Use of Workload Redlines: A KC-135 Crew-Reduction Application

In recent years, workload assessment has played an increased role in system design and evaluation. However, one concern in workload assessment has been the identification of how much workload is too much. This study established and used workload redlines in determining the feasibility of a two-person (no navigator) KC-135 conceptual cockpit design. Ten KC-135 crews and 2 KC-10 crews were required to fly several simulator missions over a period of 1 week. Objective and subjective measures of performance and workload were taken during and after each flight. The various performance measures and the subjective-workload measures provided convergent results supporting the feasibility of the conceptual design. Recommendations on the use of redline procedures and their future application are discussed.