Work/Rest Schedules and Performance of F/A-18 Aviators During Fleet Exercise 1992

As a continuation of our previous work during Operation Desert Shield/Storm, we examined the effect a fleet exercise has on the work/rest patterns, fatigue, and cognitive performance of F/A-18 aviators. For 10 days during Fleet Exercise 1992, 25 pilots from VFA-81 and VFA-83 completed daily work/rest logs while performing their usual tasks. Subjective measure of fatigue, quality of rest, and sleep need were also collected. A subset of these F/A-18 pilots completed a brief battery of cognitive tasks as soon before flying as possible and again after the flight debrief. As a group, the pilots were adequately rested with little or no problem sleeping, and they operated on a typical work/rest schedule for deployed F/A-18 aviators. However, in some instances during which late night missions were flown, sleep onset was delayed, coupled with shorter sleep periods and additional sleep problems. Several work/rest and flight related parameters were related to subjective measures of aircrew combat readiness, including: (1) flight quartile, (2) number and order of flights per day, (3) flight duration, (4) flight hours 72 h before a mission, (5) total work 24 h before a mission, (6) total sleep 12 h before a mission, and (7) total hours continuously awake before a mission. All seven variables significantly contributed to a multiple regression model derived using subjective strike delay, accounting for 51 percent of the variance. Moreover, statistically significant changes were observed from pre- to post-flight on a fatigue-sensitive reaction time task.