Abstract
The research presented in this thesis focuses on the evaluation of haptic feedback through coupled flight control inceptors on monitoring pilots on the flight deck. The study has three main objectives. The first is to evaluate the effects of haptic feedback on the flight deck in the literature. The second is to determine whether there is a statistical association between the number of accidents/incidents and the presence of haptic feedback on the flight deck. The third and final objective is to evaluate the effects of haptic feedback on pilots’ monitoring ability on a multi-crew jet aircraft in an experimental setting.In the last 15 years, there has been a notable rise in the integration of fly-by-wire control systems by aircraft manufacturers, with a particular emphasis on the incorporation of passive sidesticks lacking active control force feedback. This shift away from historically interconnected flight control inceptors has implications for the perception of flight control inputs between pilots. Field and Harris (1998) and Uehara (2014) concluded that the interconnection between flight controls is one of the essential ways in which pilots communicate. The static nature of passive sidesticks imposes limitations on the ability of the pilot monitoring (PM) to monitor the actions of the pilot flying (PF), potentially impacting performance and contributing to significant accidents, such as was the case in the AF-447 accident.
Two statistical studies were conducted to determine whether the considerations regarding the use of passive sidesticks were apparent in the number of accidents. Hard landing as well as tailstrike accident and incident reports have been retrieved from 72 national air accident investigating bodies, yielding a total of 514 air accident and incident reports, of which 40 qualifying hard landing reports and 129 qualifying tailstrike reports were used. Both studies show that hard landing and tailstrike accidents indicate a significant association between the number of accidents and the type of flight control. Although passive sidestick aircraft flew only 31% of all jet aircraft flight cycles in a ten-year time span, they were involved in 47.5% of the recorded hard landings and 41.8% of the tailstrikes. Although significant associations were found on the number of accidents, it remains uncertain what causes the elevated accident rates on passive sidestick aircraft.
Two human-in-the-loop simulator studies have been conducted with 20 commercial airline pilots in a fixed-base Airbus A320 simulator. The experiment compared monitoring on passive sidestick flight control configurations and active flight control configurations on several normal and abnormal flight scenarios. The participants were tasked with monitoring and intervening according to their company policy whilst a PF commenced normal take-off and normal landing scenarios, as well as non-flared landings and over-rotations during take-off in both passive and active flight control configurations. A large quantity of subjective, objective and physiological data was collected to determine performance, perceived workload and situation awareness (SA). The results showed that in 90% of scenarios, PMs on the active flight control configuration were effective in preventing the hard landing. By contrast, in the passive configuration, the PMs intervened successfully only 10% of the time. The results show that the active flight control configuration enables the pilots to anticipate an improperly initiated flare, thereby allowing them sufficient time to verbally and physically intervene successfully with less perceived workload and higher perceived SA. During the approaches flown in active configuration, pilots showed a significant increase in out-the-window (OTW) eye fixations, which strongly correlated with the perceived spare mental capacity, indicating a possible novel workload measure. During the over-rotation on take-off study, pilots showed similar improvements in successful interventions as in the hard landing study: In active configuration, 70% of the tailstrikes were successfully prevented, compared to 20% in passive configurations. In this study, pilots perceived significantly lower workload and greater SA.
In conclusion, the novel findings obtained from the literature, accident statistics and experimental studies presented in this thesis show that the passive configuration of the passive sidestick negatively affects a PM’s ability to anticipate future aircraft states, negatively affects the quality of the take-over action, and causes higher levels of workload as well as lower levels of perceived SA. The experiments show that the implementation of a cross-coupling between the flight control inceptors allows the PMs to perceive information throughout their haptic channel, which drastically lowers their perceived workload and significantly increases their ability to successfully intervene.
| Date of Award | Apr 2024 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Mike Bromfield (Supervisor), Steve Scott (Supervisor), Stewart Birrell (Supervisor) & Alex Stedmon (Supervisor) |