Rosekind, M. R., Miller, D. L., Gregory, K. B., & Dinges, D. F. (2000). Crew Factors in Flight Operations XII: A Survey of Sleep Quantity and Quality in On-Bard Crew Rest Facilities (NASA Technical Memorandum 2000-209611). Moffett Field, California: NASA Ames Research Center.

Modern long-haul aircraft can fly up to 16 continuous hours and provide a 24-hour, global capacity. Extra (augmented) flight crew are available on long flights to allow planned rest periods, on a rotating basis, away from the flight deck in onboard crew rest facilities (2 bunks). A NASA/FAA study is underway to examine the quantity and quality of sleep obtained in long-haul aircraft bunks and the factors which promote or interfere with that sleep. The first phase of the study involved a retrospective survey, followed by a second phase study to collect standard polysomnographic data during inflight bunk sleep periods. A summary of the Phase I survey results are reported here.

A multi-part 54-question retrospective survey was completed by 1,404 flight crew (37% return rate) at three different major US air carriers flying B747-100, 200, 400, and MD-11 long-haul aircraft. The questions examined demographics, quantity and quality of sleep at home and in onboard bunks, factors that promote or interfere with sleep, and effects on subsequent performance and alertness.

Flight crews reported a mean bunk sleep latency of 39.4 mins (SD=28.3 mins)(n=1,276) and a mean total sleep time of 2.2 hours (SD=1.3 hrs)(n=603). (Different flight lengths could effect overall time available for sleep.) Crew rated 25 factors for their interference or promotion of bunk sleep. Figure 1 portrays the average ratings for each factor across all three carriers. A principal components analysis of the 25 factors revealed three areas that promoted bunk sleep: physiological (e.g., readiness for sleep), physical environment (e.g., bunk size, privacy), and personal comfort (e.g., blankets, pillows). Five areas were identified that interfered with sleep: environmental disturbance (e.g., background noise, turbulence), luminosity (e.g., lighting), personal disturbances (e.g., bathroom trips, random thoughts), environmental discomfort (e.g., low humidity, cold), and interpersonal disturbances (e.g., bunk partner).

The majority (91%) of flight crew reported themselves as good or very good home sleepers. However, 71% of these good home sleepers reported difficulty with sleeping in the aircraft bunk "often" or the "majority of the time." Only 6% of the poor home sleepers reported "seldom" having difficulty in the bunk. Good bunk sleepers ("never" or "seldom" have difficulty in bunk) were found to be older than the group reporting usual bunk sleep difficulties (p<.001). On average, flight crew rated the effects of bunk sleep on their subsequent overall performance and alertness as "improved" to "very improved."

The findings demonstrated that flight crew, generally good home sleepers, do have difficulty sleeping in aircraft bunks. However, even with the difficulties, they reported a reasonable quantity and quality of sleep. This sleep was rated as improving subsequent performance and alertness. Factors that significantly promote and interfere with bunk sleep were identified and can be the basis for intervention strategies that maximize the quantity and quality of sleep obtained in aircraft bunks.

Download the full report in Adobe Acrobat .PDF format below.