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)
AVIATORS’ LIFE STRESS & HOME BASED STRESS EFFECTS ON PERFORMANCE
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:
- 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:
- 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.
- 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.
- 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.
- 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.
- Efforts to suppress unwanted (stressful) thoughts consume a portion of finite cognitive resources, thereby impairing task performance.
- 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.
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)
- 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.
- The Effects of Life-Stress on Pilot Performance. James A. Young. NASA Ames Research Center, Moffett Field, California. December 2008
- 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
- On the Home Front. A stressful family life can affect performance in the cockpit. Patrick Chiles. AeroSafety World August July–August 2011.
By 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