The Influence of Surprise on Upset Recovery Performance in Airline Pilots

ABSTRACT Objective: The aim of this study was to test if performance of airline pilots, in performing an aerodynamic stall recovery procedure, decreases when they are surprised, compared to when they anticipate a stall event. Background: New flight-safety regulations for commercial aviation recommend the introduction of surprise and startle in upset prevention and recovery training. This calls for more evidence on the effects of surprise on pilot performance, as well as methods to effectively induce surprise in training simulators. Method: The study took place in a motion-base simulator with a poststall aerodynamic model. Using a within-subjects design, the recovery performance of 20 pilots was tested in 2 conditions: 1 anticipated condition, and 1 surprise condition. In addition to flight parameters, subjective and physiological data relating to surprise and startle were measured. Results: Pilots had significantly more difficulties with adhering to the recovery procedure in the surprise condition compared to the anticipation condition. The subjective and physiological measures confirmed that the manipulation mainly increased surprise, and to a lesser extent also startle. Conclusion: The results suggest that pilots have more difficulty in managing an upset situation (i.e., an aerodynamic stall) when this situation is presented unexpectedly, underlining that upset prevention and recovery training should include elements of surprise.