Go to the NASA Homepage
Search >
Click to Search
Human Systems Integration Division homepageHuman Systems Integration Division homepage Organization pageOrganization page Technical Areas pageTechnical Areas page Outreach and Publications pageOutreach and Publications page Contact pageContact page
Human Systems Integration Division Homepage
Outreach & Publications Sidebar Header
Go to the Outreach & Publications pageGo to the Outreach & Publications page
Go to Awards pageGo to Awards page
Go to News pageGo to News page
Go to Factsheets pageGo to Factsheets page
Go to Multimedia pageGo to Multimedia page
Go to Human Factors 101 pageGo to Human Factors 101 page
What is Human System Integration? Website
Publication Header
Flight Crew Alertness and Sleep Relative to Timing of In-Flight Rest Periods in Long-Haul Flights  (2021)
Abstract Header
BACKGROUND: In-flight breaks are used during augmented long-haul flight operations, allowing pilots a sleep opportunity. The U.S. Federal Aviation Administration duty and rest regulations restrict the pilot flying the landing to using the third rest break. It is unclear how effective these restrictions are on pilots ability to obtain sleep. We hypothesized there would be no difference in self-reported sleep, alertness, and fatigue between pilots taking the second vs. third rest breaks.

METHODS: Pilots flying augmented operations in two U.S.-based commercial airlines were eligible for the study. Volunteers completed a survey at top-of-descent (TOD), including self-reported in-flight sleep duration, and Samn-Perelli fatigue and Karolinska Sleepiness Scale ratings. We compared the second to third rest break using noninferiority analysis. The influence of time of day (home-base time; HBT) was evaluated in 4-h blocks using repeated measures ANOVA.

RESULTS: From 787 flights 500 pilots provided complete data. The second rest break was noninferior to the third break for self-reported sleep duration (1.5 0.7 h vs. 1.4 0.7 h), fatigue (2.0 1.0 vs. 2.9 1.3), and sleepiness (2.6 1.4 vs. 3.8 1.8) at TOD for landing pilots. Measures of sleep duration, fatigue, and sleepiness were influenced by HBT circadian time of day.

DISCUSSION: We conclude that self-reported in-flight sleep, fatigue, and sleepiness from landing pilots taking the second in-flight rest break are equivalent to or better than pilots taking the third break. Our findings support providing pilots with choice in taking the second or third in-flight rest break during augmented operations.
Private Investigators Header
Authors Header
Groups Header
Keywords Header
augmentation, circadian, in-flight, rest break, rhythm, sleep
References Header
Aerospace Medicine and Human Performance, Volume 92, Number 2, February 2021, pp. 83-91(9)
Download Header
Adobe PDF Icon  art00005.pdf (Download Acrobat Reader Click to download Adobe Acrabat Reader)
  (742KB) (application/pdf)
Go to the First Gov Homepage
Go to the NASA - National Aeronautics and Space Administration Homepage
Curator: Phil So
NASA Official: Alonso Vera
Last Updated: August 15, 2019