A Comparison of Active Sidestick and Conventional Inceptors for Helicopter Flight Envelope Tactile Cueing

Results from two ground-based piloted simulation trials of helicopter flight envelope tactile cueing are presented. The objective of the trials was to develop methods of helping the pilot to observe flight envelope limits while conducting precise and demanding evaluation tasks. One trial used large-displacement conventional inceptors and the other used short displacement sidesticks. The inceptors in both trials were programmable and active. An analysis of variance has been carried out with inceptor type, tactile cueing, and head-up display cues as independent variables. The programmable nature of the active sidesticks enabled implementation of all conventional inceptor functionality including trim follow-up, beep trim, and trim release and yielded favorable pilot commentary regarding posture, feel characteristics, and controllability. With tactile cueing, conventional inceptors and the sidesticks yielded nearly equivalent performance. For both types of inceptors, tactile cueing significantly reduced the time required to reach the envelope limit, increased the dwell time at the limit, reduced exceedances, and improved pilot opinion. Tactile cueing enabled the pilots to easily track and respect notional dynamic limits designed to account for accumulated fatigue damage. Tactile cueing enabled the pilots to easily track both torque and rotor stall limits simultaneously while performing an aggressive turning task with their attention focused entirely outside the cockpit.