliance with the training rules in the TNA

The airline did not follow its own procedures when selecting and training Captain A for an upgrade. TNA’s quality assurance processes had not detected that the command selection upgrade process had been compromised.

Crew Resource Management and Crew Coordination

During the occurrence flight, several CRM and crew coordination problems were observed throughout the occurrence flight.

Sterile cockpit environment

According to the CVR from 1041 to 1051, with the exception of performing pre-departure procedures, Captain A (PF) had few additional interactions with Captain B (PM) or the observer pilot. However, Captain B and the observer pilot had a significant number of technical discussions and demonstrations of aircraft systems during the aircraft’s push back, propeller rotation, taxi, and holding for takeoff. This was not in accordance with the sterile cockpit rule for that phase of flight. Even though the intention of those discussions was to educate the observer pilot about the aircraft’s systems as part of his familiarization training, those lengthy discussions were a source of distraction and may have impeded communication and team building with Captain A. Those discussions may have resulted in the omission of an appropriate pre-take off briefing.

Crew communication

Both crew members failed to obtain relevant data from each other regarding the status of both engines at different points in the occurrence sequence. The failure by the PF to integrate input from the PM highlighted the fact that inputs to the process of developing a complete picture of relevant cues for understanding what was happening and where can and often must come from other crew members as well as from an individual’s cue-seeking activity.

The quality of the crew’s performance depended largely on their ability to recognize the ENG 2 loss of thrust and to respond to the situation by functioning effectively as a team. The training the crew had completed, while meeting regulatory requirements, was not best practice for a complex, twin-engine turboprop aircraft such as the ATR72-600.

During the occurrence flight, several ineffective communication practices were identified:

  • After the uncommanded ENG 2 auto-feathering and between 1052:43 and 1053:07, it appeared that Captain B (PM) asked Captain A (PF) to wait or delay his movement of the power lever 1 (PL1) until the cross check was completed. While the PF momentarily delayed any further retardation of PL1, he later continued  to  reduce power  on  ENG  1  which  was  probably not detected by the PM until the stall warnings and stick shaker activated just before the PF shut down the wrong engine without the required crosschecks. The CVR indicated that the PM attempted to instruct the PF to push the throttle back up but the PF continued to shut down ENG 1. The PM did not appear to challenge the PF about his actions;
  • At 1053:05, the PM observed the decreasing airspeed and reminded the PF to “watch the speed”. However, the PF did not increase airspeed in response. The PM did not challenge the PF again in response to his inaction regarding the reducing airspeed;
  • At 1053:07, the PM announced: “number two engine flameout confirmed”. Even though the PF responded “okay”, he did not process the information because it was apparent that he still believed the affected engine was ENG The PF did not announce or confirm his belief that number one engine had flamed out. If the PF had used clear feedback as per SOPs, and announced his belief that ENG 1 was the inoperative engine, it would have provided the PM an opportunity to address the PF’s misdiagnosis;
  • ENG 1 was shut down by the flight crew from 1053:15 to 1053:25. However, flight crew’s callouts were nonstandard and unclear during the engine shutdown crosscheck

Failure to utilize available resources

Unless the emergency procedures directed the crew to disconnect the autopilot, it was recommended that it be used as much as possible during these types of situations. However, the PF disconnected the autopilot after the uncommanded auto-feather, which increased his workload. In addition, the ATR72-600 aircraft was equipped with an engine and warning display (EWD) system, which clearly indicated that the propulsion system malfunction was an inoperative ENG 2 (‘ENG 2 OUT’). However, the PF did not appear to process the information on the EWD.

Ineffective leadership

When the availability, competency, quality or timeliness of leadership does not meet task demands an unsafe situation can arise101. Captain A (PF), as the designated pilot-in-command (PIC), was responsible for supervising the overall management of the flight. However, after the uncommanded ENG 2 auto-feather, the PF was unable to stabilize and configure the aircraft correctly for single engine operations. He also did not share his understanding of the situation and respond in accordance with SOPs, which provided clear task management  roles  for  each pilot. The absence of leadership, in part, contributed to the confusion in the cockpit and the failure to follow SOPs. However, Captain B (PM) as an experienced pilot did not intervene or take-over to mitigate the absence of leadership from the PF.

TNA Crew Resource Management Training

Effective crew resource management (CRM) begins in initial training and is reinforced by recurrent practice, assessment, and feedback, and should be embedded in every stage of a pilot’s training.

The Taiwan CAA issued an Advisory Circular 120-005B on CRM on 23 June 2004. The AC comprised guidance material to help airlines develop, implement, reinforce, and assess CRM training programs. In addition, there were several sets of widely available aviation CRM guidelines. With reference to that material, and as previously identified in the GE222 investigation, there were several deficiencies in TNA’s CRM training:

  • TNA had not established a systematic CRM assessment process to determine if their training was effective and achieving its goals. This may have resulted in critical areas requiring reinforcement during recurrent training not being identified and/or continuous improvements not being made;
  • Proficiency, competency and confidence in CRM instruction, observation, and measurement require specialist training for CRM facilitators, supervisors, IPs, and CPs. However, TNA did not provide adequate CRM instructor training so the instructors could teach and evaluate a candidate’s practical CRM skills;
  • The practical application and demonstration of CRM skills during simulator training depended largely on the experience of individual IP’s had differing views. TNA had not implemented a formal process for developing detailed and standardized line-oriented flight training (LOFT) training with specific CRM objectives;
  • Audiovisual feedback during LOFT and simulator debriefings was generally not utilized by TNA IPs. Such a tool can be very effective in assisting crews to evaluate and improve their own CRM performance; Unlike some other airlines, TNA’s command upgrade training did not include a human factors Operational Simulations: Line-Oriented Flight Training, Special Purpose Operational Training, Line Operational Evaluation, etc. (HF) course, with elements addressing some of the HF challenges associated with command;
  • The CRM ground course training materials were very limited and did not reflect current CRM research and industry best practice in regards to communication/ interpersonal skills, problem-solving/decision-making, leadership/followership, and critique, and so on. In addition, there was no documented recurrent CRM course syllabus, learning objectives, or length/training hour

TNA did not use widely available CRM guidelines to develop, implement, reinforce, and assess their flight crew CRM training program. The occurrence flight crew’s performance was consistent with ineffective CRM training. Finally, as identified in the GE222 investigation, the CAA’s oversight of flight crew training, including CRM training, was in need of significant improvement.

Negative Transfer

An understanding of why the PF shut down the ENG 1 (the ‘wrong engine’), which was fully operative was explored. Hypotheses regarding the potential influence of the pilot’s previous multi-engine training and experience were considered. Interviews with TNA ATR72 flight crew indicated that the ENG 1 was not constantly used as the reference engine for simulated engine failure training and checking scenarios. However, Captain A had experienced one previous  uncommanded auto-feather event involving the ENG 1 during a normal revenue flight when he was a TNA first officer acting in the role of PM. The likelihood that negative transfer adversely affected the PF’s response to the uncommanded ENG 2 auto-feather was unable to be established.

ATR72 Differences Training Program and TNA Records Management

Training Program

TNA’s ATR72-500 to ATR72-600 differences training program was developed in accordance with the European Aviation Safety Agency (EASA) ATR42/72 Flight Crew Qualifications Operational Evaluation Board (OEB) report. There were various types of ATR72-600 differences training programs depending on the pilot’s total flight time, type experience, and the configuration and onboard equipment of previous ATR72 aircraft flown. The two standard ATR72-600 differences training programs recommended by the OEB report included 5-day and 10-day programs. The TNA ATR72-600 differences training program approved by the CAA followed the 5-day program defined in the OEB report. The differences training records also showed that, at the commencement of training, the ATR instructors checked every TNA pilot’s qualifications to ensure that they met the pre-requisites for the 5-day training program. In addition to the ATR training, the CAA required that an  extra simulator check to be conducted by a designated examiner (DE) or CAA inspector following the ATR ground and simulator training.

The TNA ATR72-600 differences training program was compliant from a CAA regulatory perspective. However, interviews with TNA ATR72-600 pilots indicated that pilots without advanced automation experience found the differences training to be inadequate, especially in regard to FMS and electronic displays familiarization. With reference to the GE235 occurrence, the CVR and FDR showed that Captain A (PF) failed to utilize the autopilot and flight warning system to identify and manage the emergency situation. This may have been a result of Captain A’s lack of knowledge, understanding, and confidence in using the aircraft’s automated support systems, which may, in part, have been a function of insufficient differences training. Captain A’s simulator check at the conclusion of differences training indicated that he may need further training particularly for engine out operations. The CAA and TNA need to reconsider if the current 5-day ATR72 differences course and subsequent line training is sufficient to ensure that TNA flight crews are competent to operate the ATR72-600 under all normal and non-normal conditions.

Furthermore, the flight instrument differences of ATR72-500 and ATR72-600 is from conventional flight instruments, including analog displays, to a more advanced avionic suite with PFD and electronic checklist. The visual pattern and information picked up by the crew in an emergency situation may not be retrieved at the same location with the same display, although in the GE235occurrence the CVR evidenced that the PM called-out the proper engine flame out procedure associated with ENG 2 and that the PF was still mentioning the ENG 1. The Safety Council believes it is required to study the content and the duration of the minimum requirement regarding a difference course between a conventional avionics cockpit and an advanced suite including enhanced automated modes for aircraft having the same type rating.

Records Management

According to the aircraft flight operation regulations and TNA’s flight operations manual, TNA was required to establish a system to retain all flight crew training records during the employment period for CAA’s inspection.

However, TNA flight crew training records showed that the ART72-600 differences training records for all ATR72-600 pilots were not completely maintained by TNA. The TNA training department assistant manager advised that the differences training records were kept at ATR training center in Singapore.

TNA failed to maintain the differences training records in accordance with the Aircraft Flight Operation Regulations and the TNA flight operations manual.

The ATR72-600 differences training records for the GE235 flight crew showed that Captain A may need more training on the single engine flameout at take off procedure. That meant if the differences training records were stored, adequately maintained and evaluated by appropriate TNA flight operations and/or quality assurance personnel, TNA would have had yet another opportunity to review Captain A’s ability to handle engine-out emergencies.

CAA Oversight

After the GE222 occurrence, the CAA conducted an in-depth inspection of TNA flight operations, system operations control, and safety and security from 14 to 30 August 2014. In response to that CAA inspection, TNA initiated several programs to improve flight safety. Those programs included addressing the deficiencies in the airline’s safety management system (SMS) and flight operations quality assurance (FOQA) system, the standardization of flight crew training and checking, the establishment of procedures for continuous descent final approach (CDFA), and the improvement of crew resource management (CRM) training and flight crew fatigue management.

These safety issues were still being addressed by the airline at the time of the GE235 occurrence, which was seven months after the GE222 occurrence. The systemic TNA flight crew non-compliance with procedures remained unaddressed. The CAA urgently needs to enhance the surveillance of TNA’s operations and ensure that TNA’s safety improvement programs implemented in a timely and effective manner. The GE222 investigation was still in progress when the Council initiated the GE235 investigation. During the GE222 investigation, the Council identified specific CAA regulatory oversight issues. The GE222 and GE235 investigation revealed that there were similar problems with CAA oversight of TNA. The GE222 investigation report has already documented the specific areas for improvement in CAA’s regulatory surveillance activities so they were not discussed further in this report.

Findings as the result of this investigation

The ASC presents the findings derived from the factual information gathered during the investigation and the analysis of the occurrence. The findings are presented in three categories: findings related to probable causes, findings related to risk, and other findings.

The findings related to probable causes identify elements that have been shown to have operated in the occurrence, or almost certainly operated in the occurrence. These findings are associated with unsafe acts, unsafe conditions, or safety deficiencies associated with safety significant events that played a major role in the circumstances leading to the occurrence.

The findings related to risk identify elements of risk that have the potential to degrade aviation safety. Some of the findings in this category identify unsafe acts, unsafe conditions, and safety deficiencies including organizational and systemic risks, that made this occurrence more likely; however, they cannot be clearly shown to have operated in the occurrence alone. Furthermore, some of the findings in this category identify risks that are unlikely to be related to the occurrence but, nonetheless, were safety deficiencies that may warrant future safety actions.

Other findings identify elements that have the potential to enhance aviation safety, resolve a controversial issue, or clarify an ambiguity point which remains to be resolved. Some of these findings are of general interests that are often included in the ICAO format accident reports for informational, safety awareness, education, and improvement purposes.

Findings Related to Probable Causes

Powerplant

  1. An intermittent signal discontinuity between the auto-feather unit (AFU) number 2 and the torque sensor may have caused the automatic take off power control system (ATPCS):
  • Not being armed steadily during takeoff roll;
  • Being activated during initial climb which resulted in a complete ATPCS sequence including the engine number 2 auto-feathering.
  1. The available evidence indicated the intermittent discontinuity between torque sensor and auto feather unit (AFU) number 2 was probably caused by the compromised soldering joints inside the AFU number 2.

Flight Operations

  1. The flight crew did not reject the take off when the automatic take off power control system ARM pushbutton did not light during the initial stages of the takeoff roll.
  2. TransAsia Airways did not have a clear documented company policy with associated instructions, procedures, and notices to crew for ATR72-600 operations communicating the requirement to reject the take off if the automatic take off power control system did not arm.
  3. Following the uncommanded auto-feather of engine number 2, the flight crew failed to perform the documented failure identification procedure before executing any actions. That resulted in pilot flying’s confusion regarding the identification and nature of the actual propulsion system malfunction and he reduced power on the operative engine number 1.
  4. The flight crew’s non-compliance with TransAsia Airways ATR72-600 standard operating procedures – Abnormal and Emergency Procedures for an engine flame out at take off resulted in the pilot flying reducing power on and then shutting down the wrong engine.
  5. The loss of engine power during the initial climb and inappropriate flight control inputs by the pilot flying generated a series of stall warnings, including activation of the stick pusher. The crew did not respond to the stall warnings in a timely and effective manner.
  6. The loss of power from both engines was not detected and corrected by the crew in time to restart an engine. The aircraft stalled during the attempted restart at an altitude from which the aircraft could not recover from the loss of control.
  7. Flight crew coordination, communication, and threat and error management (TEM) were less than effective and compromised the safety of the flight. Both operating crew members failed to obtain relevant data from each other regarding the status of both engines at different points in the occurrence sequence. The pilot flying did not appropriately respond to or integrate input from the pilot monitoring.

Findings Related to Risk

Powerplant

  1. The engine manufacturer attempted to control intermittent continuity failures of the auto-feather unit (AFU) by introducing a recommended inspection service bulletin at 12,000 flight hours to address aging issues. The two AFU failures at 1,624 flight hours and 1,206 flight hours show that causes of intermittent continuity failures of the AFU were not only related to aging but also to other previously undiscovered issues    and    that    the   inspection    service bulletin  implemented by the engine manufacturer to address this issue before the occurrence was not sufficiently effective. The engine manufacturer has issued a modification addressing the specific finding of this investigation. This new modification is currently implemented in all new production engines, and another service bulletin is available for retrofit.

Flight Operations

  1. Pilot flying’s decision to disconnect the autopilot shortly after the first master warning increased the pilot flying’s subsequent workload and reduced his capacity to assess and cope with the emergency situation.
  2. The omission of the required pre-take off briefing meant that the crew was not as mentally prepared as they could have been for the propulsion system malfunction they encountered after takeoff.

Airline Safety Management

  1. TransAsia Airways (TNA) did not follow its own procedures when selecting and training pilot flying for an upgrade. The TNA’s quality assurance processes had not detected that the command selection upgrade process had been compromised.
  2. TransAsia Airways (TNA) did not use widely available crew resource management (CRM) guidelines to develop, implement, reinforce, and assess the effectiveness of their flight crew CRM training program.
  3. While the TransAsia Airways (TNA) ATR72-600 differences training program was consistent and compliant with the European Aviation Safety Agency ATR72 operational evaluation board report from a Civil Aeronautics Administration regulatory perspective, it may not have been sufficient to ensure that TNA flight crews were competent to operate the ATR72-600 under all normal procedures and a set of abnormal conditions.
  4. The ATR72-600 differences training records for the GE 235 flight crew showed that Captain A probably needed more training on the single engine flame-out at take off procedure. That meant if the differences training records were stored, adequately maintained and evaluated by appropriate TransAsia Airways (TNA) flight operations and/or quality assurance personnel, the TNA would have had yet another opportunity to review Captain A’s ability to handle engine-out emergencies.
  5. Captain A’s performance during the occurrence was consistent with his performance weaknesses noted during his training, including his continued difficulties in handling emergency and/or abnormal situations, including engine flame out at take off and single engine operations. However, TransAsia Airways did not effectively address the evident and imminent flight safety risk that Captain A presented.

Regulatory Oversight

  1. The Civil Aeronautics Administration’s (CAA) oversight of flight crew training, including crew resource management (CRM) training, is in need of improvement.
  2. The systemic TransAsia Airways (TNA) flight crew non-compliances with standard operating procedures identified in previous investigations, including GE 222, remained unaddressed at the time of the GE235 occurrence. Although the Civil Aeronautics Administration (CAA) had conducted a special audit after the GE 222 accident which identified the standard operating procedures compliance issue, the CAA did not ensure that TNA responded to previously identified systemic safety issues in a timely manner to minimize the potential risk.

Other Findings

  1. The flight crew was certificated and qualified in accordance with Civil Aeronautics Administration (CAA) regulations and company requirements. There was no evidence to indicate that the flight crew’s performance might have been adversely affected by pre-existing medical conditions, fatigue, medication, other drugs or alcohol during the occurrence flight.
  2. Visual meteorological conditions (VMC) prevailed at the time of the aircraft’s departure. No adverse weather conditions were present for the flight.
  3. The aircraft’s certificate of airworthiness and registration were current at the time of the occurrence. The occurrence aircraft was dispatched at Songshan Airport with no known defects and was in compliance with all applicable airworthiness directives and service bulletins. A review of the aircraft’s maintenance records before the occurrence flight revealed that there were no defects reported that related to engine number 2 automatic feathering system.
  4. Flight crew transferred from conventional flight instruments to a more advanced avionic suite with primary flight display, the visual pattern and information picked up by the crew in an emergency situation may not be retrieved at the same location with the same display.
  5. Although the influence of the flight director indication was not demonstrated in the occurrence flight and the logics of ATR flight director bars are consistent with other aircraft types within the industry, the simulator flight illustrated the flight director bars indication during stall warning were in contradiction with the automatic stall protection inputs and thus may disturb the crew.
  6. The ATR72 formal document has no general statement of rejecting take off policy and procedure of rejecting take off with both engines operative.

Safety Recommendations To TransAsia Airways

  1. Document a clear company policy with associated instructions, procedures, training, and notices to crew members for ATR72-600 operations communicating the requirement to reject a takeoff in the event that the automatic take off power control system (ATPCS) is not armed as required. (ASC-ASR-16-06-001)
  2. Conduct a thorough review of the airline’s flight crew training programs, including recurrent training, crew resource management (CRM) training, upgrade training, differences training, and devise systematic measures to ensure that
  • Standardized flight crew check and training are conducted;
  • All flight crews comply with standard operating procedures;
  • All flight crews are proficient in handling abnormal and emergency procedures, including engine flame out at takeoff;
  • The airlines use widely available guidelines to develop, implement, reinforce, and assess the effectiveness of their flight crew resource management (CRM) training program, particularly the practical application of those skills in handling emergencies;
  • Command upgrade process and training comply with the airline’s procedures and that competent candidates are selected;
  • ATR72-600 differences training and subsequent line training are sufficient to ensure that flight crews are competent to operate the ATR72-600 under all normal and abnormal conditions; and
  • All flight crew training records during the employment period are retained in compliance with the aircraft flight operation regulations.

(ASC-ASR-16-06-002)

  1. Improve the airline’s internal quality assurance oversight and audit processes to ensure that recurring safety, training and administrative problems are identified and rectified in a timely manner. (ASC-ASR-16-06-003)
  2. Implement and document an effective and formal pilot performance review program to identify and manage pilots whose performance is marginal. (ASC-ASR-16-06-004)
  3. Evaluate the safety culture of the airline to develop an understanding of the reasons for the airline’s unacceptable safety performance, especially the recurring noncompliance with procedures. (ASC-ASR-16-06-005)

To Civil Aeronautics Administration

  1. Review airline safety oversight measures to ensure that safety deficiencies are identified and addressed in an effective and timely manner. (ASC-ASR-16-06-006)
  2. Implement a highly robust regulatory oversight process to ensure that airline safety improvements, in response to investigations, audits, or inspections, are implemented in a timely and effective manner. (ASC-ASR-16-06-007)
  3. Conduct a detailed review of the regulatory oversight of TransAsia Airways to identify and ensure that the known operational safety deficiencies, including crew noncompliance with procedures, nonstandard training practices, and unsatisfactory safety management, were addressed effectively. (ASC-ASR-16-06-008)
  4. Provide inspectors with detailed guidance on how to evaluate the effectiveness of operator nontechnical training programs such as crew resource management (CRM) and threat and error management (TEM) training programs. (ASC-ASR-16-06-009)

 To UTC Aerospace System Company

  1. Work with the manufacturers of engine and aircraft to assess the current operating parameters and aircraft risks associated with the PW127 series engine auto feather unit (AFU) to minimize or  prevent occurrences that could result in uncommanded  auto-feather. (ASC-ASR-16-06-010)

To Pratt & Whitney Canada

  1. Work with manufacturers of the auto-feather unit (AFU) and aircraft to assess the current operating parameters and aircraft risks associated with the PW127 series engine auto feather unit to minimize or prevent occurrences that could result in uncommanded auto-feather. (ASC-ASR-16-06-011)

To Avions de Transport Régional

  1. Work with manufacturers of the auto-feather unit and engine to assess the current operating parameters and aircraft risks associated with the PW127 series engine auto feather unit (AFU) to minimize or prevent occurrences that could result in uncommanded auto-feather. (ASC-ASR-16-06-012)
  2. Publish in the flight crew operating manual (FCOM) an operational procedure related to rejected take off and expanded information regarding conditions leading to rejected take off. (ASC-ASR-16-06-013)

To European Aviation Safety Agency

  1. Require a review at industry level of manufacturer’s functional or display logic of the flight director so that it disappears or presents appropriate orders when a stall protection is automatically triggered. (ASC-ASR-16-06-014)
  2. Study the content and the duration of the minimum requirement regarding a differences training program between a conventional avionics cockpit and an advanced suite including enhanced automated modes for aircraft having the same type rating. (ASC-ASR-16-06-015)
  3. Require a review of manufacturer’s airplane flight manual (AFM) to ensure that a rejected take off procedure is also applicable to both engines operating. (ASC-ASR-16-06-016)

Excerpted from Aviation Safety Council Taipei-Taiwan Aviation Occurrence Report, 4 February 2015 TransAsia Airways Flight GE235, ATR72-212A, Loss of Control and Crashed into Keelung River Three Nautical Miles East of Songshan Airport. Report Number: ASC-AOR-16-06-001Date: June 2016. English report released on July 1st, 2016.

Further reading The Organizational Influences behind the aviation accidents

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Human Factors in Aviation

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