The New Research Aircraft ISTAR - Experimental Flight Control System

Abstract

This paper describes the design of DLR’s new research aircraft Falcon 2000LX ISTAR (In-flight Systems & Technology Airborne Research). After having received the modified aircraft in 2020 additional modification phases shall enhance the capabilities of the aircraft for its future application as Variable Stability System (VSS) and for rapid inflight testing of any Guidance, Navigation and Control (GNC) research software application. The most essential modification of the aircraft will be the integration of an Experimental Flight Control System (EFCS) allowing control surface inputs generated by uncertified research flight control hard- and software. To operate the EFCS a specific safety and operational concept is required. New failure conditions introduced by the integration of the EFCS have been defined to perform a Functional Hazard Analysis (FHA) leading to functional safety requirements, such as reliabilities and Functional Design Assurance Levels (FDAL), for each function. For the criticality assessment of certain failure condition pilot-in-the-loop simulations have been performed in the Air Vehicle Simulator (AVES). Based on the performance and safety requirements a preliminary EFCS design has been defined.