10 Apr Fatigue in Flight: Controlled vs. Uncontrolled Sleep for Airborne Pilots
Most people that have taken a long-haul flight will be familiar with the difficulties of trying to get some sleep while in the air. Those in the cockpit, however, face a different challenge as pilots need to stay awake throughout their journey. There have been various surveys conducted assessing fatigue and sleep in commercial pilots, with an estimated 56-75% of pilots admitting to unexpectedly falling asleep while in flight. Shockingly, 29% of those pilots that have fallen asleep have woken up to find their co-pilot also asleep. Pilots can also be prone to microsleep (i.e., sudden episodes of sleep lasting less than 15 seconds), with more than 75% of pilots experiencing episodes of microsleep in flight. These figures are particularly alarming considering that 21-23% of major aviation accidents are attributed to pilot fatigue.
One strategy that can be used to combat pilot fatigue is controlled rest in position (or CRIP), which allows pilots to take brief naps during flight under strict conditions. These conditions include: only one pilot may sleep at a time; sleeping is only permitted during particular non-critical flight windows; and the sleeping pilot must give prior notice to their co-pilot as well as a flight attendant. Further, pilots must follow strict protocols upon waking to combat any cognitive impairments caused by the post-sleep inertia period.
There have been multiple studies demonstrating that CRIP techniques can improve reaction times, awareness, and subjective alertness ratings during subsequent critical flight windows. Whilst two-thirds of commercial pilots approve the use of controlled rest techniques during flight, the generic public do not share this sentiment with most airline customers stating they are less willing to fly knowing that their pilots are allowed to nap. Due to the controversial nature of these techniques, CRIP is currently banned in the U.S., although it is allowed in other countries (including Australia).
Finally, it is worth noting that although a significant number of aviation accidents are attributed to pilot fatigue, it seems that this is primarily driven by a lack of sleep causing detriments to alertness and attention rather than the act of sleeping itself. Therefore, whilst the idea of your pilot being allowed to nap might seem scary, it may be more dangerous for them to try and force themselves to stay awake in a fatigued state.
Sources
Quental, Nuno & Rocha, João & Silva, Jorge & Menezes, Lídia & Santos, Jorge. (2021). The impact of cognitive fatigue on airline pilots performance. Journal of Airline and Airport Management. 11. 16. 10.3926/jairm.183.
Gaines, Alex & Morris, Megan & Gunzelmann, Glenn. (2020). Fatigue-Related Aviation Mishaps. Aerospace medicine and human performance. 91. 440-447. 10.3357/AMHP.5515.2020.
Winter, S. R., Carryl, J., & Rice, S. (2015). Controlled Rest in Position (CRIP): Consumer Perceptions in the United States. Collegiate Aviation Review, 33(1). https://doi.org/10.22488/okstate.18.100461