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 


LaMía CP2933 accident in Colombia, preliminary report



Aircraft: AVRO 146-RJ85

Date and time: 29 November 2016, 02:58UTC (All times in this report are UTC. Five (5) hours should be subtracted to obtain the legal time in Colombia)

Location: “Cerro Gordo”, Municipality of La Unión Antioquia – Colombia.

Coordinates: N05°58’43.56″ – W075°25’7.86″

Type of operation: Commercial Air Transport (Passengers) Charter Flight


Persons on board: 04 Crew, 73 Passengers


Background to the flight

The operator had been chartered to fly the Chapecoense football team and associated personnel from São Paulo, Brazil (Guarhulos SKGR airport) to Rionegro, Colombia (Jose Maria Cordoba Airport in Rionegro, near Medellin). Under Brazilian regulations, charter flights may only normally be operated by an operator based in either the country of departure or arrival. The operator was based in Bolivia and was unable to get the necessary permission to operate the flight as planned. Arrangements were made instead for the passengers to be flown from São Paulo – Brazil (ICAO: SBGR) on a scheduled flight to Santa Cruz – Bolivia (ICAO: SLVR) where they boarded the charter flight to Rionegro – Colombia (ICAO: SKRG).

History of flight

The history of the flight has been compiled from a number of sources, including preliminary information from the flight data recorder (FDR), cockpit voice recorder (CVR) and recorded ATC and radar data. The ATC transcript is a translation of the original transmissions which were in Spanish.

On 28 November 2016, the aircraft departed the operator’s maintenance base at Cochabamba (OACI: SLCB), Bolivia, at 17:19hrs and positioned to Viru Viru International Airport (OACI: SLVR), Santa Cruz in Bolivia, landing at 17:58hrs.

After the arrival of the aircraft at Santa Cruz, it was refueled, with witness information indicating that the commander had instructed the maximum fuel load of 9,300 kg to be used.

It was reported that some of the crew had thought the aircraft would be refueling enroute at Cobija Airport (OACI: SLCO). Cobija Airport is located close to the border between Bolivia and Brazil and normally only operates during daylight hours. On 28 November 2016, it closed at 22:43hrs.

After the passengers had all arrived at Santa Cruz they boarded the aircraft and at 22:08hrs engine start commenced. On board were the operating crew; comprising a commander, co-pilot and two cabin crew members; and 73 passengers; including an engineer and dispatcher from the operator, and a private pilot who occupied the flight deck jump seat.

The aircraft took off at 22:18hrs and climbed to an initial cruising flight level of FL260, levelling at 22:41hrs. It then climbed again at 22:49hrs to FL280, levelling at 22:58hrs. It then started climbing to its final cruising level of FL300 at 23:54hrs, levelling at 00:14hrs. The cruising speed was recorded as 220 kt CAS. The route flown is shown in Figure 1.


During the cruise, the CVR recorded various crew conversations about the fuel state of the aircraft and they could be heard carrying out fuel calculations. At 00:42:18hrs one of the pilots could be heard to say that they would divert to Bogota (ICAO: SKBO) to refuel but at 00:52:24hrs a further conversation took place, shortly after the aircraft was transferred to Colombian ATC, with the crew deciding to continue to Rionegro (ICAO: SKRG). At 01:03:01hrs the crew began their brief for the approach to Jose Maria Cordoba Airport, Rionegro.

At 01:15:03hrs the CVR ceased recording.

The aircraft commenced decent at 02:30:30hrs at which time it was about 75NM to the south of Rionegro. It levelled at FL250 at 02:36:40hrs and at 02:40hrs ATC transferred the crew to Medellin Approach at 02:40hrs who instructed them to descend to FL230 and to hold at Rio Negro VOR (VOR RNG).

At 02:42:12hrs the crew was instructed to continue descent to FL210. At 02:43:09hrs the crew asked to hold at GEMLI RNAV Point (Figure 2), which was approved. It overflew GEMLI at 02:43:39hrs and entered the hold. (Figure 3 – each complete hold has a ground track of approximately 24 nm).

At this time there were three other aircraft holding at the Rio Negro VOR, at FL190, 18,000ft and 17,000ft. There was also an aircraft diverting into Rionegro with a reported fuel leak, about to commence its final approach to Runway 01 at Rionegro (SKRG).



At 02:43:52hrs the aircraft was levelled off at FL210, the flaps lowered to FLAP18 and the speed reduced to 180 kt CAS. At 02:45:03hrs the crew informed ATC that they had entered the hold at GEMLI at FL210.

The subsequent radio communications between the crew (callsign LMI 2933) and ATC have been tabulated below.


ATC then cleared LAN3020, the aircraft holding at 17,000ft for the approach.


ATC then cancelled the approach clearance for LAN 3020


At 02:53:07 hrs the thrust levers were reduced and the aircraft commenced a descent.

At 02:53:09 hrs the airbrake was extended


At 02:53:24 hrs the gear was selected down.


At 02:53:36 hrs FLAPS24 were selected and the aircraft speed began to reduce and continued to do so until the end of the FDR recording.

At 02:53:45hrs the Number 3 engine speed no longer matched the thrust lever demand and began to run down. 13 seconds later the same occurred on the Number 4 engine.


At 02:54:36hrs the FDR recorded FLAPS33 selected.

At 02:54:47 hrs the Number 3 and Number 4 engine low oil pressure states were recorded on the FDR together with a MASTER WARNING. At the same time, over a 12 second period, the Number 1 engine N1 reduced from 39.5% to 29.0% and recovered (N1 value indicates the rotation speed of the 1st (compression) stage of a turbojet engine).

At 02:55:04hrs the Number 2 engine speed no longer matched the thrust lever demand and began to run down.


At 02:55:19hrs, over a period of 10 seconds, the Number 1 engine N1 reduced again, from 38.1% to 29.9%, and recovered.

At 02:55:27hrs the Number 2 engine low oil pressure state and a MASTER WARNING were recorded on the FDR.


At 02:55:41hrs the Number 1 engine began to run down Following the loss of all engines, at 02:55:48hrs the FDR ceased recording. At this time the FDR data showed that the aircraft was at a CAS of 115 kt, a ground speed of 142 kt and a pressure altitude of 15,934 ft msl.

The aircraft was 15.5 nm to the south of the threshold of Rionegro Runway 01 and 5.4 nm south of the accident site (which was at an elevation of about 8,500 ft amsl).

Radar recording report indicates Mode C lost at 02:55:52hrs at which time there was only a primary radar contact for the aircraft.


No further response was received from LMI 2933 despite repeated calls by ATC.

Organization of Investigation

At 03:10hrs, the Grupo de Investigación de Accidentes Aéreos (GRIAA) from the Civil Aviation Authority of Colombia was alerted of the disappearance and subsequent location of the aircraft AVRO RJ85 accident in “Cerro Gordo”, Municipality of La Unión – Antioquia.

Immediately in accordance with the provisions of Colombian Aeronautical Regulations – RAC 8, a safety investigation was immediately initiated by GRIAA.

A team of 8 investigators traveled to the accident site on the morning of 29 November 2016, arriving at 11:30hrs. The access to the crash site was done by land and air.

Flight Recorders (FDR, CVR) were found on 29, November 2016 at 17:09hrs and placed in custody of GRIAA investigators for further preparation for readout.

Following the International Civil Aviation Organization (ICAO) Annex 13 provisions, the GRIAA made the formal Notification of the Accident to:

– International Civil Aviation Organization – OACI

– The Dirección General de Aeronáutica Civil – AIG (Bolivia), as State of Registration of the aircraft.

– The Air Accident Investigation Branch – AAIB (United Kingdom), as State of Manufacture of the aircraft. This allowed the assistance of technical advisors of the aircraft manufacturer.

– The National Transportation Safety Board – NTSB (United States), as State of Engine Manufacturer. This allowed the assistance of technical advisors of the engine manufacturer.

– The Centro de Investigação e Prevenção de Acidentes Aeronáuticos – CENIPA (Brazil), As State of the Nationals involved in the accident.

The Investigation was organized in different working groups in the areas of Airworthiness, Power Plants, Flight Operations, Human Factors, Survival and Air Traffic. The Accredited Representatives and Technical Advisors were divided into the formed working groups.

This preliminary report contains facts which have been determined up to the time of issue.

This information is published to inform the aviation industry and the public of the general circumstances of the accident and should be regarded as tentative and subject to alteration if additional evidence becomes available.

Injuries to persons


 Damage to the aircraft


Other Damage

Damage to surrounding vegetation.

Personnel Information

  1. Captain

Age: 36

Licence: Airline Transport Pilot – ATP

Nationality: Bolivian

Medical Certificate: 1st. Class

Last proeficience check: 03, July 2016

Total flying hours: 6,692.51 (Ref: LAMIA status documents 20 Nov 2016)

Total RJ85 flying hours: 3,417.41 (Ref: LAMIA status documents 20 Nov 2016

2. Co-pilot

Age: 47

Licence: Airline Transport Pilot – ATP

Nationality: Bolivian

Medical Certificate: 1st. Class

Last proeficience check: 03, July 2016

Total flying hours: 6,923.32 (Ref: LAMIA status documents 20 Nov 2016

Total RJ85 flying hours: 1,474.29 (Ref: LAMIA status documents 20 Nov 2016)

Flight Recorders

The aircraft was fitted with a CVR and FDR, both of which were powered by the aircraft’s AC Essential electrical bus which required one or more of the engines or the APU to be running. Both recorders were recovered to the Air Accidents Investigation Branch (AAIB) in the UK for download.

1 Flight data recorder

The FDR download revealed approximately 54 hours of operation which included the accident flight. A number of flight parameters were recorded including flight control positions, autopilot and autothrust modes, aircraft position, engine fan speed (N1) and thrust lever position. Fuel flow was recorded for each engine every 64 seconds. APU operation, fuel quantity, fuel and master cautions were not recorded.

2 Cockpit voice recorder

The CVR was successfully downloaded and recorded just over two hours of operation.

Using the recorded UTC timings from radio transmissions and the FDR, the CVR was timealigned and revealed a recording start time of 23:08:33hrs on 28 November 2016. The following two hours of recording was of the accident flight. The recording then ceased at 01:15:0hrs at which time the aircraft was about 550 nm from Rionegro and was one hour,40 minutes and 45 seconds prior to the end of the FDR recording.

There was no recorded discussion about the CVR and the reason for the CVR recording ceasing early is unknown at this stage in the investigation.

Wreckage and impact information

The crash site was known as “Cerro Gordo”, which belonged to the Municipality of La Unión in the Department of Antioquia – Colombia. The wreckage were disturbed during search and rescue operations following the accident. Access to the crash site was limited several days and lifting equipment was not available.

1 Initial impact site

The initial point of impact was identified on the south face at the hill just below the hill ridge on an approximately 310° compass heading. According to the GPS readings, an energy path extended from the IPI approximately 140 meters down the north hill face to the main wreckage location, on an approximate 290° compass heading.

The approximate GPS position of the initial impact site was N05°58’43.56″ – W075°25’7.86″. The largest item was the tail unit, complete with rudder and both elevators (Figure 4 and 5). The tail unit had detached from the main fuselage at the pressure bulkhead frame. The leading edges of the horizontal stabilizers and fin were in good condition with little evidence of damage. The airbrakes were close to the tail unit and remained attached to it by electrical wiring.



Components from the hydraulic bay and Environmental Control System (ECS) bay were identified at the initial impact site. These included hydraulic reservoirs and a heat exchanger from the air conditioning packs.

The stick push reservoir was identified at the site. The reservoir is installed in the upper section of the avionics bay, beneath the cockpit floor.

Other noteworthy items identified at the initial site included a main landing gear door, a section of inboard engine accessory gearbox (complete with starter motor), an engine hydro-mechanical unit, the rear section of the outboard fairing from the right wing and a passenger seat cover.

2 Engines

The Number 1 and Number 4 engines were found in the proximity to the initial impact point, with Number 1 engine to the left of the impact site and Number 4 to the right.

Number 2 and Number 3 engines were found in the area of the main wreckage with Number 2 engine to the left of the area and Number 3 to the right (Figure 6). The Number 3 engine was found lying in a large uprooted tree on a slope which was considered unstable and a thorough examination of the engine was not possible.


Examination of the Number 1, 2 and 4 engines revealed no evidence of fire,

uncontainment, or internal engine failure. There were varying amounts of damage to the engines and each had soil and tree debris packed between the fan blades. None of these engines showed any circumferential or spiral scoring to the fan spinner. The state of the engines examined was consistent with these engines not being under power at the time of impact.

3 Main wreckage site

The approximate GPS position of the main wreckage site was N05°58.725, 75◦25.138.

The main site was approximately 140 m from the initial impact site. Major assemblies identified included the cockpit, forward fuselage, wings, rear fuselage and the Number 2 engine. The wreckage had travelled downhill, passing through and disrupting trees (Figure 7).


The wings remained attached to the centre box (which forms the centre fuel tank) and were in the direction of travel but inverted. The orientation of the wings indicates that the centre fuselage rolled through 180° after the tail unit separated. The rear fuselage was upright but was facing opposite to the direction of travel. The majority of the rearpressure bulkhead remained attached to the rear fuselage. The left main landing gear was identified in close proximity to the rear fuselage. The side stay was locked, indicating that the landing gear was DOWN at the time of the accident.

The cockpit was disrupted and had been disturbed during search and rescue operations.

The position of switches and levers could not, therefore, be relied upon as being in the same position as at the time of the accident.

The centre console and throttle quadrant were identified.

The airbrake lever was slightly aft of IN.

All four throttle levers and the flap selection lever had been broken off in the accident.

The remains of the throttle levers were staggered and the remaining section of the flap lever was in the 30 DEG position.

The cockpit overhead panel was identified and its orientation was indicative of the cockpit section coming to rest inverted.

Both starboard wing flap screwjacks were fully extended, indicating that the flaps were in the 33 DEG, fully extended position at the time of impact. The port wing inboard screwjack was in the fully extended position. The port wing outboard screwjack was not accessible.

The starboard aileron, complete with servo and trim tabs, remained partially attached to the wing. It was not possible to identify the position of the aileron when the accident occurred.

The left wing was very badly disrupted and it was not possible to examine the port aileron.

The rudder and both elevators were still attached to the tail unit. It was not possible to identify the position of the control surfaces when the accident occurred.

The airbrakes were found slightly open.

The nose landing gear shock absorber piston, lower torque link and both wheels were identified approximately 15 m from the initial impact point, in the direction of travel.

4. Fuel

The starboard wing fuel tank had been split open during the accident sequence. With the exception of slight fuel odour in the immediate vicinity of the fuel tanks, there was no apparent evidence of fuel anywhere on the crash site.

The refuel panel (Figure 8) had a fuel upload of 9,300 kg selected. All the three fuel contents gauges within the panel indicated below zero, commensurate with readings when electrical power is removed. The three fuel valve selection switches were in the PRE-SELECT position.


There was no evidence of fire.

Fuel Planning Information

The operator had submitted flight information to a commercial flight planning company at1325 on 28 November 2016 in order to create a flight plan for the flight from Santa Cruz to Rionegro.

The route used to create the plan was the same as that used on the ATC flight plan submitted prior to departure. The plan gave a ground distance for the flight of 1,611 nm and a trip fuel requirement of 8,658 kg.

The only other fuel requirement submitted to create the plan was for a taxi fuel requirement of 200 kg. This gave a total fuel requirement for the flight of 8,858 kg, but with no allowance for diversion, holding or contingency fuel requirements.

The plan was created using a cruising flight level of FL300 and an aircraft takeoff weight of 32,991 kg. The plan recorded an increased trip fuel requirement of 64 kg for every additional 1,000 kg above this weight.

Other flight plans were found in the aircraft after the accident covering different routes.

These included a series of three plans created on 26 November 2016 covering separate flights from São Paulo to Santa Cruz, Santa Cruz to Cobija and Cobija to Rionegro. The Cobija to Rionegro plan had used Bogota as a diversion and included a diversion fuel requirement of 837 kg and a 30minute holding fuel requirement of 800 kg.

Estimated Load-sheet

The actual load-sheet was not located at the accident site nor has a copy been located elsewhere. In order to estimate the take-off weight for the flight the following information was used.


It is considered likely that the actual weight of baggage onboard the aircraft at the time of the accident was higher than the weight of the baggage recovered from the accident site. Baggage weight information obtained from the flight transferring passengers from São Paulo to Santa Cruz indicates that the baggage weight of those passengers transferring onto the accident flight was 1,026 kg. This would suggest a minimum estimated takeoff weight of 42,148 kg.

The maximum allowed takeoff weight for the aircraft, recorded in the aircraft Flight Manual is 41,800 kg.

ATC flight plan

The dispatcher accompanying the flight submitted a flight plan on 28 November 2016 at about 20:10hrs at the flight plan office at Santa Cruz Airport. The submitted flight plan gave a departure time of 22:00hrs and a cruising flight level of FL280. The flight time and endurance were both recorded on the plan as 4 hrs 22 minutes.

The flight plan office requested that the flight plan was changed and re-submitted due to the following issues with the plan:

  • The route did not include a standard instrument departure (SID) from Santa Cruz
  • There was no second alternate airport included in the plan
  • The estimated enroute time (EET) was the same as the endurance
  • The dispatcher had only signed the plan but had not printed his name

The dispatcher apparently had refused to change any of the details and explained that, regarding the EET and endurance being the same, the actual flight time would be less than that on the plan. The flight plan office filed the flight plan at about 20:30hrs but sent a report to the DGAC regional office giving details of the incident, stating that under the regulations the office was not empowered to reject the submission.

Further actions

A team of investigators carried out a visit to the DGAC facilities in Bolivia in order to gather information about the Operator and Regulations. The DGAC of Bolivia and the Prosecutors in La Paz, Cochabamba and Santa Cruz contributed and provided all the support to verify the Operators documents; however, the AASANA institution did not provide any information, related to the air navigation services and interviews.

The actions that were taken by DGAC (Bolivia), as result of the information regarding the accident, the operator’s Air Operator Certificate (AOC) was suspended.

The evidence available to the investigation at the time of issue of this preliminary report has not identified a technical failure that may have caused or contributed to the accident.

The available evidence is, however, consistent with the aircraft having suffered fuel exhaustion.

The investigation into the accident continues and will concentrate on issues related to fuel planning, decision making, operational oversight, survival and organizational oversight.

GRIAA will publish a final report once the full investigation is completed.

Information updated on 22, December 2016, 20:26hrs.


Unidad Administrativa Especial de Aeronáutica Civil de Colombia


Excerpted from

  1. PRELIMINARY REPORT Investigation COL-16-37-GIA. Fuel Exhaustion. Accident on 29, November 2016. Aircraft AVRO 146-RJ85, Reg. CP2933. La Unión, Antioquia – Colombia


  1. Normalization of Deviance: when non-compliance becomes the “new normal”
  2. The Organizational Influences behind the aviation accidents & incidents


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