E-4B crew fatigue associated with 30-hour IOT&E mission

The Air Force Test and Evaluation Center (AFTEC) conducted an independent 45-day IOT&E of the Advanced Airborne Command Post (E-4B aircraft) system from 27 December 1978 to 11 February 1979. A 30-hour continuously airborne mission was flown 6-7 February 1979 to demonstrate the extended mission capability of the E-4B system. Using a battery of psychobiological measures, the Crew Technology Division of the USAF School of Aerospace Medicine (USAFSAM/VN) evaluated crew fatigue associated with the extended mission. The battery consisted of sleep surveys, subjective fatigue ratings, and mood surveys, as well as endocrine/metabolic indices derived from urine samples. Data were systematically collected from 66 crewmen at 4-hour intervals during the mission and for 3 1/2 days after the mission. The data were reduced for six functional crew groups: flightcrew, stewards, radio operators, radio maintenance technicians, aircraft maintenance technicians, and the National Emergency Airborne Command Post (NEACP) battle staff. Fatigue and stress levels that occurred during the 30-hour mission were moderate and not suggestive of compromises in performance and safety. Fragmented sleep acquired in the bunks and passenger seats was of restorative value and contributed to the abeyance of severe fatigue and negative mood states during the mission. Severe levels of subjective fatigue were reported a few hours after mission completion, but after 2 nights of uninterrupted sleep in the home environment, the crews were sufficiently recovered to resume normal ground and flight duties.