Fly-by-wire robustness to flight dynamics change under horizontal stabiliser damage

Abstract

ABSTRACTAircraft damage modelling was conducted on a Boeing 747 to examine the effects of asymmetric horizontal stabiliser loss on the flight dynamics of a commercial Fly-by-Wire (FBW) aircraft. Robustness of the control system is investigated by analysing how characteristic eigenvalues move as a result of damage and comparison to the non-FBW aircraft is made. Furthermore, the extent of stabiliser loss that the system can successfully handle without loss of stability and acceptable performance is identified. The presented analysis of the results gives insightful knowledge to aid in the design of an improved FBW system with increased damage tolerance. A handling qualities evaluation is presented to provide an understanding of how the pilot perceives the damaged aircraft. The results of the study show that a generic FBW system improves robustness such that the aircraft is stable with 50% horizontal stabiliser loss. With 50% damage, the aircraft is controllable but unsafe to fly and may be unable to effectively complete its mission task.