On effects of failures in haptic and automated pilot support systems

External aids are required to increase safety and performance during the manual control of an aircraft. Automated systems allow to surpass the performance usually achieved by pilots. However, they suffer from several issues caused by pilot unawareness of the control command from the automation. Haptic aids can overcome these issues by showing their control command through forces on the control device. It is possible to design Haptic aids that allow pilots to improve performance compared with the baseline condition, even if these are usually outperformed by automation. It is not very well understood yet however, what happens to performance in the event of a failure of the Pilot support system. To investigate how and if a pilot can recovery its performance after a failure of the haptic or automated support system, a quantitative comparison is needed. An experiment was conducted in which pilots performed a compensatory tracking task with haptic aids and with automation. Half of the runs were affected by a failure of the support system, resulting in complete removal of the support action. The haptic aid and the automation were designed to be equivalent when the pilot was out-of-the-loop, i.e., to provide the same control command. Pilot performance and control effort were then evaluated with pilots in-the-loop and compared to a baseline condition without external aids. As expected pilots performance is better with the automated support system, than with Haptic when no failure happens. When a Failure happens, pilots experience a sudden decrease of performance in both cases, but loss of performance is much higher in the automation case. In addition and somehow surprisingly, after the initial loss of performance, pilots flying with the Haptic aid return approximately to the performance level they had just before the failure, while pilots flying with Automation cannot re-gain pre-failure levels of performance, at least in the time span of the experiment.