Is the Legal Minimum Eight Hour Rest for Airline Pilots Sufficient?
Flying an aircraft is a high skill, labor intensive task which requires utmost concentration and razor sharp reactions in case of emergencies. In recognition of this fact, the aviation world laid down strict regulations to govern the amount of rest period for pilots. These rest periods were made in an era where the speed of the aircraft was slow and the tempo of operational activity considerably lower than that which obtains today in the modern world. Prater (2007), very aptly states that:
“Currently, airline pilots are routinely assigned a duty day up to 15 hours, followed by only an eight hour break, followed by another lengthy duty day. Unfortunately, this eight hour minimum break does not provide an adequate opportunity for recuperative sleep. Let me be clear; the eight-hour break is not an opportunity for eight hours of sleep, but rather a period of time away from the aircraft. During the 8-hour break, it is not unusual for a pilot to be left with a maximum 4 or 5 hours per night sleep opportunity actually spent inside a hotel room”(5).
The hypothesis of this essay posits that there are serious doubts now being raised whether the legally mandated eight hours of sleep is sufficient for pilots or not as the pilots are rarely getting that quantum of sleep due to a variety of reasons.
Sleep is a normal activity very important for our well being. There are numerous theories which try and explain why organisms sleep. The Recuperative theory according to Milton (1994) states that “animals sleep so that physiological and biochemical repairs can take place”. As per the circadian theory, the normal wake-sleep cycle is about 25 hours. A free running 25 hour cycle then gets modified to tune in to the 24 hour natural day-night cycle. The circadian theory gives a good plausible reason as to why humans get ‘Jet lagged’. As we travel across time zones, the human biological clock, attuned to a particular place’s day-night cycle, is upset by the continually changing day-night durations. This leads to disorientation, tiredness and lack of concentration. The US Air Force Instruction (2006) requires their aircrews to get a minimum of 8 hours sleep to cater for circadian conflicts. The International Civil Aviation Organization (ICAO) and all the Air Forces in the world cite the circadian theory as a reason for determining mandatory rests periods for air crews.
Studies on the Effects of Sleep Deprivation on Pilots
General sleep deprivation studies have revealed that “In the most extensive, controlled dose-response experiment on chronic sleep restriction to date, the neurocognitive effects of 14 days of sleep limitation to no more than 4, 6, or 8 hours time in bed were compared with the effects of total sleep deprivation after 1, 2, and 3 nights without sleep” (Durmer & Dinges, 2005, p.123). Airline pilots nowadays, routinely clock about the same period of actual sleep. Recent aviation accidents studies conclude that there is a statistically significant increase in the rate of accidents beyond 12 hours time on duty. The National Transportation Safety Board (NTSB) of the United States and other accident investigation bodies are increasingly focusing on fatigue as a factor in aviation accidents. A study carried out by the Australian Transportation Safety Board (ATSB) on the effects of transcontinental flights on pilot efficiencies revealed that there were significant deleterious effects of lack of adequate rest when the pilots flew eastward and at times of circadian lows. The ATSB based their report on a scientific study of 82 volunteer pilots which was monitored by another 37 pilots over a two week period of normal flying operations. During the period, the participants had to wear a monitor wristwatch, maintain complete sleep and duty diaries and complete a simple psychomotor vigilance task on duty and off duty. The study revealed significant results which can be encapsulated by the following observation that:
“During secondary back of clock sectors, crews had obtained on average significantly less sleep in the 48 hours prior to both take-off and landing, compared with a baseline of daytime sectors. It was observed that on landing crew had a mean level of sleep in the prior 24 hours, and an average across the prior 48 hours, below 5.5 hours per night. —-. Lack of sleep for the pilots results in drop in vigilance, forgetfulness, lethargy, apathy, and poor decision-making, communication, and mood” (Matthew, Petrilli & Roach, 2007, p.21 ).
The study was significant because it established the fact that the time-bound 8 hour rest period did not really translate into actual rest on account of circadian mismatch created by flying through different time zones. In another excellent study on the effects of sleep deprivation was carried out by NASA’s Ames Research Center on a NTSB 1993 report of a DC 8 crash in Guantanamo bay. This study categorically proved that the 8 hour legal period did not really translate into actual rest for the Captain of the ill fated aircraft who because of the airline duty schedule had “In the last 28.5 hours prior to the accident been awake for 23.5 hours with 5 hours of sleep” ( Roskind et.al p.6). In fact, all cabin crew of that particular flight had deficit sleep on account of airline time schedules and duty periods. So great had been the sleep deprivation in the extant case that the Captain chose the more difficult approach runway despite being unfamiliar with the airport. In the seconds before the crash, the psychomotor response of both the captain and the copilot were decidedly slow to respond to the automatic audio stall warning. This was recorded by the Cockpit Voice Recorder and analyzed threadbare by the NASA research team. The pilot survived the crash and when asked how did he feel just before the crash, he replied that he had felt “lethargic and indifferent” (Roskind et.al p.9). This remark very clearly brings out the deleterious effect of sleep deprivation on the ability of pilots to take a sound judgment. The report also established yet again the dichotomy in the interpretation of ‘8 hours of rest’ and the actual situation as it is unfolding the world over in the airlines industry.
Present Aviation Working Environment
In the competitive airline industry, cutting costs and maintaining profitability has forced managements to try and get the maximum ‘quality work’ out of their pilots. Thus while on paper all airlines adhere to the eight hour rest period rule, actually the reality is quite different. Advances in aviation technologies are giving rise to new types of aircraft which are capable of long-haul operations in excess of 16 hours. This means that the aviation industry and regulatory bodies have to now ensure that two sets of crew fly one aircraft on a 16 hour flight. Also, the onboard facilities must now provide for crew rest rooms so that the mandatory eight hours of sleep is met. Even if the above conditions are met, there is no getting away from the fact that crossing over a dozen time zones in a 16 hour flight will result in circadian disturbances which will affect the pilots. The problems faced by pilots flying long haul flights are also mirrored by those flying short haul durations too. This is because, the industry may insist that a pilot fly night duty and then take his rest period. The words of a former airline staffer very aptly sum up the problem. According to Fairchild (2008):
“Pilots generally don’t disembark before passengers— So, once the plane is empty, the crew makes its way on foot from the back of the airport to curbside, stopping in Customs on international sectors, then standing outside waiting for the van sometimes for as much as 45 minutes.”.
The conclusions of almost all studies on sleep deprivation and pilot working schedules have revealed that the present legally mandated 8 hours is not sufficient for Pilots. The main reason for this lack of sufficiency has been the work culture and unrealistic time schedules of the airline industry. In an effort to derive maximum profits, the airline management strictly adhere to the 8 hour rule knowing fully well that practically the pilots are not getting the required rest. The high speed, high performance aircraft of the present generation require utmost concentration of the pilots whose body clocks are forever trying to adjust to changing time zones and the accumulating sleep deficit. The way forward is to have greater operational flexibility by developing more sophisticated fatigue risk management systems which holistically address the requirements of individual pilot flight schedule instead of blindly prescribing a timed ‘8 hour rest period’. This means that the system should look into the pilot’s last schedule, the number of hours of sleep deficit, the number of hours required to catch up on sleep, check his physiological and psychomotor responses, have self monitoring equipment strapped to the pilots and allow a flexible rest-work schedule to reduce the risk of aviation accidents.
Air Force Instruction 11-202, volume 3, 5 April 2006. Flying Operations – General Flight
Rules. Page 70. Retrieved on Jun 30, 2008
Durmer, Jeffrey S ; Dinges, David F. (November 2005). Neurocognitive
Consequences Of Sleep Deprivation. Retrieved on June 30, 2008 from
Fairchild, Diana. 2008. “Sleepless in the Cockpit”. Retrieved on October 17, 2008
Matthew J.W. Thomas, Petrilli, Renée M. ; Roach, Gregory D.. March 2007.
“The Impacts of Australian Transcontinental ‘Back of Clock’ Operations on
Sleep and Performance in Commercial Aviation Flight Crew”. Retrieved on
October 17, 2008 from
Milton, John.(1994). Recent Functional Theories of Sleep and Dreaming. Retrieved on
Jun 30, 2008 from http://www.epistemics.co.uk/staff/nmilton/papers/sleep.htm
Prater, John. June 6, 2007. “The National Transportation Safety Board’s Most
Wanted Aviation Safety Improvements”. Retrieved on October 17, 2008
Rosekind, Mark R, Gregory, Kevin B, Miller, Donna L, Elizabeth, Lebacqz, J. Victor and
Malcolm Brenner. “Examining Fatigue Factors in Accident Investigations:
Analysis of Guantanamo Bay Aviation Accident”. Retrieved on
October 17, 2008 from