1. FATIGUE Presented by Dr. Sam Nix, ATP Air Medical Pilot sam.g.nix@gmail.com

2. History “If I could throw myself down on a bed, I’d be asleep in an instant. In fact, if I didn’t know the result, I’d fall asleep just as I am, sitting in the cockpit—I’m beyond the stage where I need a bed, or even to lie down. My eyes feel dry and hard as stones. The lids pull down with pounds of weight against their muscles. Keeping them open is like holding arms outstretched without support. After a minute or two of effort I have to let them close.” - Charles Lindbergh

3. Present Mr. Lindbergh’s narrative demonstrates that fatigue has deep historical roots in aviation. Unfortunately, there is plenty of evidence to show that the problem is still with us today. A quick search of the internet will uncover numerous documented instances in which one or both pilots fell asleep at the controls. This probably isn’t a surprise to most pilots. In fact, many surveys demonstrate that pilots in all segments of aviation are concerned about fatigue during flight.

4. Research Fatigue research is generally limited to documenting that pilots experience fatigue. Studies that evaluate specific factors that may contribute to fatigue are limited. The information that does exist is not necessarily applicable in every segment of aviation. For example, the factors contributing to fatigue experienced by pilots of long- range aircraft transiting multiple time zones are not the same as the factors contributing to fatigue experienced by pilots of short-range air medical aircraft that operate around-the-clock. Similarly, fatigue countermeasures developed in one segment of the aviation industry may not benefit all segments.

5. Research The results of a study evaluating fatigue experienced by helicopter air medical pilots while on duty is presented as an example of focused research that may benefit fatigue management strategies. This study collected data to determine that extent that consecutive 12-hour day shifts, consecutive 12-hour night shifts, age, and experience as a helicopter air medical pilot affected fatigue. The research was conducted under the supervision of Northcentral University in Prescott Valley, Arizona.

6. Copyright Notice The results of this study will be published in the September-October issue of Air Medical Journal. Please contact the presenter prior to using any information from the remaining slides. sam.g.nix@gmail.com

7. Subjects Three hundred ninety-five on-duty pilots completed the Brief Fatigue Inventory* while on duty. Two hundred pilots were on day shift. One hundred ninety-five were on night shift. These 395 respondents represent about 11% of the estimated total population of helicopter air medical pilots in the United States. * Used with permission of the copyright holder.

8. Fatigue Scores Day shift fatigue scores varied from 1.4 to 6.0 with a mean score of 3.5. Night shift fatigue scores varied from 1.7 to 6.8 with a mean score of 3.7. The fatigue scores for both the day shift pilots and the night shift pilots were normally distributed. This characteristic suggests that conclusions drawn from this sample are probably representative of the population as a whole. The next slide shows the distributions for day shift and night shift fatigue scores.

9. Fatigue Scores

10. Interesting points: All pilots reported some level of fatigue regardless of the shift they were working. Thus, fatigue management strategies in this segment of the aviation industry should not be limited to night shifts. However … Statistical tests suggested that the mean fatigue score for pilots on night shift was significantly higher. Thus, fatigue management strategies should also recognize that helicopter air medical pilots on night shift may be more susceptible to the condition.

11. Consecutive Day Shifts Consecutive day shifts varied from 1 to 11 with the vast majority of pilots reporting 7 or fewer day shifts when the survey was completed. Statistical tests suggested that the effect of consecutive 12-hour day shifts on respondent fatigue scores was not significant.

12. Consecutive Night Shifts Consecutive night shifts also varied from 1 to 11 with the vast majority of pilots reporting 7 or fewer night shifts when the survey was completed. Statistical tests suggested that the effect of consecutive 12-hour night shifts on respondent fatigue scores was not significant.

13. Comment Many air medical pilots have significant rest opportunities while on duty. These rest opportunities could help explain why consecutive day shifts and consecutive night shifts did not affect fatigue scores. However, this possibility was not investigated during this study.

14. Observation There are two main scheduling models used in air medical operations. On requires pilots to work only day shifts or night shifts during a 7 calendar day cycle and the other requires pilots to switch from days to nights at the mid-point in the 7 calendar day cycle. The results of this study suggest that neither schedule model affects fatigue more than the other. This is an example of how what we intuitively think about fatigue may be misleading. Continued...

15. Observation Although it seems unlikely that pilots can quickly adjust from day shift to night shift at the midpoint, this was neither supported nor refuted by the data. Instead, it appears that the pilots working the alternative schedule may not be using much of their off-duty time to prepare for night shifts. In other words, there may not be much circadian rhythm adjustment on the first night shift regardless of the scheduling model used in air medical operations. Interestingly, a previous study determined that many air medical crews (pilots and medical) come to work with the expectation of obtaining rest while on duty.

16. Age Respondent ages varied from 26 to 66 years. Statistical tests suggested that the effect of age on respondent fatigue scores was not significant. This finding is divergent with studies in the general population suggesting that increased levels of fatigue are a normal consequence of age pathology.

17. Experience Experience as a helicopter air medical pilot varied from 0.1 to 25.5 years with most respondents reporting 10 or fewer years of experience. Statistical tests determined that experienced pilots are slightly more prone to fatigue than inexperienced pilots. This is consistent with studies in other occupations suggesting that we become less stimulated by occupational tasks as they become more routine in nature.

18. Closing Comments Risk assessment is conducted in a sterile environment. Risk mitigation occurs in the real world where hazards are actually encountered. Regardless of how we assess the risk of encountering fatigue, there is nothing we can do to completely eliminate the possibility that pilots will encounter fatigue during flight. Supporting mitigation by educating the pilot on factors that contribute to fatigue in the specific segment of the industry where that pilot works is the next best thing. This suggests that aviation fatigue research should start moving toward factors that cause fatigue.

19. Closing Comments Many air medical companies were reluctant to grant permission to survey pilots while on duty. This study was made possible only with the support of the National EMS Pilots Association. We cannot manage that which we do not understand. If you are in a position to do so, please encourage your company to support additional fatigue research.

20. Closing Comments Like all studies, the study results in this presentation have some limitations. Please contact the presenter if you would like to discuss this study in detail or if you would like a copy of the references. The presenter will also be happy to collaborate with other researchers who wish to conduct human factors research.