The Science Behind ALPA’s Recommendations
for Flight Time/Duty Time

ALPA’s message for years has been simple. We need three basic elements to guide any change in the regulatory environment:

  1. Sleep. We must have a minimum rest period that provides for an 8-hour sleep opportunity at the right time of the day and before the next duty period.
     
  2. Duty. Time since awake and time on task (spent on duty) are driving factors in pilot alertness. The duty-day length must take into account the time the duty day started.
     
  3. Circadian. Basic protections will not always be adequate when multiple time zones are crossed or flying is done on the back side of a pilot’s physiological clock.

Let’s take each of these elements individually and look at some more specific details.

Sleep1:

After over 100 years of experimental work, this is what researchers know:

  • Adequate sleep sustains performance.
  • Inadequate sleep degrades performance.
  • Inadequate sleep creates risk and loss.

Why is sleep important?

  • Productivity
    • Personal
    • Corporate
  • Safety
    • Personal
    • Corporate
    • Public
  • Health
  • Well-being

What are the consequences of sleep restriction or deprivation?

  • Short term (minutes, hours)
    • Error, accident, catastrophe
  • Mid term (weeks, months, years)
    • Bad planning, inadequate strategizing, poor life decisions
  • Long term (years)
    • Overweight/obesity, Type II diabetes, sleep disorder breathing, metabolic syndrome, etc.

Duty:

The following are some factors that lead to limiting a duty day based on the time of report (work-schedule factors that affect sleep, circadian rhythms, and alertness2):

  • Early start times
  • Extended work periods
  • Amount of work time within a shift or duty period
  • Insufficient time off between work periods
  • Number of consecutive work periods
  • Insufficient recovery time off between consecutive work periods
  • Night work through window of circadian low (WOCL)
  • Daytime sleep periods
  • Day-to-night or night-to-day transitions (schedule stability)
  • Changing work periods (e.g., starting and ending times, cycles)
  • On-call or reserve status
  • Schedule predictability (i.e., available in advance)
  • Unplanned work extensions

Circadian:

Circadian factors alter the basic sleep and duty provisions due to sleep disruption, etc. The list of issues listed under "Duty" apply, but they are further magnified due to circadian disruption. The short story to circadian issues3 is that they:

  • Alter alertness and performance
  • Alter ability to obtain restorative sleep
  • Alter length of sleep
  • Affect duration of re-synchronization

Summary:

Sleep is the key. The only thing that fixes a loss of sleep is sleeping itself. The length of duty, where it occurs, and any circadian disruption affect not only the quality of work, but also the ability to obtain recovery sleep before the next duty. They are all factors that are intertwined and must be considered together. ALPA’s revised policy on Flight-Time/Duty-Time does just that.

Click here to read a brief history of ALPA’s involvement of Flight-Time/Duty-Time Rulemaking since the Association’s creation.

1 Gregory Belenky, M.D., Sleep and Performance Research Center, Washington State University.
2 Rosekind, M.R. “Managing Work Schedules: An Alertness and Safety Perspective.” In M.H. Kryger, T. Roth, W.C. Dement, editors, Principles and Practice of Sleep Medicine, p. 682 (2005).
3 Steven R. Hursh, PhD, president, Institutes for Behavior Resources; professor, Johns Hopkins University, School of Medicine.