Flight Test Validation of Thrust Axis Tactile Cueing System on AW609 Tiltrotor

Rotorcraft generations are defined by concurrent paradigm advances, and a key theme of next generation rotorcraft is the reduction of pilot workload through state-of-the-art fly-by-wire systems. A means of reducing pilot workload is envelope protection - allowing the crew to spend less time managing physical aspects of the aircraft and more time managing the mission. Tiltrotors operate in a wide envelope, hovering near the ground and cruising at 25,000 feet. The power management system needs to be versatile to protect against operating above transmission limits in helicopter mode and engine limits at high altitude in airplane mode. In this implementation, tactile cueing is used to provide the pilot immediate feedback to and management of the transmission torque. Through flight test, the methodology of power management using a first-limit based tactile cueing system is validated. This paper describes the feedback scheme as realized in the flight control system, then the dedicated engine handling flight test campaign and subsequent experimental results are presented.