This aim of the study was to provide objective data to inform
fatigue risk-management processes by determining the quantity and
quality of sleep obtained by airline pilots during transcontinental
back of clock operations, and any changes to subjective fatigue and
neurobehavioural performance during these sectors. Typical
transcontinental back of clock route pairings involve a departure
close to midnight Perth local time, with a dawn arrival into an
East-coast city such as Melbourne, Sydney or Brisbane. In many
instances this first sector is followed by a second sector to
another east-coast destination, with sign-off at approximately 0900
Eastern Standard Time. Data were collected by participants during a
two-week period of a normal rostered flying for an airline. During
each of the 14 days of data collection, participants were required
to undertake the following: 1) Wear an activity monitor wristwatch
7 days prior to, and 6 days after, a transcontinental back of clock
flight; 2) complete sleep and duty diaries, which record time of
sleep, subjective alertness, and time of duty; and 3) complete a
simple 5-minute Psychomotor Vigilance Task (reaction time task)
during the cruise of each sector, and three times on non-flying
days. The results of this study suggest that Australian
transcontinental back of clock operations, as operated by the
airline involved in this study, differed significantly from a
baseline sample of daytime duty periods in a number of important
areas with respect to prior sleep, neurobehavioural performance,
and subjective fatigue. While there were some significant
differences in sleep and subjective fatigue as a function of a
single transcontinental sector of back of clock flying, these
differences were, on average, of a magnitude that was unlikely to
impact on flight crew performance and overall safety. However, when
a primary transcontinental sector is followed by an additional
east-coast sector, there is evidence of reduced prior sleep,
impaired neurobehavioural performance, and high levels of
subjective fatigue.