The Application of Human Factors in Wake Vortex Encounter Flight Simulations for the Reduction of Flight Upset Risk and Startle Response
Authors: Rooseleer Frédéric , Kirwan Barry , Humm Elizabeth , Paola Moreno_Alarcon Diana 
Published: June 2022

The current top safety risk concern for commercial air travel in Europe is known as “Flight Upset”. This term, also known as “Loss of Control in Flight”, entails the flight crew suddenly finding themselves in an unexpected, complex, and even confusing situation that if not resolved quickly can lead to a major accident. Accidents such as AF447 and the two B737 Max accidents fall into this category. An undesirable aspect of such events is known as the “startle response”, wherein one or both flight crew, finding themselves in dire and dangerous conditions, may experience ‘startle’, which temporarily affects their cognitive functioning. This may only last half a minute, but its effect can have a severe impact on the survivability of such events. A Horizon 2020 research project called SAFEMODE, which aims to integrate Human Factors techniques into a unified framework for designers in aviation and maritime domains, is exploring the use of state-of-the-art flight simulation facilities to measure pilot performance in severe wake turbulence events, which can induce the startle effect. This is part of a broader use case within SAFEMODE to validate the design of a new Wake Vortex Air Traffic Alert for the Cruise phase of flight. A tactical short-term alert to the Flight Crew, ahead of the wake encounter, is seen as beneficial to reduce the startle effect and support the appropriate management of these conflicts. The envisaged risk-alerting logic relies on a ground-based predictor, connected to the Air Traffic Control system, displaying an alert to the En-route Air Traffic Controllers, who can then provide a cautionary advisory to the Flight Crew so they can take appropriate actions.The cockpit flight simulations involve type-rated flight crews in realistic and representative cruise flight conditions, using a Type VI Boeing 737-800 full flight motion-based simulator (also used for Upset Prevention and Recovery training programs). During the simulation runs, pilots are exposed to simulated wake vortex encounters, corresponding to a strong wake-induced upset (between 30 and 40 degrees of bank), with or without prior ATC wake caution, and varying the initial direction of roll between left and right to limit the simulation training effect.Human Factors measurements include workload, situation awareness, trust, acceptability-based user feedback, as well as psychophysiological measures such as eye-tracking and Electro-Dermal Activity (EDA). In particular, eye-tracking is expected to support the refined determination of the sequence of actions before and after detection, and the reaction of flight crews to the en-route ATC Wake alert.A cockpit flight simulation, via combining the analyses of psychophysiological measures, flight parameters, expert observations and subjective pilot feedback, enables evaluation of Flight Crews performance in preparing for, managing or avoiding wake encounter upsets with the new ATC wake alerts, showing the net safety benefits. Early results indicate that the simulations can indeed induce startle effect, and that repeated exposure enables flight crew to overcome it and manage the situation in a more measured and controlled fashion.