Simulation and Integration Laboratory (SaIL) Testing of Integrated Cockpit and Fly By Wire

Modern vertical lift aircraft are complex and highly integrated systems that require careful design to guarantee safety and reliability. The Leonardo Helicopters AW609 Tiltrotor is one of the most complex and integrated systems in civil aviation. The AW609 relies on a full-authority, high-bandwidth, triplex-dual redundant architecture, fly-by-wire system which enables the flight crew to control transitions from helicopter to airplane mode, control the flight path of the aircraft, and manage the engine power demand. The AW609 Vehicle Management System (VMS) can manage and mitigate, in real-time, the system failures to ensure continuous safety of flight. The AW609 VMS is designed to a stringent set of requirements and objectives that meet or exceed the civil certification rules and allow the aircraft to satisfy its marketing objectives. As a result, many complex and highly integrated functions are integrated into the VMS and require rigorous methods of design assurance. This paper describes the use of hardware-in-the-loop simulation to verify qualitative safety assessments for Flight Control System (FCS) failure conditions that would be unsafe or impractical to fully evaluate in flight. Using the Simulation and Integration Laboratory (SaIL), it is possible to examine aircraft transients caused by a failure, crew recognition of the abnormal event, recoverability after the failure transient, and continued safe flight to landing in a thorough and efficient manner without presenting a safety risk to the flight test aircraft. The data illustrate that SaIL is an effective means to identify system problems and define emergency procedures that might be otherwise undetected and undefined from bench testing and stand-alone simulation. The net result of implementing SaIL methodology is an increase in level of system complexity and functionality without a corresponding increase in flight test time, safety risk, and cost.