Fatigue and Performance Degradation

By Jacqueline Booth-Bourdeau March 2001 When we talk about fatigue in aviation, we usually think in terms of the pilot world. We know that fatigue-induced human performance errors are a causal factor in many operational incidents and accidents. This realization has led to a profusion of research and regulatory activity in the form of duty time regulation. The pilot fatigue equation is easy to grasp. Pilots face operational demands that can include transmeridian travel, night work, shift work and irregular work schedules. We tend to focus on the pilot issue because of the immediate consequences of a fatigue-induced error. It’s a simple formula: pilot falls asleep, aircraft crashes. From the maintenance perspective, it’s not quite this clear-cut. The connection between fatigue and maintenance error is not as well defined, nor as well documented. This is in spite of the fact that the physiological challenges are still the same: shift work, night work and long working periods. The link between fatigue and performance impairment is somehow perceived as less critical, because the maintainer is not seen as being on the "front line." The fact remains, however, that many maintenance tasks are performed in the middle of the night when the propensity for human performance error is at its greatest. This assertion is borne out by a growing body of evidence documenting performance degradation at the circadian low point – the middle of the night. Fatigue related performance degradation is not isolated just to shift work and night work; it is also associated with long shift durations and the number of consecutive days worked. Professor Drew Dawson, at the University of South Australia, has equated fatigue related impairment to alcohol impairment. His research has shown that after 17 hours of wakefulness, fatigue related impairment is equivalent to a blood alcohol level of 0.05 percent. After 24 hours of wakefulness, this increases to 0.10 percent — well over the legally prescribed limit for operating a motor vehicle. Perhaps one of the most insidious aspects of fatigue is the inability of the individual to recognize when their own performance is deteriorating and to take the appropriate action. Of course, in the 24-hour a day aviation industry, it’s usually not possible to quit work when you’re feeling tired. The economic considerations of the aviation industry demand that maintenance be completed in the most expeditious manner, which often means continuing work until the job is done. There may also be good safety reasons for the occasional extension of working hours. For example, it may sometimes be necessary to weigh the possible effects of fatigue against the potential for miscommunication in handing over a partially completed job to another person. So what are the options? From the perspective of the individual there are measures that can be taken to manage fatigue. This might be as simple as informing ones self of the symptoms of fatigue, or as complex as a night shift adaptation program. Fatigue management, however, is a shared responsibility between the employee and the employer. In effect, the employer should ensure that all work-related causes of fatigue are effectively managed and the employee should ensure that all non work-related causes of fatigue are minimized. Accepting responsibility for fatigue management is an ideal scenario, whether it exists or not is another issue. From the Government perspective, the issue of fatigue management is not likely to be as simple as dictating duty time through regulation. After all, while duty time regulations do limit hours of work; it is impossible to regulate the hours that one sleeps. It is a common misperception that time off means restorative rest. Only sleep will restore alertness and only the individual can ensure that they get sufficient sleep. Having said this, we cannot afford to rule out duty time regulation as an option – especially given the increasing awareness of the role of fatigue in human error. Before we take any action in this regard, however, it is important to determine if there actually is a fatigue problem in the Canadian aviation maintenance industry. To this end, Transport Canada has commissioned a study to assess current working hours in the industry. The study is part of a three-pronged initiative that addresses fatigue-induced performance impairment. The project also includes an assessment of those maintenance tasks most impacted by fatigue. The third element is a fatigue management program. The results of the study will be used as starting point for a CARAC Technical Committee working group looking at fatigue and duty time limitations. The working group will determine the most appropriate course of action; this could include awareness and education programs or duty time regulation. We are already pushing ahead with the development of a fatigue awareness program. This will be used in combination with the maintenance task fatigue-impairment study as an education and awareness tool. Even if the Committee decides that duty time regulation is the most appropriate course of action, the Minister of Transport does not currently have the legal authority to make such regulations. An amendment to Aeronautics Act, giving the Minister of Transport the authority to regulate the working hours of the maintenance personnel, would be required. Transport Canada has already initiated an amendment to the Act, which, if accepted, will confer this authority on the Minister. For the reasons given earlier, however, having the authority, does not necessarily mean that it will be used. Any issue that directly affects both the professional and personal life of the individual is bound to be controversial. The issue of fatigue, and performance degradation as a result of fatigue, is no exception to this rule. The issue of fatigue is complex and multi-faceted, with no definitive solutions; however, it has been said that "—people who stay in the middle of the road—get run over"; and, as a regulatory authority, we have a responsibility to show leadership in this issue. Hence our move towards collecting the data required to make an informed decision regarding our options and our commitment to involve the maintenance industry in defining a solution to the problem.