What is Fatigue and how can pilots mitigate the effects of Fatigue
• noun 1 extreme tiredness. 2 brittleness in metal or other materials caused by repeated stress.
(Oxford Compact Dictionary)
Fatigue as a causal factor of aircraft accidents is often overlooked. There is a culture of blame and finding human error to attribute as the causing factor of the accident. This article aims to educate on the risks and implications of operating under a condition of fatigue and citing a higher involvement of fatigue in flight crew resulting in accident. There are counter measures to fatigue that can be implemented and this will also be discussed in this report.
Since the recognition of human factors in aviation, fatigue has been amongst one of the most important issues in regards to human safety. Fatigue is rarely the only cause of an aircraft accident; generally it is one of many factors culminated that leads to the occurrence of an accident. However, looking at statistics of fatigue as a causal factor of any aircraft accident, fatigue as a condition must be understood.
A general definition of fatigue is “a circumstance where less than the anticipated response is obtained” (MacIntosh, B.R). The detrimental effects of fatigue on the human body include sleepiness, lowered concentration and loss of situational awareness. The only way to combat fatigue is a healthy sleeping pattern and a healthy life style. As suggested and reported by Horne (1988) most individuals can adapt to a regime of having six hours of sleep per night without ill effect. The management of fatigue remains the responsibility of the individual; therefore, it is highly important that a pilot take the necessary steps to prevent the onset of fatigue. The symptoms of fatigue can have the effect of making a pilot complacent towards standard checks and procedures that are implemented for the safe operation of an aircraft. Often the omission of checks and procedures are the direct result of fatigue and the failure to complete these vital actions, known as DVA’s (Direct and Vital Actions) is a potential hazard and can lead to a total loss of flight safety. Fatigue lowers response to an environmental change and detrimentally effects good decision making, increasing the risk factor of an incident or accident to occur.
Fatigue is an under reported occurrence in aviation and is often difficult to diagnose the symptoms. Many counts of fatigue are likely to go unreported for reasons such as, fear of prosecution or loss of reputation. It is these ideal reports that will help identify the true nature of the issue and to find trends in the development of fatigue in the flight crew.
The focus of individual errors in the investigations into the cause of aircraft accidents must be avoided. Instead, there should be more focus into all aspects that pertain to any particular flight. A wider approach must be observed and every factor considered, identifying the smaller occurrences both in an operational and organizational aspect that lead to an accident. This is demonstrated in the James Reason Model (appendix 1 pg.8), that in order for an accident to occur, a series of ‘loop-holes’ must line up creating a hole through the organisational barriers. For example, a series of errors must be made starting well before the pilot made his final error. It is due to this approach of investigation that one can look at an accident or incident and ask how to avoid such a thing happening again instead of focusing on accusation.
Estimations between researchers vary but figures indicate that fatigue is a causal factor in nine percent of aviation incidents. It is an under-reported problem in aviation and the need for practical steps and measures to be implemented has been recognised.
CAA Manager Safety Analyst, Peter Nalder, says he would expect the real figure to be more like twenty-five percent. (Vector Magazine Nov/Dec 00). With this in mind, it can be observed the cited figure of nine percent is in fact a noticeable understatement. To support this on an international scale, the US NTSB (National Transport Safety Board 08) cited figures as high as thirty to forty percent or respondents experiencing fatigue or exhaustion.
Solutions for managing fatigue are not straightforward, but they can be developed through the cooperative efforts of scientists, regulators, managers, and the pilots minimising the effects of fatigue to ensure an enhanced level of aviation safety. (Caldwell 2004) A broad approach is to be observed when considering installing systems to combat the issue of fatigue in aviation. Firstly, we must consider the systems from an organizational perspective. Flight schedules should not be prepared in order to achieve legal maximums. Ideally, schedules should be prepared having given consideration to various different factors including a pilot’s circadian rhythm and giving sufficient time to sleep. As well as improved scheduling systems, the organisations should have a high level of understanding of the intricacies and complex nature of fatigue, and education to all employees, particularly pilots, should be implemented.
Major airlines could potentially build statistical data bases of their operations, based on anonymous pilot reports. This method is seen in websites such as PPRUNE (Professional Pilots Rumour Network) and could be well suited for airlines gathering information and receiving very specific and targeted data. This would enable management to categorise factors of risk in their operations. Scheduling factors, sleep deprivation, circadian disruptions, and extended duty periods continue to deprive pilots of alertness and performance. However, with the increased knowledge of sleep, fatigue, and circadian rhythms, this has allowed the aviation community to develop strategies and barriers to minimise the impact of fatigue on flight crew. Integration of this knowledge into organisational management practices will facilitate crew schedules designed to optimise alertness in the flight deck (Dinges, 2009).
Noticeable fatigue issues are reported by pilots. Blame must not be placed on organisational methods employed by the operator without first considering the factors relating directly to the pilots, and the discretion time flight that appears to be related to fatigue across all airlines (Jackson& Earl, 2006). Investigating pilots, a number of questions need to be considered in order to identify the fundamental reasons for pilot fatigue; are the pilots receiving adequate down time for the operation they are conducting? How are the pilots spending that time? Do the pilots recognise the importance of personally managing their own fatigue? Are the pilots aware of how to diagnose the effects of fatigue on themselves? Half of these questions directly relate back to organizational responsibilities in regards to education of employees however, it still remains the responsibility of the pilot to ensure he/she is adequately prepared and well rested at the beginning of a flight.
The final aspect to be examined when considering fatigue analysis is the governing authority, New Zealand Civil Aviation Authority. Regulatory limitations focused at limiting flight hours and ensuring adequate levels of flight crew rest times have, to a certain degree, reduced fatigue-related considerations in the flight deck environment. The regulations and limitations regarding crew flight time are laid out in Part 121 subpart K of the civil aviation act. Under section 121.803, the rule lists the responsibilities of the operators. Air operators are required to submit to the director a proposed scheme to combat the issue of fatigue provided that scheme adheres with the following limitations:
No more than 100 hours flight time in 28 consecutive days. A period of two days free of duty in any 14 day period. Not less than 2 consecutive days free of duty in any 30 day period and no more than 1000 hours in a 365 day period. (NZCAA Act 1990 Part 121 subsection K)
The scheme proposed must take into account rest periods before flight, acclimatisation, time zones, night operations, number of sectors to be flown, single or multi crew operation and any supplemental flight crew, standby periods, in-flight relief, type of operation, cumulative flight and duty time. Other factors include flight into discretionary time, circadian rhythm and days off. Air operators must not cause or permit any pilot to operate an aircraft if fatigue is suspected in that pilot. The scheme that an air operator puts forward must be approved by the director and strictly adhered to by the operator. The CAA invests the vast majority of its time into safety and avoidance and is the opinion of the author that the authority adequately accounts for fatigue in the Act.
The effects of fatigue in aviation have always been, and will continue to play a major role in the loss of flight safety. It is clear from this study that fatigue plays a greater role in aviation accidents than the argued figure of nine percent. But whatever the statistic truly is, when an accident occurs, the chances of fatality are high and it is the human component we are trying to protect. With education and improved awareness of fatigue even one life saved is a step in the direction of eliminating fatigue in the cockpit. It is each individual involved in aviations responsibility to ensure they receive adequate sleep and rest in order to enable them to perform at their optimum on every duty. From the pilot to the many factions of flight support, every action has an equal and opposite reaction. Every faction has a job to complete and every job must be performed by personnel operating at peak performance otherwise each protective barrier will line up and an accident ‘loop hole’ (James Reason) will occur. A culture of education and awareness of the dangers of fatigue in the cockpit will help cultivate a respect towards the issue ensuring pilots and operators recognise the effects of, and minimising fatigue.
• CAA Act
Part 121 – subpart K 23rd October 2008
• Caldwell, J. (2004) Fatigue in Aviation, Travel Medicine and Infectious Disease, May 2005, Vol. 3, Issue 2, Pages 85-96.
• Dinges, D. Journal of Sleep Research, Vol.4, Issue s2, Pages 4-14. Published online 20 January 2009. Retrieved 20 April 2009.
• Dr. Samuel, Strauss, DO, MPH
NASA/ Johnson Space Center
• Horne, J. (1988), Why We Sleep, Oxford University Press, New York.
• http://www.pprune.org/, retrieved 29 April 2009.
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• Jackson, C and Earl, L (2006) Prevalence of fatigue among commercial pilots in Journal Occupation Medicine, Issue 56, Pages 263-268.
• MacIntosh, B.R., and Rassier, D.E. (2002). Canadian Society for Exercise Physiology. What is fatigue? Can. J. Appl. Physiol. Vol 27, Issue 1, pages 42-55.
• Oxford University Press (2000) Oxford Compact Dictionary.
• Rosekind, M. (1994) Fatigue in operational settings: Examples from the Aviation Environment. NASA Ames research center: California
• Schiavo, M and Chartrand, S (1997) Flying Blind, Flying Safe. Avon Books: United States of America.
Daniel Tear 01087691