Eastern Air Lines Runway Excursion at La Guardia, final report

Several failures in close succession by a jetliner’s flight crew were the probable cause of Oct. 27, 2016, runway excursion at La Guardia Airport, according to the National Transportation Safety Board’s final report issued September 21, 2017. Some recurrent training issues were identified as contributing factors.


Photo (C) ABC news


History of Flight

Landing-flare/touchdown:  Landing area overshoot

Landing-landing roll:  Runway excursion (Defining event)

On October 27, 2016, about 1942 eastern daylight time, Eastern Air Lines flight 3452, a Boeing 737-700, N923CL, overran runway 22 during the landing roll at LaGuardia Airport (KLGA), Flushing, Queens, New York. The airplane travelled through the right forward corner of the engineered materials arresting system (EMAS) at the departure end of the runway and came to rest off the right side of the EMAS. The 2 certificated airline transport pilots, 7 cabin crewmembers, and 39 passengers were not injured and evacuated the airplane via airstairs.

The airplane sustained minor damage. The charter flight was operating under the provisions of 14 Code of Federal Regulations Part 121. Night instrument flight rules conditions prevailed at the airport at the time of the incident, and an instrument flight rules flight plan was filed for the flight, which originated at Fort Dodge Regional Airport (KFOD), Fort Dodge, Iowa, about 1623 central daylight time.

The first leg of the trip began on October 14, 2016, and the captain and first officer were paired from then to the incident. In post-incident statements, the flight crew indicated that the captain was the pilot monitoring (PM) for the incident flight, and the first officer was the pilot flying (PF). The first officer reported that the autopilot and autothrottles were engaged beginning about 2,500 ft after their takeoff from KFOD. Both pilots stated that the en route portion of the flight and the descent into the terminal area were uneventful but they encountered moderate to heavy rain during the final 15 minutes of the flight.

According to information from the airplane’s cockpit voice recorder (CVR), the first officer partially briefed the instrument landing system (ILS) approach for runway 13 beginning about 1848, indicating an autobrake setting of 3 and a 30º flap setting. ATIS information “Bravo” was current at that time and indicated visibility 3 miles in rain, ceiling 1,500 ft broken, overcast at 2,200 ft, wind from 130º at 9 knots, and that braking action advisories were in effect. About 1852, the first officer began briefing the ILS approach for runway 22 after the captain clarified, based on the ATIS recording, that runway 13 was being used for departures.

About 1902, as the airplane descended through 18,000 ft msl, the flight crew completed the approach briefing for runway 22, with the same autobrake and flap setting as indicated earlier, as well as the decision altitude and visibility required for the approach, the touchdown zone elevation, and a reference speed (Vref) of 137 knots. ATIS information “Charlie” was current at that time and indicated visibility 3 miles in rain, ceiling 900 ft broken, overcast at 1,500 ft, and wind from 120º at 9 knots.

The flight crew also discussed the captain manually deploying the speed brakes (the airplane’s automatic speed brake module had been deactivated 2 days before the incident and deferred in accordance with the company’s minimum equipment list (MEL), with corrective action scheduled for November 4, 2016). In reference to the manual deployment of the speed brakes, the captain stated at 1902:44.5 “you’re gonna do these. I’m gonna do this” to which the first officer replied “[that] is correct.”

About 1927, the flight was provided vectors to the final approach course for the ILS approach to runway 22. About 1936, the flight was cleared for the approach. The first officer then called for the landing gear to be extended and the flaps set at 15º. About 1937, the captain stated that the localizer and glideslope were captured. About 1938, as the airplane neared the final approach fix, the flight crew completed the landing checklist and configured the airplane for landing, with flaps set to 30º.

The CVR indicates that the captain pointed out the approach lights about 1939. The first officer reported, and flight data recorder (FDR) data indicate, that about 1940:12, he disconnected the autopilot when the airplane’s altitude was about 300 ft radio altitude, as required by Eastern Air Lines standard operating procedure. FDR data indicate that the first officer disconnected the autothrottles about 1940:19.

FDR data indicate that, shortly after the first officer disconnected the autopilot and autothrottles (about 300 ft radio altitude), the airplane began to increasingly deviate above the glideslope beam and crossed the threshold at a height consistent with the threshold crossing height of the VGSI, which was not coincident with the glide slope beam. CVR data indicate that between 1940:35 and 1940:46, the enhanced ground proximity warning system alerted the decreasing altitude in increments of 10, beginning at 50 ft. The pitch attitude started to increase in the flare from 2.8° at a radio altitude of about 38 ft. After the 20-ft alert, the captain stated “down” at 1940:43.3. After the 10-ft alert, the captain stated, “down down down down you’re three thousand feet remaining” at 1940:46.6. There was no callout of spoilers or thrust reversers during the rollout on the CVR.

FDR data and performance calculations indicate that the airplane crossed the runway threshold at a radio altitude of 66 ft, with an increasing glideslope deviation and a descent rate of about 750 ft per minute. When the airplane had travelled about 2,500 ft beyond the runway threshold, its descent rate decreased to near zero, and it floated before touching down. The captain later reported that the descent to the touchdown zone was normal until the flare. He stated that the airplane floated initially in the flare, which prompted the captain to tell the first officer to “get it down.”

The first officer recalled hearing the captain’s instruction to “put [the airplane] down” during the flare but was not certain how far down the runway the airplane touched down. FDR data indicate that at 1940:51.8, the airplane’s main landing gear touched down; maximum manual wheel brakes were applied at main gear touchdown. The throttles were not fully reduced to idle until about 16 seconds after the flare was initiated, and after the airplane had touched down.

The touchdown point was about 4,242 ft beyond the threshold of the 7,001-ft-long runway. The nose gear initially touched down about 2 seconds after the main landing gear but rebounded into the air due to aft control column input. The nose gear touched down a second and final time at 1940:56.8.

The captain reported that, as briefed, he manually deployed the speed brakes, which FDR data indicate were manually extended to full at 1940:56.3, about 4.5 seconds after the main landing gear touched down and the airplane had travelled about 1,250 ft farther down the runway from the touchdown point. At 1940:59.8, when the airplane had travelled about 1,650 ft down the runway from the touchdown point (and 5,892 ft from the threshold), maximum reverse thrust was commanded. The captain reported that he saw the end of the runway approaching and began to apply maximum braking, as well as right rudder because he thought it would be better to veer to the right rather than continue straight to the road beyond the end of the runway.

The first officer reported that the captain did not, as required in the operator’s procedures, tell him that he was attempting to brake and steer the airplane during the landing rollout, and no such callout is recorded on the CVR. The first officer stated that the airplane was pulling to the right “really hard,” which prompted him to apply left rudder. He reported that the left rudder input was counter to his expectation due to a 9-knot crosswind from the left, which he expected to counteract with right rudder input. He attempted to maintain alignment with the runway centerline by applying left rudder and overriding the autobrakes with pressure on the brake pedal.

At 1941:08.3, the CVR recorded the sound of rumbling, consistent with the airplane exiting the runway. The airplane then entered the EMAS about 35 knots groundspeed and came to rest 172 ft beyond the end of the runway and to the right of the EMAS. Review of the CVR recording revealed that, after the airplane came to a stop, the first officer twice remarked that they should have conducted a go-around, and the captain agreed. The first officer later reported that he did not believe the approach or landing were abnormal at the time. The captain later stated that he should have called for a go-around when the airplane floated during the flare.


Photo (C) REUTERS Lucas Jackson

Flight Crew Information

Pilot 1

Pilot 2

Meteorological Information and Flight Plan


At 1851 EDT, (ASOS) at KLGA reported the wind from 090° true at 9 knots, visibility of 3 statute miles (sm), moderate rain, ceiling broken at 900 ft agl, overcast clouds at 1,500 ft agl, temperature of 13°C and a dew point temperature of 11°C, and altimeter setting of 30.14 inches of mercury. Remarks included: surface visibility of 4 sm, precipitation accumulation of 0.14 inch since 1751 EDT.

At 1951 EDT, KLGA ASOS reported the wind from 100° true at 10 knots with gusts to 15 knots, visibility of 3 sm, moderate rain, mist, ceiling overcast at 1,000 ft agl, temperature of 13°C and a dew point temperature of 12°C, and an altimeter setting of 30.10 inches of mercury. Remarks included: surface visibility of 4 sm, precipitation accumulation of 0.32 inch since 1851 EDT, precipitation accumulation of 0.61 inch during previous 3 hours.

Wreckage and Impact Information

Crew:  11 Injuries: None

Passenger: 37 Injuries: None

Ground Injuries: N/A

Total 48 Injuries: None

Aircraft Damage: Minor

Aircraft Fire: None

Aircraft Explosion: None

Latitude, Longitude: 40.769167, -73.885000

As a result of the airplane’s travel through the EMAS, pulverized EMAS material (a gray, powdery residue) was noted on portions of the airplane’s exterior during postincident examination. The lower and forward portions of the airplane—fuselage, landing gear, and antennas—were coated with a dried residue resulting from the mixture of the EMAS material and rainwater. In addition, pieces of a matting material used in the EMAS were found in various locations on the airplane.

No damage or anomalies were noted during the visual examination of the nosewheel landing gear and associated assemblies. A preliminary visual examination of the main landing gear strut, doors, assemblies, associated hydraulic lines, and antiskid components did not reveal evidence of physical damage. However, after the airplane was cleaned of EMAS debris and the main landing gears were retracted, damage was noted on the underside of each gear strut. The operator indicated that the lower wire bundle support brackets for the left and right main landing gear were both damaged, as well as the wire conduit sleeve on the left main landing gear.

Each of the four main wheel tires showed cut damage in addition to normal wear. None of the observed cuts were deep enough to reach the tire treads. No flat spots or other evidence of hydroplaning was noted on any of the tires. Examination of the four brake assemblies found no evidence of damage or hydraulic leaks. No evidence of a hydraulic power malfunction or damage to any of the visible hydraulic lines was noted.

Both engines showed evidence of EMAS material and matting on the engine inlet and internal components. The No. 1 engine sustained fan blade damage, including four blades bent in the direction opposite of rotation, at the tip corner. No visible blade damage was noted on the No. 2 engine. Visual examination of the thrust reversers found no preincident anomalies. The operator later reported that, after cleaning and deploying the thrust reversers, damage was found on the inboard thrust reverser sleeves and blocker doors for both engines.


Photo (C) NTSB

Examination of the speed brake control components on the incident airplane noted the speed brake handle positioned full forward. All spoiler panels, including the ground spoilers, were found in the down or retracted position. No damage was noted to any of the ground spoilers.


No problems with communications equipment were reported.

Flight Recorders

The airplane was equipped with a cockpit voice recorder (CVR) and a flight data recorder (FDR). Both recorders were removed from the airplane and retained by the NTSB for further examination and readout at the NTSB’s Recorder Laboratory in Washington, DC. The recorders showed no signs of damage.

Cockpit Voice Recorder

The CVR, a Honeywell 6022, serial number 3452, was a solid-state CVR that recorded 120 minutes of digital audio. It was played back normally without difficulty and contained excellent quality audio information. The recording was transcribed in two parts focusing on the en route approach briefing and the approach, landing, and events thereafter until the end of the recording. Part one began at 18:48:06 EDT, when flight 3452 was en route at FL390, and continued until 1902:52 EDT. Part two began at 1918:01 EDT and ended at 1948:32 EDT (the end of the recording

Flight Data Recorder

The FDR, a Honeywell 4700, serial number SSFDR-16936, recorded airplane flight information in digital format using solid-state flash memory as the recording medium. The FDR could record a minimum of 25 hours of flight data and was configured to record 256 12-bit words of digital information every second. The FDR was designed to meet the crash survivability requirements of Technical Standard Order C-124.

Data from the FDR were extracted normally. The event flight was the last flight of the recording, and its duration was about 2 hours and 19 minutes.

Medical And Pathological Information

Eastern Air Lines conducted drug and alcohol testing for both pilots about 6 hours after the incident. Test results were negative for alcohol and major drugs of abuse.

Organizational And Management Information

Company Overview and Management Organization

Eastern Air Lines, Inc., received certification to operate as a Part 121 supplemental carrier on May 15, 2015. Subsequently, Eastern Air Lines began scheduled charter services to Havana and four other cities in Cuba. Before the incident, the airline also launched charter service to other Latin American and Caribbean destinations. The airline’s sole base of operations was at Miami International Airport, Miami, Florida, at the time of the incident. It employed 64 pilots and had a fleet of five Boeing 737 airplanes, including the incident airplane; the other four airplanes were Boeing 737-800 series.

The airline’s vice president of flight operations was responsible for the flying operations of the airline, flight crew training, the operations control center (OCC), and ground operations. The chief pilot, manager of flight operations training, director of inflight, OCC director, manager of flight standards, and manager of charter operations all reported to the vice president of flight operations.

At the time of the incident, Eastern Air Lines’ director of safety and security reported directly to the chief executive officer and was the only staffed position in the safety department. The director of safety and security had been hired about 2 weeks before the incident and was in the process of being trained by his predecessor, who had held the position from 2013 until September 2016. While he was being trained, the vice president of regulatory compliance served as the acting director of safety and security.

According to the vice president of flight operations and the manager of flight operations training, the Boeing 737 Flight Crew Training Manual and the Boeing 737 Flight Crew Operations Manual were used as the airline’s systems training material and procedures manual, respectively.

Safety Management

The FAA approved Eastern Air Lines’ safety management system (SMS) implementation plan in February 2016. The first segment of implementation included administering the SMS implementation plan and developing a tool (Aviation Resource Management Solutions) that was designed to help the company with safety risk assessment, assurance, and risk management. The former director of safety and security stated that, at the time of the incident, the first segment of the implementation was not fully realized and they were working toward an October 30, 2016, full implementation date.

Crew Resource Management (CRM) and EMAS Training

The manager of flight operations training at the time of the incident was also a check airman. He had been manager of training for about 1.5 years and had been with the company for 2 years.

The airline provided three courses on CRM: new hire, captain’s upgrade, and recurrent. The new hire CRM course consisted of a 2-hour segment covering CRM background, communications processes and decision behavior, team building and leadership, workload management and situational awareness, individual factors and stress reduction, and error management. The upgrade training included 1 day of ground school in which 1 hour was dedicated to CRM. Upgrade training also incorporated a captain’s leadership course that included content on the captain’s authority, briefings, workload management, and sterile cockpit procedures in accordance with 14 CFR 121.542, “Flight Crewmember Duties.” The recurrent training included a 3.5-day ground school for captains and first officers in which 1 hour was devoted to CRM training. All courses were taught using presentation slides, open discussion, and videos created by contracted training organizations.

The captain reported after the incident that he believed he and the first officer were working well as a crew during the trip. He stated that he did not call for a transfer of controls during the landing rollout and that, in hindsight, he should have. He further mentioned that he thought it was “OK” for both crewmembers to be applying brakes. The first officer reported a “lack of communication” during the landing rollout because the captain did not say that he was taking control of the airplane. Another Eastern Air Lines first officer who had flown with the captain before the incident described the captain’s CRM as “good.”

At the time of the incident, EMAS training was not part of Eastern Air Lines’ pilot training program. The captain stated during postincident interviews that he had forgotten that an EMAS was installed at the end of runway 22, that he had read about the systems, but had not had any training on them.

FAA Oversight

The former FAA principal operations inspector (POI) stated that he had been assigned to Eastern Air Lines before the company received its operating certificate. He stated that his duties included, most critically, surveillance and reviewing the airline’s manuals, including any changes to the manuals. He traveled to the airline’s headquarters about once or twice a week.

He also stated that he interacted most with the operations management, director of safety and security, and the CEO.

The former director of safety and security stated that during his time at Eastern Air Lines, he “seldom” interacted with the FAA POI or other FAA personnel. Other management personnel stated they interacted with the FAA daily or multiple times per week, via telephone, e-mail, or in person at the FAA’s office or at Eastern Air Lines’ office. The manager of flight operations training stated that he did not directly interact with the POI and usually went through the vice president of flight operations or the chief pilot. The vice president of flight operations stated that they had been assigned a new POI 5 months before the incident and that the interaction with the new POI was “really great.”

The FAA POI at the time of the incident reported that he mostly communicated with Eastern Air Lines’ director of flight operations and chief pilot but had also communicated with the director of flight training. He categorized the communication as “very good.” He added that Eastern Air Lines was the only certificate he managed and that FAA resources were limited such that they only had one person in the office who was able to conduct checkrides in the Boeing 737. He estimated that he was at Eastern Air Lines’ operations a “couple of times a week;” however, he had not taken part in Eastern Air Lines’ pilot training. He also stated that the training in the manual for a go-around was similar to the syllabus used by other airlines, and he “assumed” that they did some go-around training in the flare and some training in low visibility. The POI stated that, following the incident, he and Eastern Air Lines management had discussed training go-arounds once the airplane was on the ground and that further discussion was needed.

Additional Information

Sterile Cockpit Regulations

The CVR also contained conversation between the flight crew during the descent and approach below 10,000 ft that was not pertinent to the flight. Title 14 CFR 121.542, “Flight Crewmember Duties” states, in part, the following:

No flight crewmember may engage in, nor may any pilot in command permit, any activity during a critical phase of flight which could distract any flight crewmember from the performance of his or her duties or which could interfere in any way with the proper conduct of those duties. Activities such as…engaging in nonessential conversations within the cockpit and nonessential communications between the cabin and cockpit crews…are not required for the safe operation of the aircraft.

…critical phases of flight include all ground operations involving taxi, takeoff and landing, and all other flight operations conducted below 10,000 feet, except cruise flight.

Runway Condition Reports from Other KLGA Arrivals

Flight crews from four flights that landed on runway 22 within 10 minutes of the incident flight reported braking as “good” or “fair.” One crew reported noticing their airplane’s antiskid brake system pulsating during the landing rollout. Others reported that there was no hydroplaning or decrease in braking performance.


Automatic terminal information service (ATIS) “Bravo” was current when the first officer, who was the pilot flying, began to brief the instrument landing system approach for runway 22. The ATIS indicated visibility 3 miles in rain, ceiling 1,500 ft broken, overcast at 2,200 ft, wind from 130º at 9 knots, and that braking action advisories were in effect. The approach briefing included the decision altitude and visibility for the approach and manual deployment of the speed brakes by the captain, with the captain stating “you’re gonna do these. I’m gonna do this” to which the first officer replied “[that] is correct.” (The airplane’s automatic speed brake module had been deactivated 2 days before the incident and deferred in accordance with the operator’s minimum equipment list, which was appropriate).

The flight crew completed the approach briefing after descending through 18,000 ft mean sea level and completed the landing checklist when the airplane was near the final approach fix.

The airplane was configured for landing with the autobrake set to 3 and the flaps set to 30º.

ATIS information “Charlie” was current at that time and indicated visibility 3 miles in rain, ceiling 900 ft broken, overcast at 1,500 ft, and wind from 120º at 9 knots.

Flight data recorder (FDR) data and postincident flight crew statements indicate that the airplane was stabilized on the approach in accordance with the operator’s procedures until the flare. The airplane crossed the runway threshold at 66 ft radio altitude at a descent rate of 750 ft per minute. When the airplane had traveled about 2,500 ft beyond the runway threshold, its descent rate decreased to near zero, and it floated during the flare. Its pitch attitude started to increase in the flare from 2.8° at a radio altitude of about 38 ft, which is high compared to the 20 ft recommended by the Boeing 737 Flight Crew Training Manual. Further, the first officer didn’t fully reduce the throttles to idle until about 16 seconds after the flare was initiated and after the airplane had touched down. The initiation of the flare at a relatively high altitude above the runway and the significant delay in the reduction of thrust resulted in the airplane floating down the runway, prompting the captain to tell the first officer to get the airplane on the ground, stating “down down down down you’re three thousand feet remaining.”

The airplane eventually touched down 4,242 ft beyond the runway threshold. According to the operator’s procedures, the touchdown zone for runway 22 was the first third of the 7,001-ftlong runway beginning at the threshold, or 2,334 ft. Touchdown zone markers and lights (the latter of which extended to 3,000 ft beyond the threshold) should have provided the flight crew a visual indication of the airplane’s distance beyond the threshold and prompted either pilot to call for a go-around but neither did. The point at which the airplane touched down left only about 2,759 ft remaining runway to stop. The airplane’s groundspeed at touchdown was 130 knots.

The captain manually deployed the speed brakes about 4.5 seconds after touchdown and after the airplane had traveled about 1,250 ft down the runway. Maximum reverse thrust was commanded about 3.5 seconds after the speed brakes were deployed, and, with fully extended speed brakes and maximum wheel brakes (which were applied at main gear touchdown) the airplane achieved increasingly effective deceleration. Its groundspeed was about 35 knots when it entered the EMAS. With the effective deceleration provided by the fully extended speed brakes, maximum wheel brakes, and reverse thrust, the flight crew would have been able to safely stop the airplane if it had touched down within the touchdown zone.

The captain later stated that he had considered calling for a go-around before touchdown but the “moment had slipped past and it was too late.” He said that “there was little time to verbalize it” and that he instructed the first officer to get the airplane on the ground rather than call for a go-around. He reported that, in hindsight, he should have called for a go-around the moment that he recognized the airplane was floating in the flare. The first officer said that he did not consider a go-around because he did not think that the situation was abnormal at that time.

Training and practice improve human performance and response time when completing complex tasks. In this case, the operator’s go-around training did not include any scenarios that addressed performing go-arounds in which pilots must decide to perform the maneuver rather than being instructed or prompted to do so. Thus, the incident flight crew lacked the training and practice making go-around decisions, which contributed to the captain’s and first officer’s failure to call for a go-around.

Following the incident, the operator incorporated go-around training scenarios in which flight crews must decide to go around rather than being instructed to do so. The company’s director of operations also stated that the company has incorporated scenarios in which go-arounds are initiated from idle power and rejected landings are performed after touchdown with the automatic speed brake inoperative. It also added a training module emphasizing that “if touchdown is predicted to be outside of the [touchdown zone], go around” and intended to require a go-around if landing outside of the touchdown zone were predicted. The operator also intended to incorporate go-around planning into the approach briefing. Flight crews would determine the cues for the touchdown zone using the airport diagram and decide at which point they would initiate a go-around if the airplane had not touched down.

Given the known wet runway conditions and airplane manufacturer and operator guidance concerning “immediate” manual deployment of the speed brakes upon landing, the captain’s manual deployment of the speed brakes was not timely. NTSB analysis of FDR data for previous landings in the incident airplane determined an average of 0.5 second for manual deployment of the speed brakes. Using the same touchdown point as in the incident, post incident simulations suggest that, if the speed brakes had been deployed 1 second after touchdown followed by maximum reverse thrust commanded within 2 seconds, the airplane would have remained on the runway surface. Therefore, the captain’s delay in manually deploying the speed brake contributed to the airplane’s runway departure into the EMAS.

During the landing roll, the captain did not announce that he was assuming airplane control, contrary to the operator’s procedures, and commanded directional control inputs that countered those commanded by the first officer. The captain later reported that he had forgotten that an EMAS was installed at the end of runway 22 and attempted to avoid the road beyond the runway’s end by applying right rudder because he thought it would be better to veer to the right. However, the first officer applied left rudder to maintain alignment with the runway centerline and to counter the airplane pulling “really hard” to the right because of the captain’s inputs. The breakdown of crew resource management during the landing roll and the captain’s failure to call for a go-around demonstrated his lack of command authority, which contributed to the incident.

At the time of the incident, EMAS training was not part of the operator’s pilot training program, but such training was added after the incident. The circumstances of this event suggest that the safety benefit of EMASs could be undermined if flight crews are not aware of their presence or purpose.


The National Transportation Safety Board determines the probable cause(s) of this incident to be:

The first officer’s failure to attain the proper touchdown point and the flight crew’s failure to call for a go-around, which resulted in the airplane landing more than halfway down the runway. Contributing to the incident were, the first officer’s initiation of the landing flare at a relatively high altitude and his delay in reducing the throttles to idle, the captain’s delay in manually deploying the speed brakes after touchdown, the captain’s lack of command authority, and a lack of robust training provided by the operator to support the flight crew’s decision-making concerning when to call for a go-around.


Aircraft Landing flare – Not specified (Factor)

Personnel issues Use of policy/procedure – Copilot (Cause)

Use of policy/procedure – Flight crew (Cause)

Lack of action – Flight crew (Cause)

Delayed action – Copilot (Factor)

Delayed action – Pilot (Factor)

Decision making/judgment – Pilot (Factor)

Organizational issues Recurrent training – Operator (Factor)

Excerpted from National Transportation Safety Board Aviation Incident Final Report  DCA17IA020


  1. Let’s go around
  2. The Organizational Influences behind the aviation accidents & incidents
  3. Speaking of going around
  4. Going around with all engines operating


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


Out of line

Some personal issues will continue to keep me out of line for a while. Hope they resolve completely in no long time so I’d be able to publish again soon. Thanks a lot for reading me.


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

Let’s go around

Runway excursion has been the most frequent category of aviation accidents for many years now, and according to Flight Safety Foundation studies 83% of these accidents could have been prevented with a go-around. Moreover, 54% percent of all accidents could be prevented by going around, meaning the go-around is perhaps one of the most critical strategies in preventing aviation accidents.

Go around

Photo from Radko Našinec video Crosswind landing results in almost crash / Boeing 737 hard touchdown + go around, Prague (LKPR)

However, compliance with go-around policies is extremely poor among the industry, only 3% of unstable approaches result in go-around policy compliance.

On the other hand, going around is not risk-free. During the go-around, there is an increased risk of loss of control-LOC events, as we have seen in several major accidents in the last two decades, but there are risks of controlled flight into terrain-CFIT and midair collision-MAC too.

As Flight Safety Foundation states, in the Go-Around Decision-Making and Execution Project final report, these risks associated with conducting a go-around could be triggered by:

  • Ineffective initiation of a go-around, which can lead to LOC;
  • Failure to maintain control during a go-around, which can lead to LOC, including abnormal contact with the runway or to CFIT;
  • Failure to fly the required track, which can lead to CFIT or MAC;
  • Failure to maintain traffic separation, which can lead to MAC; and,
  • Generation of wake turbulence, which may create a hazard for another aircraft that can lead to LOC.

Therefore, the go-around decision should balance the risk associated with the continuing to land with the risk associated with the go-around itself.

Besides the operational, procedural and technical aspects, there are several Human Factors issues associated with a go-around decision and execution. These Human Factors lessons have been learned from incidents and accidents associated with going around and have been studied further and thorough by several organizations around the world. Let’s review some of them:

  • Although a go-around is considered as a normal procedure, a BEA study showed that a go-around does not often occur during operations, could be complex in terms of workload and is one of the maneuvers that are poorly represented by simulators. For all these reasons, “in practice, the go-around procedure is not a normal procedure but a specific one”. (Bureau d’Enquêtes et d’Analyses (BEA) pour la Sécurité de l’Aviation civile. Study of Airplane State Awareness during Go-Around. August 2013)
  • A go-around is a normal but no routinely executed procedure for most commercial pilots. A long-haul commercial pilot may conduct one go-around every two to three years whereas a short-haul commercial pilot may conduct a go-around once or twice a year. (Flight Safety Foundation Go-Around Decision-Making and Execution Project final report)
  • Is poorly represented by full flight simulators, due to no realistic ATC environment and the SIM inability to represent the physiological sensations associated with a go-around
  • Produces a disruption that often is unexpected by the flight crew, therefore, can induce the startle effect
  • It breaks the continuity of tasks being performed and suddenly demands a new set of actions with discontinuous tasks and disrupted rhythms of execution
  • It comprehends many tasks of different nature which must be performed in a limited period of time
  • The maneuvers required are varied and must be performed rapidly
  • The parameters that must be controlled are numerous and rapidly changing
  • Besides to monitor attitude, thrust, flight path, aircraft configuration and pitch trim, pilots have to monitor the autopilot, the flight director, the autothrottle, their modes, cross check one to each other and the airplane to be sure they themselves and the plane are doing the right thing
  • All of the above could produce an information overload, high workload and stress especially when the startle effect is also present
  • This sudden high workload is higher for the Pilot Monitoring-PM than that for the Pilot Flying-PF. PMs have to deal with the readbacks of ATC instructions, the callouts, the monitoring of the PF’s flight control, the verification of the pitch attitude and the verification of flight mode annunciator (FMA) modes. This high workload often prevents the PM from fulfilling the task of monitoring the PF
  • As stress can reduce the ability to execute complex actions, the higher the level of stress the higher the performance can be compromised
  • Stress also could lead to attention channelling which produces excessive focusing on some task while neglecting others
  • “Automatic systems could add to the problems because their initial engagement modes are different from those expected for the go-around … and when they are neither called out nor checked, this leads the aeroplane to follow an unwanted flight path” (BEA Study on Aeroplane State Awareness During Go-Around)
  • All these, the startle effect, the time pressure, the automation issues, the cognitive overload, the potentially overwhelming situation could produce a degradation of CRM skills
  • Spatial disorientation could be an aggravating factor
  • Somatogravic illusions induced by the linear acceleration produced by the full thrust, maybe in a relatively light at the end of a flight plane, can cause the PF to reduce the pitch angle. This may induce loss of control during the go-around. Full flight simulators lack the ability to accurately represent a somatogravic illusion
  • Low relevant experience of one or both pilots can affect the effectiveness of monitoring during go-around
  • Complex arrivals, departures and go-around procedures increment the workload for the flight crews and could be another aggravating factor
  • In the same way, the intervention of ATC with too much information in a radio transmission can lead to pilot confusion
  • Changes to go-around instructions increase the already high workload for pilots. Same could happen with late provision of go-around instructions
  • Sometimes ATC instructions are not compatible with aircraft performance
  • Bringing out unpublished go-around tactical instructions can place high demands on pilots

The decision to go around is perhaps the one with most impact has in aviation accident reduction. How can the risk associated be mitigated and how compliance with go-around policies can be improved?

Answering that question is obviously far beyond the scope of this article. There are now numerous studies on the subject with the results of research, findings and analysis, with proposed strategies and recommendations for the industry, the regulators, the operators, the flight crews and the air traffic services providers. Nonetheless, several factors can be stressed and highlighted here:

  1. “Pilots and their employers should understand that one of the many reasons that violating approach minimums is unacceptable is because evidence indicates that if a go-around then becomes necessary, the chances of a safe transition to the go-around are reduced.” (Flight Safety Foundation Go-Around Decision-Making and Execution Project final report). So NOT violate approach minimums
  2. “The lack of decision is the leading risk factor. In other words, if you’d made your decision earlier in the process, you’d probably able to execute the go-around better than forced into it by having an unstabilized approach, then, at the very last second, deciding have to go around,” (Dave Carbaugh, presentation to Flight Safety Foundation’s 67th annual International Air Safety Summit, 2014) So DO NOT delay the decision, it could prevent the situation to escalate.
  3. “Ensure that go-around training integrates instruction explaining the methodology for monitoring primary flight parameters, in particular, pitch, thrust, then speed.” (BEA Study on Aeroplane State Awareness During Go-Around) It seems obvious, but apparently, it has not been.
  4. “Ensure that go-around training and awareness appropriately reflect different go-around execution risk scenarios” (Flight Safety Foundation Go-Around Decision-Making and Execution Project final report) 
  5. Enhance training “… including realistic detailed training scenarios based on current technology and risks” (BEA Study on Aeroplane State Awareness During Go-Around)
  1. “Review go-around policy, procedures and documentation to maximize their effectiveness, clarity and understanding.” (Flight Safety Foundation Go-Around Decision-Making and Execution Project final report)
  2. “Study the additional technical and regulatory means required to mitigate the shortcomings of CRM in high workload and/or unusual conditions” (BEA Study on Aeroplane State Awareness During Go-Around)
  3. “Air traffic controllers, except where necessary for safety reasons, do not give instructions that are in contradiction with the published missed-approach procedure; and that, when necessary, the instructions are announced to crews as early as possible during the approach.” (BEA Study on Aeroplane State Awareness During Go-Around)

As Captain Dave Carbaugh, stated in his presentation to Flight Safety Foundation’s 67th annual International Air Safety Summit (IASS) in Abu Dhabi, United Arab Emirates, in November 2014 “30 years ago we had low thrust-to-weight ratios, so the airplane just didn’t climb very quickly. We had less traffic density, so there wasn’t anybody in front of you and … and a lot of times, the go-round was non-complex. ‘Fly runway heading to 4,000. It was basically easy. But those days are gone…”


  1. Blajev, Tzvetomir, Curtis, William. Go-Around Decision-Making and Execution Project. Final report to Flight Safety Foundation. March 2017
  2. Bureau d’Enquêtes et d’Analyses (BEA) pour la Sécurité de l’Aviation civile. Study of Airplane State Awareness during Go-Around. August 2013
  3. Rosenkrans, Wayne. Go-Around Risks. AeroSafety World April 2015. https://flightsafety.org/asw-article/go-around-risks/


  1. MyCargo B744 fatal accident at Kyrgyz Republic, Jan 16th, 2017. Preliminary Report
  2. Going around with no thrust. Emirates B773 accident at Dubai on August 3rd, 2016, interim report
  3. The Head-Up Illusion: do you remember it?
  4. Armavia A320 crash during go-around at night in poor meteorological conditions
  5. Tatarstan B735 crash during go-around at night. Learning from the recent past
  6. Going around with all engines operating
  7. Speaking of going around
  8. Loss of flight crew airplane state awareness 


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

Women and aviation safety

woman in comandPhoto: Elizabeth L. Remba Gardner, Class 43-W-6 WASP (Women Airforce Service Pilot) at the controls of a Martin B-26 ‘Marauder’ medium bomber. Harlingen Army Air Field, Texas. 1943

In 2013, the United States Army published a study on the role of women in combat, which shows how, in the years 2002 to 2013 women were involved in fewer aviation accidents than male crews, only 3% of accidents. With women accounting for approximately 10% of flyers, the evidence could suggest, according to the study, that women can operate an aircraft more safely. Concerning only the AH64-APACHE, 100% of the accidents in the garrison and in the theater of operations, involved male crews, which would suggest, according to the author of the study, that female attack pilots could be even More secure in the performance of flight activities. (1)

Is this a generalized tendency or is it specific to the population studied?

In 1986 a study was published in which, when analyzing by gender the NTSB files of all general aviation accidents occurring between 1972 and 1981, a higher accident rate was found in men than in women and a higher rate proportion of deaths or serious injuries in the accidents of male pilots in those of female pilots. These differences were found in all variables analyzed: type of license, age, total flight time, flight time in aircraft type, operating phase, flight category, specific cause and causal factors. (2)

On the other hand, a study published in 1996 analyzed if there were differences in the accident rate between male and female airline pilots in the United States, based on the analysis of information obtained from the FAA on accidents between 1986 and 1992. Initially, it was found that in general women hired by major airlines had significantly higher accident rates than men. However, the study emphasizes that on average women were much younger and less experienced than male pilots, whereby male pilot accidents were adjusted for age, experience (total flight time), risk exposure (hours flown in the previous 6 months) and airline (major airline vs non-major airline), using logistic regression. After adjusting the variables it was found that there is no difference in the rate of accidents of female and men pilots, which suggests that neither women nor men are a safer group than the other. (3) (NOTE: Logistic regression is a special type of regression that is used to express and predict the probability between two groups that an event occurs, given a series of independent variables)

The same author published in 1997 a similar study analyzing this time the incident rate in a population of 70,164 airline pilots. The regression analysis again indicated that there are no significant differences in performance between female and male airline pilots. (4)

On the same track, in 1998 Caldwell & Le Duc found that in combat pilots, gender did not produce significant operational effects on flight or mood performance and the ability to cope with stressors associated with combat. (5)

However, for general aviation, the causes of air accidents do seem to be related to gender, as shown in a study published in 2001 in which the fatal and non-fatal per capita accident rate was higher in men than in women (3,20), which would confirm the findings of the 1986 study previously mentioned (6)

Finally, in 2002, a study was conducted at Embry Riddle Aeronautical University which found that there are no aspects of a captain’s competence that are related to gender. The author of the study even poses the possibility that this lack of difference in performance is due to the personality traits present in pilots, whether men or women. The above, based on a study that showed through psychological tests that the personality profile of female drivers has little resemblance to the profile of adult women in the US, followed by a high resemblance to the profile of adult men in the US and with the closest resemblance to the male pilot profile. This personality similarity, says the study’s author, may have eliminated differences in skills that have been apparent in other work groups that do not require, attract, and select such a specific personality type.

female 1

Photo: Capt Kerstin Felser

Based on the above we could conclude that although for some types of aviation it is true that pilots show better performance indices than their male counterparts, this difference does not occur in commercial aviation. Better yet, there is no reason to think that there is any difference in performance capability between airline pilots of both genders.

Therefore, there is no reason to prefer one over another in the selection processes to enter the airline aviation that is the one that occupies us, and that for obvious reasons, generates more attention in the public, the media and the Governments.

So why are not there more female pilots? I do not have the answer to that question, but I can tell you that for reasons of air safety, it is not.

Although there is still controversy about whether or not there are differences in gender-related cognitive skills, any variation that exists has very little relevance in air operations. (Caldwell & LeDuc, 1998).


  1. Peña-Collazo, Seneca. Women in Combat Arms: A Study of the Global War on Terror. A Monograph.S. Army, School of Advanced Military Studies. United States Army Command and General Staff College. Fort Leavenworth, Kansas. January 2013. Page 47
  2. Vail GJ, Ekman LG, Pilot-error accidents: male vs female. Applied Ergonomics. 1986 Dec;17(4):297-303.
  3. L. McFadden, Comparing pilot-error accident rates of male and female airline pilots. Omega Volume 24, Issue 4, August 1996, Pages 443-450.
  4. Kathleen L. McFadden, Predicting pilot-error incidents of US airline pilots using logistic regression. Applied Ergonomics Volume 28, Issue 3, June 1997, Pages 209-212
  5. Caldwell JA Jr, LeDuc PA, Gender influences on performance, mood and recovery sleep in fatigued aviators. 1998 Dec;41(12):1757-70.
  6. Baker SP, Lamb MW, Grabowski JG, Rebok G, Li G, Characteristics of general aviation crashes involving mature male and female pilots. Aviation Space and Environmental Medicine. 2001 May;72(5):447-52
  7. Paulsen, Marianne, Perception of Competence in Male and Female Pilots: Between Group Differences. Embry-Riddle Aeronautical University – Daytona Beach. Spring 2002


This is a translation of the article Mujeres y Seguridad Aérea, which was originally published on SEPLA-Sindicato Español de Pilotos de Linea Aérea (Spanish Airline Pilots Union) website.


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

Can aviators life and home-based stressors impair aviation safety?


Photo US Air Force

On a scheduled passenger flight, shortly before the descent into Dublin (EIDW), the Co-pilot of a Bombardier DHC 8-402 (Q400) began to feel unwell and requested to leave the flight deck for a few minutes. Before the Co-pilot left his seat, the Commander felt an unexpected aircraft upset in the form of a yaw and roll to the left. The Co-pilot, who had become incapacitated, had inadvertently made an input to the left rudder pedal. The Commander returned the aircraft to normal flight and the aircraft landed without further incident. There were no injuries. The investigation authority stated that the Co-pilot was probably under some stress on the morning of the flight considering that his young child had a hospital appointment the following day and that stress and lack of quality sleep may have been factors in his feeling unwell and incapacitation during the flight. (See: Stress and lack of quality sleep, factors leading to serious incident)


Life-stress is defined as physical and psychological symptoms that are often a product of difficult life circumstances. Some of this symptoms can be, muscle tension, worry or preoccupation, disrupted sleep and fatigue, change in appetite, or alterations in social interactions such as withdrawal, irritability, or difficulty concentrating.

Can life stressors impair aviation safety?

Pilots are often reluctant to report physical complaints or illnesses because of fear of being temporarily or definitely grounded. Now let‘s consider the aviator who struggles with psychological or emotional issues, it may be even more difficult. Losing flying status is one of the greater fears for any pilot. Can this lead to dangerous situations because aviators are very reluctant to seek help for these problems?

It might be assumed that higher levels of life stress substantially increase vulnerability to error, but many aviators claim that they can compartmentalize to protect performance. What does the research literature tell us about this issue?

Home-based stressors are important chronic stresses for a pilot and should be given consideration when studying the relationship between the pilot, work effectiveness, and safe performance. The study of the degree and effect of home stress on job performance is a necessary part of preventive aviation safety and efforts to create a more effective workplace.

But, only limited research has examined the effects of life stress on skilled performance. Moreover, despite the importance placed on the family as a social support, there has been a little systematic study of the relationships between the pilot’s family life, workplace stress, and performance.

The latter can be a consequence of methodological and ethical limitations inherent in the experimental manipulation of life-stress. This is not a subject easily studied in the laboratory or the field.

There could be at least three specific reasons to explain why strong evidence for a connection between life-stress and performance has been elusive:

(1) Difficulties in the measurement of life-stress

(2) Individual differences in reactions to stressors

(3) Luck. Probably the influence of life stress will go undetected because it only infrequently joins with other circumstances to cause a mishap.

The fact that pilots are unlikely to report stress symptoms makes the life-stress–performance relationship even more difficult to investigate. This under-reporting could occur for at least two reasons:

(1) It is possible that pilots are not fully aware of the effect that stress has on them

(2) Even when they are aware of these effects, a variety of internal and external pressures make it less likely that a pilot will report or seek help for symptoms

Since 1969 several authors have suggested a relationship between life stress and pilot performance but most of these studies suffer from methodological problems. Therefore, confidence in their interpretation and conclusions are limited. The most rigorous studies provide only correlational data which does not allow inferring causality. None the less, the lack of strong empirical support does not mean that life-stress does not impair performance, and a causal relationship might be revealed with other methods.

In the mean time let’s review some of these studies about how life stress affects performance that, as stated before, have provided correlational data that is noteworthy.

There have been many hypotheses about how life stress affects pilot performance. Several authors have suggested that those experiencing life stressors may be more likely to commit errors because they are likely to be thinking about the stressor rather than devoting all of their cognitive resources to the task at hand. A senior U.S. Air Force flight surgeon suggests that, while pilots may have some ability to keep life-stressors from entering the cockpit and interfering with performance, each also has a level of stress or a specific stressor that is likely to significantly interfere with this ability to compartmentalize. Another author contends that even high-functioning pilots under some combination of stresses—intrapersonal or interpersonal—may develop personality reactions, anxiety and somatic symptoms, which reduce effectiveness and produce inadequate functioning and other hypothesize that stress indirectly impairs performance by disrupting sleep and impairing one‘s ability to pay attention.

Several US Navy studies explored the influence of personality and life changes on the likelihood of having an accident. Results indicated that certain items discriminated between those who were causally involved in aircrew error accidents and those who were not. Five items were more likely to be causal:

(1) Recently became engaged

(2) Made any recent decisions regarding the future

(3) Have difficulty with interpersonal relationships

(4) Recently have a death in the family or recently lose a close friend through death

(5) Recently have trouble with superiors or recently have trouble with peers or subordinates.

Another study surveyed 8,800 Canadian airline transport, commercial and senior commercial, helicopter and private pilots in an attempt to establish a link between certain life events, pilot characteristics, and accidents. While the analysis revealed many accident markers, preoccupations about separation, divorce or business decisions appeared most frequently. Although it‘s impossible to determine the direction of the relationship (Did accidents prompt preoccupation with a business decision or vice versa?), it is noteworthy that many of these background stressors and accidents are frequently correlated.

Across the Atlantic one study discussed results from 149 British military flying accident investigations. The author reported a direct link between a stressful life event and accidents in two cases and life stress as a possible contributing factor in 11% of the accidents.

Near in space and time was completed an in-depth study of various sources of stress and coping mechanisms in British commercial pilots. The authors found that home-based factors were important in both their impact on work itself and on the ability to cope with stress. While there were many interesting findings, some appear particularly relevant to the discussion of pilot‘s perception of the stress–performance relationship.

Taking into account those that answered the symptoms occurring “usually” or” almost always”, some of the findings are:

  • 2% of the pilots said they could tell when they experienced stress because at work they usually or ―almost always felt tired
  • 1% said they experienced recurring thoughts during periods of low workload
  • 1% experienced a tendency to not listen as intently
  • 4% had a tendency to worry
  • 4% reported decreased concentration
  • 2% reported becoming detached from tasks at hand.

When the pilots who reported these symptoms occurring “sometimes” are included, the percentages increase substantially. For example, using this less conservative approach, over 45% indicated that they experienced decreased concentration at least sometimes as a result of stress. Nearly 93% indicated that they thought negative life events could affect pilot performance. The authors suggest that many of the noted effects are cognitive in nature.

Back in America, a study of U.S. civilian pilots examined the effects of corporate instability on commercial pilots by contrasting pilots from stable airlines with pilots from unstable airlines. The authors noted substantial and statistically significant differences between the two groups. Pilots from unstable airlines were far more likely to report symptoms such as feeling hopeless about the future, irritability, inability to concentrate, decreased attention, excessive anger, procrastination, general dissatisfaction, crying easily or feeling like crying, and having a pessimistic attitude.

The FAA published a study which purpose was to examine the relationship between self-reported home stress, work stress, and perceived performance in U.S. coast guard (USCG) pilots. The results showed that as Home Stress scores increased, so did pilots’ rating of Job Stress. However, neither Home Stress nor Job Stress, by itself, was significantly related to self-reported Flying Performance. However, pilots perceived their own Flying Performance to be detrimentally affected when stress in the home carried over to the work setting. The more home stress was felt in the workplace (Home Stress at Work), the higher pilots’ ratings of Job Stress.

Specific life/home stresses

Life stress is a product of difficult life circumstances. Among those circumstances are relationship difficulties, financial worries, health concerns, bereavement issues, work related problems, and separation from family. Also, irregular duty periods and missing out on activities at home can spur a significant and detrimental cycle of stress.


Photo Daily Record 

Stability at home often is undermined by the nature of the profession. Stability is difficult to achieve when dealing with extended absences or irregular duty periods. Demanding schedules with very little flexibility could have social consequences that often are not appreciated by those who work 9-to-5. Moreover, many people who work rotating shifts reduce their social activities because such schedules do not allow consistent involvement, which can lead to a feeling of social isolation. Limiting relationships to workplace colleagues can also lead to feelings of social isolation among the family.

On the other hand, it is common to end a duty cycle or shift period feeling too exhausted to participate in family functions, this can cause spouses and children to feel neglected. This is especially true when the duty period occurs between 1500 and 2300 while the family is home and family and evening social activities are missed. Friends or relatives with no exposure to the same lifestyle may not understand.

The “intermittent husband syndrome” is an example of situations common to professions in which a spouse is regularly away from home for extended periods. The much-anticipated reunion can create as much stress as joy. In situations where male pilots are away and their female partners are left at home, research suggests that families suffer from more stress-related illness and marital difficulties than those where husbands do not travel. Family routines become disrupted, with negative effects on wives and children.

In addition to these known effects of irregular duty periods, the way aviation jobs can consume attention while on duty and affect personalities while off duty may often produce difficulty in readjusting to life back at home.

Aviation professionals often experience high job demands, inflexibility and time pressure. They live with strict deadlines, often balancing conflicting demands, and stress is the body’s natural response. Stress, combined with the competitive “Type A personality” so common in the industry, can take a toll on physical or psychological health, or on satisfaction with the job or with a marriage. The inability to meet family obligations because of the time and energy required for work compounds the stress felt on the job. A vicious cycle can develop.

One study asked pilots to rank order the sources of stress in their lives. Of the 53 items in the questionnaire only 14 items related to domestic stress even so 7 domestic stress items were among the top ten stressors. The top three ratings of the most stressful situations were domestic stress items. They were

(1) Death of a child

(2) Death of a mate

(3) Death of a parent

In the FAA study previously mentioned of the 29 items measuring home stress the following were found as causing much stress and very much stress:

  • Build up of tasks, duties, and things to do
  • Degree to which home life is way I want it
  • Quality of relationship with partner
  • Lack of money
  • Disappointed others don’t meet expectations
  • Constant, ongoing irritations
  • ‘Good’ use of time at home and how spent
  • Conflicts of interests, resulting compromises
  • Issues associated with children
  • Others not obeying / things that go wrong

How home stress is experienced at work

The most frequently reported ways in which home stress was felt at work were fatigue and rumination about the home based stress.

As found in the civilian British pilots cited previously, the FAA study found that about one-fifth of pilots reported that they could usually or always tell when they were experiencing home stress at work by experiencing the following symptoms:

  • Feeling tired due to disrupted sleep
  • Having a tendency to worry
  • Intruding thoughts during low workload.

On the other hand items of home stress at work that were significantly correlated with poorer flying performance were

  • Tendencies to worry at work
  • Not listen as intently
  • Feeling slowed down at work

Meanwhile, home stress at work was significantly and negatively related to specific flying performance items of:

  • Being ahead of the game
  • Smoothness and accuracy of landings
  • Degree of airmanship exhibited
  • Ability to divide attention

Other symptoms noted by several authors were:

  • Irritability
  • Inability to concentrate
  • Decreased attention
  • Memory difficulty


Photo Adventures of Cap’n Aux

By what mechanisms might life stress impair performance?

There are hints in the studies described above that cognitive processes may be affected by life-stress.

With regard to mechanisms by which life stress may impair performance several researchers found that pilots report concentration and attention management issues when under life stress. Also, some evidence suggests that life-stress may negatively influence underlying cognitive processes such as information processing, working memory, problem-solving and decision-making. To the degree that these important processes are affected, it might be expected an associated decrement in performance.

Additionally, there is evidence suggesting that life-stress disrupts sleep and leads to increased levels of fatigue, which in turn impairs cognitive and social performance.

Studies offer some support for the notion that life-stress might impair performance by diverting attention from the task at hand or by pre-empting working memory. If we cautiously extend these findings to pilots performing real world tasks, it is possible that pilots may pay more attention to stress-related thoughts (e.g., thinking about relationship problems, a recent argument, problems on the job) or to increases in autonomic arousal. Acting as a secondary task, these preoccupations would divide attention and lead to deficits in working memory capacity, making it more probable that a pilot might fail to notice critical phenomena and forget to perform tasks that are not strongly cued by the environment.

There are several potential routes by which life-stress may directly or indirectly impair performance:

  1. It may lead to decreased quantity and quality of sleep, leading to a state of fatigue, which is known to impair performance in specific ways.
  2. It may undercut motivation to perform one‘s job well. While the approach to tasks perceived to be critical may not change, tasks viewed as less significant (e.g., following checklist procedures) may receive less attention than is appropriate.
  3. It may negatively influence affective state, leading to higher levels of frustration, irritability/ anger, anxiety, or depression. These mood states can negatively influence the interpersonal atmosphere in the cockpit, potentially leading to ineffective crew resource management. To the degree that life-stress creates a sense of dissatisfaction, pessimism and depression, motivation and task engagement may decrease. A crewmember may become more hostile or withdrawn, creating an interpersonal environment that might lead to a less than the optimal exchange of important task–related information.
  4. Life-stressors may increase levels of off-task thinking or worry, which acts to divide finite attentional resources necessary for acquiring new information and effectively managing tasks.
  5. Efforts to suppress unwanted (stressful) thoughts consume a portion of finite cognitive resources, thereby impairing task performance.
  6. Emotionally draining events, such as arguments with a spouse or boss, may cause fatigue or demotivation.

In other words, demands at home can produce preoccupied, distracted and fatigued workers, a perilous condition in a safety sensitive job.

Coping strategies

The importance of home life in mediating stress was also seen when pilots rated the importance of various coping strategies. Stability in relationships and home life were the most important factors in helping pilots cope with stress.


Photo U.S. Air Force

From a list of 33 coping strategies, over 80% of pilots rated 11 coping mechanisms as having importance to paramount importance. The three most important strategies all involved family support. The first two, stability of relationship with spouse and a smooth and stable home life, were rated as important to paramount importance by 100% of the pilots. The third item, talking to an understanding spouse or partner, was rated as important to paramount importance by 89% of the pilots.

Potential coping strategies, such as fostering stability at home, often are undermined by the nature of the profession. As a pilot’s partner/spouse support system became less effective, the pilot began to lose the most important ways of coping with stressors. It might be speculated that, if home-based stress increases significantly and partner support lessens, the pilot’s cognitive functioning may be at risk for compromise and reduced efficiency. If additionally, the pilot may be moving closer to a negative significant life event such as divorce, separation, or alienation, the possible ramifications on cockpit error could be even higher.

Other coping mechanisms rated as very useful in coping were:

  • Psychological detachment (physical separation from the workplace and mental disengagement through activities that put focus on something else)
  • Sleep
  • Planning ahead
  • Working things out by logic
  • Physical pastimes/exercise
  • Partner efficient at looking after things

Coping strategies significantly correlated with higher ratings of flying performance were spouse/partner who had prior knowledge of flying or who flies and hobbies. The coping strategy of living in a nonflying social environment was significantly related to a lower Flying Performance score.

It is suggested that the first warning signs of home-based psychological distress may be more evident in the daily work activities rather than in cockpit error. If support services and management recognized the early warning signs at work that were symptomatic of home-based stress, they could provide timely intervention before the occurrence of more serious flying performance decrements.

Certainly, continued support of family and home services will have beneficial effects.

Having a better appreciation of the effects of life stress on skilled performance is underscored by the likelihood that the majority of skilled performers are prone to under-report such effects. Aviators will be much more likely to acknowledge the effects of life–stress to the degree that their organizations destigmatize emotional and psychological issues and improve the medical community‘s handling of these cases.

The importance of stress to pilot job performance has been an aviation safety issue for many years often discussed under the category of pilot error or human factors. However, many questions remain regarding the relationship between life stress and flying performance.

The interconnections of stress variables and their effects on flying performance are undoubtedly very complex. Moreover, subjects cannot be randomly assigned to levels of life stress; thus, other undetermined variables may co-vary with stress.

Even for the most expert or skilled performers, it is likely that cognitive processes, at one time or another, will be affected by life stress in a way that impairs performance. We must continue to look for better methodologies and should not dismiss the potential influence of life stress on performance because of the current lack of strong empirical data

Further research into the impact of the family as both a source of stress and support could help the aviation community make wise policy decisions regarding family-work issues and appropriate intervention, giving insight into the interplay of the pilot’s coping strategies and personal support system.


Excerpted from:

  1. The Effects of Life-Stress on Pilot Performance. James A. Young. NASA Ames Research Center, Moffett Field, California. December 2008
  2. The relationship between aviator’s home-based stress to work stress and self-perceived performance. Fiedler, E.R., Della Rocco, P.S., Schroeder, D.J., & Nguyen, K.DOT/FAA/AM-00/32. Oklahoma City, Oklahoma, US. U.S. Federal Aviation Administration (FAA). October 2000
  3. On the Home Front. A stressful family life can affect performance in the cockpit. Patrick Chiles. AeroSafety World August July–August 2011.


  1. Stress and lack of quality sleep, factors leading to serious incident
  2. Sleep loss in aviation. Let’s review


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

Sleep loss in aviation. Let’s review

On January 25, 2016, in darkness and hazy weather conditions, the flight crew of an ATR 72 lined up the aircraft on the runway edge lights along the right-hand side of runway 27L instead of the runway centerline lights of runway 27L.

This resulted in a misaligned take-off roll over the elevated runway edge lights along the right-hand side of runway 27L leading to damages to the runway edge lights and the aircraft itself.

A combination of environmental, operational, and human factors contributed to the sequence of events:

– Dark night operation

– Reduced visibility

– Runway and taxiway environment, including an extra tarmac width on runway 27L, the absence of runway shoulder markings, the absence of taxiway centerline lighting, and the use of a displaced threshold

– Flight crew divided attention unintentionally provoked by the before take-off procedures and checks

– Flight crew fatigue

The serious incident occurred in dark night and under instrument meteorological conditions (IMC).

Despite the fact that the actual flight and duty time of the flight crew did not violate any flight and duty time requirements, the Danish Investigation Authority considered the flight crew to be fatigued in the morning of the accident day. Because of fatigue, flight crew performance was impaired equivalent to more than 0.05% blood alcohol concentration impairing flight crew vigilance and reaction times and might have impaired the flight crew decision- making process and the flight crew night vision adaptation and visual acuity.

(See: Pilots fatigue lead to a Danish Air Transport ATR 72 serious incident)


Sleep loss and circadian disruption created by flight operations can degrade performance and alertness, we all know that. Scientific examination of these psychological/physiological parameters has established a direct relationship between their degradation and errors, incidents and accidents. We all know that, too. Nevertheless, despite that knowledge, fatigue remains an ever present danger in flight operations.

The operational demands of the aviation industry and the growth in global long-haul, regional, overnight, and short-haul operations will continue to increase the 24hour/7days requirement on flight crews. Therefore, shift work, night work, irregular work schedules, unpredictable work schedules, and time zone changes will continue to be commonplace components of the aviation industry. These factors pose known challenges to human physiology, and because they result in fatigue and performance impairment they pose a risk to safety.

Extensive data are available that clearly establish fatigue as a significant safety concern in all modes of transportation and in 24-hr shift work settings. The safety risk posed by human fatigue in transportation has been recognized and addressed over 100 years. Its 24/7 operational demands can easily lead to degradation or impairment in all aspects of human capability particularly cognitive performance including decision-making, attention, reaction time, learning, memory and communication skills. When individuals performing safety-critical functions are affected by fatigue, there is a high risk of fatalities, injuries and environmental hazards as a result of accidents or incidents.

Additionally, there are other associated costs of fatigue, such as the financial costs of reduced productivity and potential liability issues.


On 2006 a study at UCE Birmingham on the effect of fatigue on 162 short-haul pilots reported 75% of the pilots had experienced severe fatigue with 81% considering the fatigue to be worse than two years previously.

On 2012 the European Cockpit Association carried out a survey about self-assess of the level of fatigue experienced by pilots. More than 6.000 European pilots were surveyed between 2010 and 2012 and the results were published as Barometer on Pilot Fatigue. Some of the survey results are:

  • Over 50% of surveyed pilots reported having experienced fatigue as impairing their ability to perform well while on flight duty.
  • 4 out of 5 pilots reported having coped with fatigue while in the cockpit, according to polls carried out in Austria (85%), Sweden (89%), Germany (92%) and Denmark (93%).
  • In the UK (43%), Denmark (50%), Norway (53%) and Sweden (54%) the surveyed pilots reported falling asleep involuntarily in the cockpit while flying. In the UK, a third of the pilots said to have woken up finding their colleague sleeping as well. 65% of Dutch and French pilots stated they have trouble with “heavy eyelids” during flight.
  • 70-80% of fatigued pilots would not file a fatigue report or declare to be unfit to fly. Only 20-30% will report unfit for duty or file a report under such an occurrence.
  • More than 3 out of 5 pilots in Sweden (71%), Norway (79%) and Denmark (80-90%) acknowledge having already made mistakes due to fatigue, while in Germany it was 4 out of 5 pilots.

On August 2013 was published the study Prevalence of Fatigue in a Group of Airline Pilots based on a 2012 survey of 1500 commercial airline Portuguese pilots, commanders (captains) or first officers between the ages of 20 and 65 who were on active duty and had flown during the previous six months. The assessed their fatigue using the nine-item Fatigue Severity Scale. Some of the results of the study are:

  • More than 90 percent reported having made fatigue-related mistakes in the cockpit
  • 66% said that they had more than once been so tired that they should not have been at the controls
  • Despite they admitted having been fatigued while flying, 82% said they had never reported themselves as “unfit for flight as a result of accumulated fatigue,” and only 11 percent said they had done so only once
  • Pilots flying medium- and short-haul flights —typically less than six hours long with multiple legs — reported higher levels of fatigue than those who flying long-haul flights

The US National Sleep Foundation published in March 2012 a 1,087 transportation professionals poll, which included 220 pilots, interviewed about their sleep habits and work performance. Some of the results of the pilot survey are:

  • 23% admitted sleepiness has affected their job performance at least once a week
  • 20% said sleepiness had caused safety problems on the job
  • 37% of pilots reported that their current work schedule did not allow adequate time for sleep
  • 50% said they rarely or never got a good night’s sleep on work nights

Fatigue was identified as probable cause, contributing factor, or a finding in 20% of 182 major NTSB investigations completed between 1 January 2001 and 31 December 2012, ranging from 40% of highway investigations to 4% of marine investigations.

Human fatigue can have a role in accidents causation by producing performance impairment when the individual is awake, or by inducing microsleeps or producing an uncontrolled and unintentional full sleep episode.



Fatigue refers to a physiological state of reduced mental or physical performance capability in which there is a decreased capacity to perform cognitive tasks and an increased variability in performance. It is an enabler of poor judgment and decision-making, slowed reaction times, and loss of situational awareness and control. It degrades a person’s ability to stay awake, alert, and attentive to the demands of controlling a vehicle safely.


Fatigue increases the desire to obtain sleep. It is also associated with tiredness, weakness, lack of energy, lethargy, depression and lack of motivation. To make matters worse, fatigue actually impairs the ability to self-judge just how fatigued the person is.

Fatigue results from an imbalance between:

  • The physical and mental exertion of all waking activities (not only duty demands); and
  • Recovery from that exertion, which, except for recovery from muscle fatigue, requires sleep.

It is associated with sleep loss, extended wakefulness, high mental and/or physical workload, long unbroken periods of work -known as ‘time-on-task’ fatigue-, and circadian phase. In addition, there are acute influences such as monotony, boredom and environmental factors at the workplace (i.e. at the airport during long breaks or on the flight deck) that can interact with the factors cited above to precipitate the apparition of fatigue.

Sleep loss and extended wakefulness

Several factors are involved in the development of a loss of sleep and fatigue in aviation: less-than-optimal sleeping conditions, early reporting time, rotating and non-standard work shifts, night duty, the time on duty, long spans of wakefulness during the working day, the number of sectors, the number of time- zones crossed and the number of consecutive flying days.

There are other factors, like stress, disease, noise, vibrations/movement, or an upright sleep posture that can also influence sleep quantity and quality. Indeed, it should be emphasized that 8 hours of sleep may fail to provide restitution if it is highly fragmented as a result of these or other disturbing factors. This is particularly likely to be the case with sleep taken during the day when a range of environmental factors often contributes to sleep disturbance.

The main cause of problems associated with the unusual rest and activity patterns experienced by aircrew is the conflict with the biological clock which synchronizes our activity with that of the environment. This clock guides the circadian rhythm by activating the body, through increased metabolism during the day, and reduced levels at night, to promote recuperation. The result is an increased alertness during the day and lowered wakefulness and functional capability at night, being the lowest point of performance at around 05:00h (Window Of Circadian Low-WOCL). The reduction in performance at the lowest point during WOCL is severe and will markedly impair various aspects of performance including attention, reaction time and co-ordination. Humans simply are not designed to operate under the pressured 24/7 schedules that often define aviation operations, whether the operations are short-haul commercial flights, long-range transoceanic operations, or around-the-clock and shift work operations.


Because performance and alertness levels are largely influenced by the complex interaction between sleep and the 24-hour biological clock, the cited factors determine in a predictable way the background level of fatigue/alertness at any given moment.

The various factors that contribute to fatigue are individually capable of causing dangerous impairments in performance. Using a standardized performance test in, both, sleep loss and alcohol consumption conditions, investigators could provide a blood alcohol concentration metric to compare results from the sleep loss condition. Results demonstrated that after 17 hours of continuous wakefulness, cognitive psychomotor performance decreased to a level equivalent to a blood alcohol concentration of 0.05%. After 24 hours of continuous wakefulness, performance was approximately equal to a blood alcohol concentration of 0.10%.(Dawson D and Reid K. Fatigue, alcohol and performance impairment. Nature, 388:235, 1997.)

There is a discernible pattern of increased probability of an accident as duty time increases for commercial aircraft pilots. For 10-12 hours of duty time, the proportion of accident pilots with this length of duty period is 1.7 times as large as for all pilots. For pilots with 13 or more hours of duty, the proportion of accident pilot duty periods is over five and a half times as high. 20% of human factor accidents occurred to pilots who had been on duty for 10 or more hours, but only 10% of pilot duty hours occurred beyond the 10th duty hour. Similarly, 5% of human factor accidents occurred to pilots who had been on duty for 13 or more hours, where only 1% of pilot duty hours occur beyond the 13th duty hour. The greater the hours of duty time for pilots the greater probability of an accident.

The ability of aircrew to sustain levels of alertness during long flight duty periods has been the subject of many scientific investigations. There is an interaction between time of day, or circadian factors, on the one hand, and time since sleep and time on task on the other, with the result that duties at certain times of day are particularly susceptible to the effects of fatigue:

1. Night duty (flights ending during / extending through the Window of Circadian Low- WOCL): Night duty hours are especially vulnerable to severe fatigue. The longer the duty period extends the greater the pressure for sleep becomes, and there is strong evidence to show that many crews fall asleep, either voluntarily or involuntarily, on the flight deck. The longer the flight, the greater the risk that both pilots will fall asleep at the same time. Their ability to respond to an emergency situation, or to land the plane in adverse conditions, may also be severely impaired.

2. Duty during day time – early departures: Whereas long duty hours can be sustained during many day-time flights, specific problems are associated with early starts. Early start times are inevitably associated with a loss of sleep, the result of which is lower levels of alertness throughout the entire duty period. The effect is exacerbated over several successive early starts, due to an accumulating sleep deficit.

However, the most serious problems arise when the factor combine to provide even larger impairments. Night duty will involve work at the circadian low and an extended time awake. The two together will cause psychomotor impairment similar to that which is seen after the ingestion of enough alcohol to generate a blood alcohol level of 0.08% (which is significantly beyond the drink-drive limit in most European countries).

If the lack of sleep extends into the next day (comparable to the late morning after a 6-hour time-zone crossing without any post-flight sleep), there is a large impact on memory processes – with an impairment in the ability to respond to changed circumstances. The effects are further exacerbated in the event that prior sleep (i.e. before the flight/night duty) has also been disturbed.

Moreover, sleep taken after night duty will be truncated by 1-2 hours, because the circadian rise of metabolism in the morning will interfere with the sleep process. Sleep during the day on layover (before commencing another flight duty) is shallow, disrupted and shorter than during the WOCL. This has a detrimental effect on alertness during the subsequent flight duty.

Time-zone transitions

Flights across 4 or more time zones lead to the disturbance of sleep and circadian rhythms. If in addition, the flight is performed at night it magnifies performance decrements and increases the desire to sleep. As a result of these disturbances, more time is required to recuperate, both during layover and after return to base, before further flying duty is undertaken.

Night flights from west to east (North America to Europe – Europe to Asia) have an inherent augmented risk of fatigue. To counter fatigue, some pilots will try to nap before a night–time leg. While this can be helpful in some cases, it cannot prevent fatigue in all pilots. Moreover, it is not always possible to obtain an adequate amount of good quality sleep during the day and performance decrements will persist.

In addition, these types of flights are characterized by long periods of darkness with few operational demands while on cruise altitude, creating inherently soporific conditions. It is not until the flight approaches dawn that pilots experience reduced sleepiness as the daylight and circadian rhythms start to alleviate some of the fatigue. Nonetheless, the high workload requirements of approach and landing have to be borne at a time when there is a significant risk of pilot fatigue.

Most of these pilots fly a small number of night-time legs per month and revert to sleeping at night when not working. The circadian system of pilots who fly only a small number of night–time legs will not adapt to working at night, and these pilots are likely to display performance decrements during the night–time leg in spite of any countermeasures.

 Quality of In-Flight Sleep

Crewmembers’ sleep in onboard crew rest facilities is lighter and more fragmented than sleep on the ground. Sleep during flight deck naps is also lighter and more fragmented than would be predicted from laboratory studies.


Sleep debt

A sleep deficit of more than 2 hours has a discernible effect on performance capability. An acute reduction of sleep to below 6 hours will cause increased fatigue and reduced performance in most individuals. Sleep loss will also accumulate across time: 5 hours of sleep per day will be equivalent, in terms of fatigue and performance, to one full night of sleep loss after 5 days.

The effects of restricting sleep night after night accumulate so that people become progressively less alert and less functional day after day. This is sometimes described as accumulating a sleep debt. This is a common occurrence for crewmembers when minimum rest periods are scheduled for several days in a row.

The shorter the time allowed for sleep each night, the faster alertness and performance decline. Spending 7 hours in bed for 7 consecutive nights is not enough to prevent a progressive slowing down in reaction time. The decline is more rapid if spent only 5 hours in bed each night, and even more rapid for those who spent only 3 hours in bed each night. This is described as a dose-dependent effect of sleep restriction.

The pressure for sleep increases progressively across successive days of sleep restriction. Eventually, it becomes overwhelming and people begin falling asleep uncontrollably for brief periods, known as micro-sleeps. During a micro-sleep, the brain disengages from the environment (it stops processing visual information and sounds.

Full recovery of waking function after sleep restriction can take longer than two nights of recovery sleep (i.e., longer than it takes the non-REM/REM cycle to recover). Indeed, chronic sleep restriction may have effects on the brain that can affect alertness and performance days to weeks later.

For the first few days of severe sleep restriction (for example, 3 hours in bed), people are aware that they are getting progressively sleepier. However, after several days they no longer notice any difference in themselves, even although their alertness and performance continues to decline. In other words, as sleep restriction continues, people become increasingly unreliable at assessing their own functional status. This finding raises a question about the reliability of subjective ratings of fatigue and sleepiness as measures of a crewmember’s level of fatigue-related impairment

The sleep-restricted brain can stabilize at a lower level of functioning for long periods of time (days to weeks).


Recovery from sleep loss

Lost sleep is not recovered hour-for-hour, therefore, recovery sleep should be longer than usual. The restorative value of sleep quality (sleep quality) depends on going through unbroken non-REM/REM cycles, which suggests that both types of sleep are necessary and one is not more important than the other.

The more the non-REM/REM cycle is fragmented by waking up, or by arousals that move the brain to a lighter stage of sleep without actually waking up, the less restorative value sleep has in terms of how a person feel and function the next day.

Once out of duty and given the opportunity to sleep at leisure, on the first recovery night, there is more slow-wave sleep than usual. Indeed, there can be so much slow-wave sleep that there is not enough time to make up REM sleep. On the second recovery night, there is often more REM sleep than usual. Only by the third recovery night, the non-REM/REM cycle is usually back to normal.

To reduce crewmember fatigue requires reducing the exertion of waking activities and/or improving sleep.


Managing fatigue is a very complex task that must go far beyond flight/duty/rest time limitations. All the cited factors preclude a simple solution. There is no a simple and unique one-size-fits-all approach strategy that works for everybody.

A variety of regulatory actions to address fatigue-related safety risks has been implemented, reviewed and revised. A lot of information has been published, multiple training courses and strategies have been designed. However, fatigue continues to cause and contribute to transportation safety events.

Sometimes, because of global and national economic issues, civil aviation authorities may be compelled by commercial pressures to ease their national regulations with respect to the provisions of regulations of other nations. Loopholes could be exploited by the industry, within the different regulations, to promote their economic benefit.

Regulators must be aware that flight/duty/rest regulatory schemes loopholes when taken together, and applied in an environment of increasing competition, may encourage, or indeed compel, individual airlines to operate everywhere close to the defined limits by business considerations. In that case, it is likely that this would lead to a significant reduction in the safety of airline operations. There would be a clear competitive advantage for those airlines that operate as close as possible to the limits specified in the regulations, but there would be a significant increase in the risk of fatigue-related incidents and accidents if operators were permitted to operate to the limits.

The complexity and diversity of operational requirements demand a variety of approaches. Concept development should be initiated to move beyond current flight/duty/rest regulatory schemes and toward operational models that provide flexibility and maintain the safety margin.

Scientific evidence has remarked the vital importance of adequate sleep, not just rest, for restoring and maintaining all aspects of waking function and the importance of daily rhythms in the ability to perform mental and physical work, and in sleep propensity (the ability to fall asleep and stay asleep). Therefore it is critical that the core human requirement for sleep be managed effectively and operations should reflect the fact that the basic properties of the circadian clock directly affect an operator’s performance, productivity, and safety.

Some Mitigation Strategies that could be taken into account are:

  • Proper work/rest scheduling is of primary importance
  • Duty periods should not be as long as 12 hours when they surpass the window of circadian low- WOCL
  • If there is early starts the flight duty periods should be shorter than the allowed by the regulations
  • There shouldn’t be more than 2 consecutive night duties
  • There shouldn’t be more than 2 consecutive early starts
  • Strategic napping and strategic use of caffeine as alertness-enhancing compound must be considered
  • There is good evidence that in-flight sleep improves subsequent alertness and reaction speed and is a valuable mitigation strategy. The 40 minutes planned rest period provide time for preparation for the rest period, falling asleep, and sufficient length time for an approximately 26 to 30 minutes nap to occur. After the nap, a recovery period of 15-20 minutes allows time for sleep inertia to dissipate if present and to brief the rested pilot before reentering the operational loop. The amount of sleep obtained in cockpit nap does not affect subsequent layover sleep or circadian rest/activities patterns.
  • Rest is not the same as sleep. A rest period with reduced physical or mental activity does not produce the same effects of sleep. Only sleep can reverse the physiological sleepiness.
  • Layover rest periods should provide sufficient time to recover from the immediate effects of the previous flight and to obtain sufficient sleep prior to the next report
  • A sleep opportunity of 8 hours may not be sufficient after a night flight or a flight with a large (= 4 hours) time difference. Thus, even a minimum rest period of 10 hours in many cases may not provide sufficient time for recovery.
  • Schedules must be designed to allow periodic opportunities for recovery and periodically include an opportunity for at least two consecutive nights of unrestricted sleep, to enable crewmembers to recover from the effects of sleep loss. This does not equate to 48 hours off. For example, 48 hours off duty starting at 02:00 would only give most people the opportunity for one full night of unrestricted sleep. On the other hand, 40 hours off starting at 21:00 would give most people the opportunity for two full nights of unrestricted sleep.
  • Additional nights may be needed for recovery if a crewmembers’ circadian body clock is not already adapted to the local time zone.
  • Recovery opportunities (sleep opportunities) need to occur more frequently when daily sleep restriction is greater, because of the more rapid accumulation of fatigue.
  • Rest periods should include defined blocks of time (sleep opportunities) during which crewmembers are not contacted except in emergencies. These protected sleep opportunities need to be known to flight crews and all other relevant personnel. For example, calls from crew scheduling should not occur during a rest period as they can be extremely disruptive.
  • Operators should also develop procedures to protect crewmember sleep at layover and napping facilities. if a rest period occurs during the day at a layover hotel, the operator could make arrangements with the hotel to restrict access to the section of the hotel where crewmembers are trying to sleep (such as no children, crewmembers only) and instruct their staff to honor the necessary quiet periods (for example, no maintenance work or routine cleaning)
  • There are computer models that incorporate the schedule information and provide an instant evaluation of alertness levels on any given roster. It is possible to compare the effects on fatigue of different rosters and to estimate the effects of modifying the pattern of duty in different ways as well as estimate the probability that either a single pilot or both pilots will be asleep on the flight deck at any particular time
  • Good sleep hygiene by flight crew is essential. Therefore, pilots and other aviation personnel, particularly those performing overnight operations especially during the window of circadian low, must be deeply and recurrently trained about the physiology of sleep and circadian rhythm. The training should include the causes, effects and risks associated with fatigue as well as it’s prevention and mitigation strategies. Personal responsibility during non-work periods, rest environments, and the effects of commuting and/or napping should be stressed too. The fatigue training should include personnel involved in crew scheduling and senior management too.

Managing fatigue must take into account operational differences and differences among crew members and requires a comprehensive approach that focuses on research, education and training, technologies, treatment of sleep disorders, hours-of-service regulations, and on- and off-duty scheduling policies and practices.

Ultimately, fatigue-related accidents can be avoided with a combination of science-based regulations, comprehensive fatigue risk management programs, and individual responsibility.

To be continued…


  1. Paper prepared for the European Transportation Safety Council “Meeting to discuss the role of EU FTL legislation in reducing cumulative fatigue in civil aviation” in Brussels on Wednesday 19th February 2003. Akerstedt, R. Mollard, A. Samel, M. Simons, M. Spencer. European Committee for Aircrew Scheduling and Safety.
  2. Fatigue in transportation: NTSB investigations and safety recommendations. Jeffrey H Marcus, Mark R Rosekind. Marcus JH, Rosekind MR. Inj Prev Published Online First: February 29, 2016. doi:10.1136/injuryprev-2015-041791
  3. Prevalence of fatigue among commercial pilots. Jackson CA1, Earl L. Occupational Medicine (Lond). 2006 Jun;56(4):263-8 https://www.ncbi.nlm.nih.gov/pubmed/16733255
  4. Barometer on pilot fatigue European Cockpit Association. 2012
  6. Are pilots at risk of accidents due to fatigue?. Goode, J. H. Federal Aviation Administration, Office of Aviation Policy and Plans, Washington, DC 20591, USA, March 2003
  7. Pitch Excursion Air Canada Boeing 767–333, C–GHLQ North Atlantic Ocean, 55°00’N029°00’W 14 January 2011. Transportation Safety Board of Canada (TSB)
  9. FAA Advisory Circular AC No: 120-100. Subject: Basics of Aviation Fatigue. Federal Aviation Administration, June 7th, 2010.
  10. Crew factors in flight operations IX: Effects of planned cockpit rest on crew performance and alertness in long-haul operations. Rosekind, Mark R, Graeber, R. Curtis, Dinges, David F., Connell, Linda J., Rountree, Michael S, Spinweber, Cheryl L, Gillen, Kelly A
    Mark R. Rosekind, Ph.D.1, LCDR David F. Neri, Ph.D. 1,2, and David F. Dinges, Ph.D. 3
    1NASA Ames Research Center, 2United States Navy Medical Service Corps, 3University of Pennsylvania School of Medicine.
  12. NTSB Most wanted list 2017. Reduce Fatigue-Related Accidents. National Transportation Safety Board, January 2017.


  1.  Stress and lack of quality sleep, factors leading to serious incident
  2. Pilots fatigue lead to a Danish Air Transport ATR 72 serious incident


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

CRM at its best: Qantas flight 32, learning from the recent past

“Let’s look at what’s working. If all we could do is build ourselves a Cessna aircraft out of the rubble that remained, we would be happy.”

qantas-1Photo:  ATSB Aviation Occurrence Investigation AO-2010-089 Final Report

In homage to an outstanding performance of an A380 flight crew facing a catastrophic failure of an inboard engine following an uncontained explosion on the morning of November 4th, 2010.


The aircraft departed Changi Airport, Singapore on a scheduled passenger flight to Sydney, Australia. About 4 minutes after take-off, while the aircraft was climbing through about 7,000 ft, the flight crew heard two ‘bangs’ and a number of warnings and cautions were displayed on the electronic centralised aircraft monitor (ECAM).

Initially, the ECAM displayed a message warning of turbine overheat in the No. 2 (inner left) engine. That warning was followed soon after by a multitude of other messages relating to a number of aircraft system problems. After assessing the situation and completing a number of initial response actions, the flight crew was cleared by ATC to conduct a holding pattern to the east of Changi Airport. While in the holding pattern, the flight crew worked through the procedures relevant to the messages displayed by the ECAM. During that time the flight crew was assisted by an additional crew that were on the flight deck as part of a check and training exercise. The aircraft sustained significant impact damage from a large number of disc fragments and associated debris. The damage affected the aircraft’s structure and a number of its systems.

A large fragment of the turbine disc penetrated the left wing leading edge before passing through the front spar into the left inner fuel tank and exiting through the top skin of the wing. The fragment initiated a short duration low-intensity flash fire inside the wing fuel tank.

Another fire has occurred within the lower cowl of the No. 2 engine as a result of oil leaking into the cowl from the damaged oil supply pipe. The fire lasted for a short time and self-extinguished.

The large fragment of the turbine disc also severed wiring looms inside the wing leading edge that connected to a number of systems.

A separate disc fragment severed a wiring loom located between the lower centre fuselage and body fairing. That loom included wires that provided redundancy (back –up) for some of the systems already affected by the severing of wires in the wing leading edge. This additional damage rendered some of those systems inoperative.

The aircraft’s hydraulic and electrical distribution systems were also damaged, which affected other systems not directly impacted by the engine failure. (Excerpted from In-flight Uncontained Engine Failure. Airbus A380-842, VH-OQA. Australian Transportation Safety Board Transport Safety Report Executive Summary)

We, aviation professionals and aviation safety scholars, sometimes tend to focus, perhaps too much, in aviation accidents and incidents. They are a great source of knowledge and learning that we later try to convert in accident prevention strategies. The human limitations, the error and its multiple causes and sometimes terrible consequences have a charming effect on us.

This time I want to do something different. This time I want to highlight the positive aspects of human performance: those unique things human beings do well, presented to us as outstanding airmanship, leadership and teamwork. All my respect to those five pilots, impeccably led by Captain Richard de Crespigny.

Next, I share the article published in AeroSafety World, with Captain de Crespigny’s first-hand testimony. All credit to the author and the publisher. The photos were added by me:


Singapore — First, came the matter of determining how much of the Airbus A380 was still functioning. Then the issue was maintaining control of the crippled aircraft flying on the edge of a stall during approach with marginal aileron control effectiveness. Finally, there was the problem of sitting over a rapidly spreading pool of jet fuel in an aircraft with white-hot brakes and an engine that refused to shut down.

The uncontained engine failure on a Qantas A380 on Nov. 4, 2010, did not precipitate a catastrophic accident, and 469 people returned safely to the ground at Singapore, said the Qantas Flight 32 captain, Richard de Crespigny, because five experienced pilots in the cockpit — three in the regular crew and two check captains — worked as a unified team with cool heads and a singleness of purpose.

In his keynote speech opening Flight Safety Foundation’s 64th International Air Safety Seminar in Singapore in November 2011, and in an extensive interview with AeroSafety World, de Crespigny detailed the accident. What follows are just a few of the significant details of this incredibly complicated situation.

The triggering failure that launched the drama was the uncontained failure while climbing through 7,000 ft, of the airplane’s no. 2 Rolls-Royce Trent 972 three-spool turbofan, perceived in the cockpit as “two bangs, not terribly loud,” de Crespigny said. The aircraft damage caused by the heavy, high-speed engine parts leaving the nacelle created what he called “a black swan event, unforeseen, with massive consequences.qantas-2qantas-6qantas-adicional

Photos:  ATSB Aviation Occurrence Investigation AO-2010-089 Final Report

“What did we know? We knew that engine no. 2 had failed, there was a hole in the wing, fuel was leaking from the wing and we had unending checklists. What we didn’t know is that no. 2 had had a failure of the intermediate pressure turbine, engine no. 1 had also been damaged, we had 100 impacts on the leading edge, 200 impacts on the fuselage, impacts up to the tail and seven penetrations of the wing, going right through the wing and up through the top. We had lost 750 wires…. We lost 70 systems, spoilers, brakes, flight controls. … Every system in the aircraft was affected.

“Flight controls were also severely damaged. It wasn’t just the slats; we [lost] a lot of our ailerons … lost 65 percent of our roll control,” de Crespigny said. The situation was made worse, he said, because, with fuel flowing out of the left wing, the aircraft was laterally unbalanced.

“We were getting pretty close to a [cockpit work] overload situation,” working through the checklists, cancelling the alarms. “It was hard to work out a list of what had failed. It was getting [to be] too much to follow. So we inverted our logic. Like Apollo 13, instead of worrying about what failed, I said, ‘Let’s look at what’s working.’ If all we could do is build ourselves a Cessna aircraft out of the rubble that remained, we would be happy.”

Wanting to be well prepared and drop as much fuel as possible before making what would still be an overweight landing, de Crespigny entered a holding pattern. “We had seven fuel leaks coming out of multiple parts of the wing. At 50 tonnes overweight, and no [working] fuel jettisoning system, this was our jettisoning system.”

Fortunate to have the longest runway in Southeast Asia available to them, the crew still had slim margins. Taking into account the known problems — including no slats and no drooping ailerons on final — the crew computed that the aircraft could be stopped 100 m (328 ft) before the runway end.

“We briefed the approach, and then — one of the more emotional events of the crisis — we did … three control checks. We proved the aircraft safe for landing in a landing configuration. We did a rehearsal for the landing with the gear down,” using gravity to drop the gear, he said, “flaps out and at approach speed, and the aircraft proved out.”

Knowing that the fly-by-wire stick would mask the aileron movement needed to maintain attitude, de Crespigny “went to the control page to look at the percentage of effort of the flight controls we had remaining. We had normal flight controls except for the ailerons, and there we’d lost 65 percent of our roll control, lost both outer ailerons, lost one of the mids, and we were left with … one mid and the high-speed ailerons, small and inboard.

“But we also had imbalances” due to fuel issues, he said. “I was very concerned about controllability. So we did the control check, and as I rolled the aircraft up to about 10 degrees of bank, we looked at the flight controls [ECAM page] and it looked like we were using like 60 to 70 percent of the remaining ailerons just to do a very gentle turn.

“I could easily reach maximum deflection of the ailerons, and when you reach that point, the spoilers come up next. You keep getting roll control by dumping more lift, increasing your stall speed. I was really worried, [knowing I had] to be so careful to not get the spoilers coming up. I had to keep the heading and yaw as accurate as possible, so I decided to use the automatic pilot for the approach — its accelerometers sense small changes and put in tiny corrections earlier than I will.”

qantas-3qantas-4qantas-5Photos: ATSB Aviation Occurrence Investigation AO-2010-089 Final Report

Manual thrust control can allow for unbalanced thrust, which would induce destabilizing yaw. “We had a long approach, so to get stable thrust I exactly matched [engines] one and four and locked them down, and used engine three to adjust the approach speed, using that [engine] because it is inboard and produces less yaw. So I had accurate heading control, controls were not used very much, and with only one engine used to fine tune the speed, [we maintained] minus 2 kt to plus 3 kt for the whole approach.”

Another pilot in the cockpit warned, “‘Richard, you can’t be fast.’ During approach, our air speed margin was very small. Put in 3 kt, we run off the end of the runway.”

As it turned out, he couldn’t be slow, either. “I slowed down 1 kt and we got a speed warning,” he said. “That was unexpected, absolutely. We clearly didn’t have a 17 to 18 percent stall margin. We had two speed warnings” during the approach, and “in the flare, we got a stall warning.”
“We landed 40 tonnes overweight, a relatively good landing. When we stopped, the brakes said 900 degrees C (1,650 degrees F), but it takes five minutes for heat to get to the sensor, so 900 degrees on stopping meant that those brakes were going to go well beyond 2,000 degrees C.”

However, on landing “fuel sloshed to the front” and began gushing out of the holes in the wing leading edge. “The auto-ignition point of kerosene is 220 degrees C, so we were concerned.” Happily, the Singapore crash rescue crew’s response was superb, de Crespigny said. “Firemen came in and put foam down over the fuel, over the brakes, and the temps started going down.”

Finally, though, the engine no. 1 refused to shut down, further delaying evacuation. But with the threat of fire mitigated, the aircraft was evacuated before the engine was killed with massive amounts of fire-fighting foam.


Photo: ATSB Aviation Occurrence Investigation AO-2010-089 Final Report


  1. In-flight Uncontained Engine Failure. Airbus A380-842, VH-OQA. Australian Transportation Safety Board. ATSB Transport Safety Report.  Aviation Occurrence Investigation AO-2010-089. Final Report 
  2. A Black Swan Event. Saving a crippled A380. DonoghueJ.A. AeroSafety World December 2011/January 2012
  3. Interview with Capt. Richard de Crespigny – Part 1
  4. Interview with Capt. Richard de Crespigny – Part 2


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