Human Systems Integration Division @ NASA Ames

This study examines pilots' ability to join (or rejoin) a flight that is already in progress. These situations naturally arise when pilots work in shifts, or are removed from active participation due to distraction or complacency. Twelve pilots assumed control of an airplane in the midst of two instrument approaches and asked to fly the remainder of the approach and missed approach procedure. During one approach, pilots were given a two-minute period to look about, review the instrument approach procedure, and prepare themselves to take over the controls. During a second approach, pilots were given no time to prepare, handed the approach procedure, and asked to assume control of the airplane immediately. As a control, pilots also completed a third approach and missed approach during which they flew continuously, without interruption. Surprisingly, there were no differences in the number of errors committed by pilots in any of the three conditions. Pilots who were given no time to prepare reported significantly higher levels of workload, but there was no difference in reported workload when pilots had time to prepare and when they flew continuously. Pilots who flew continuously reported comparatively greater awareness, but these differences narrowed over time when pilots had two minutes of preparatory time. The results encourage further study of the pilot-into-the-loop problem and the development of aids to support pilots more effectively in situations in which participation is intermittent.