In-Flight and Postflight Assessment of Pilot Workload in Commercial Transport Aircraft Using the Subjective Workload Assessment Technique

Abstract

A question relevant for Federal Aviation Administration (FAA) certification of pilot workload in new commercial transport aircraft is whether subjective evaluation of workload should be conducted in-flight or postflight. This article examines the effect of probe timing (in-flight or postflight) for subjective assessment of flights containing both low and high levels of workload using the Subjective Workload Assessment Technique. The B-727, FAA Phase 2-certified, 6-dr, motion-base simulator, and air traffic control simulation at the Man-Vehicle System Research Facility at the NASA-Ames Research Center were used. Each pilot flew three different flights: (a) a nominal flight (30 rain); (b) a communication flight in which the pilot was instructed to tune in and talk on the command radio, in addition to normal duties (30 rain); and (c) a malfunction flight, including two diversions and an engine and "A" hydraulic system failures (1 hr 30 min). Sixteen B-727 qualified airline pilots flew the three flights on two separate occasions in a test-retest paradigm. No effect for probe timing (in-flight or postflight) was found for the nominal and communication flights. A significant (Probe Timing x Phase of Flight) interaction was found for the malfunction flight. It appears that postflight ratings of high-workload events receive higher workload ratings than in-flight ratings of the same event.