Development and Evaluation of an Electronic Vertical Situation Display

Abstract

Current advanced commercial transport aircraft, such as the Boeing B777/B747-400, the Airbus A320/A340 and the McDonnell Douglas MD-11, rely on AutoFlight Systems (AFS) for flight management, navigation and inner loop control. These systems have evolved from straightforward autopilots into multiple computers capable of sophisticated and interrelated tasks. These tasks span the range from high level flight management to low level inner loop control. In addition, these systems provide envelope protection to prevent pilots from committing mistakes such as stalling the aircraft or lowering flaps at high speeds. Unfortunately, as these systems have become more complex and interconnected, a new class of problems has developed associated with pilots’ interaction with the automation. Many incidents have been reported where there exists some confusion between the pilots’ expectations of the AFS and what the system is actually doing (Corwin, 1995). This confusion has been termed a Mode Awareness Problem (MAP). After a description of the AFS, a formal definition of mode awareness problems is presented in Section 1.3 followed by representative incidents in which mode awareness problems are suspected as being a contributory factor.