The synergistic incorporation of propulsive and conventional flight control to improve commercial flight safety

Abstract

This research was undertaken to investigate the feasibility of implementing thrust vectoring as a supplementary flight control system on civil transport aircraft. The motivation for this research was to explore loss of control in flight (LOC-I) mitigative strategies in the form of an alternative but dissimilar flight control technology, since thrust vectoring is inherently less dependent on aerodynamic effects than traditional surfaces. The research was conducted as a comparative study between conventional control surfaces and thrust vectoring under normal and abnormal flight conditions, and the operational boundaries of civil thrust vectoring were systematically quantified through comprehensive simulations and analyses. Desktop flight simulations were performed using the Transport Class Model (TCM) aircraft model developed by the National Aeronautics and Space Administration (NASA), representative of an underwing twin-engine configuration in line with current aircraft design trends.
The project was split into four phases to comprehensively evaluate aircraft behaviour in a wide range of scenarios. The first two phases focused on evaluating and comparing flight control effectiveness and aircraft controllability metrics respectively, while the last two examined the role of thrust vectoring as a backup flight control system in control surface failure events and aircraft upset conditions, respectively. Comparative analyses were conducted at different flight phases to highlight the advantages and limitations of thrust vectoring over conventional control systems across a typical civil flight profile.
The results demonstrated a general deficit of control effectiveness of thrust vectoring compared to conventional controls on civil transport aircraft due to their low thrust to weight ratio (TWR), however it was still capable of completing standardised manoeuvres to a satisfactory level. In addition, thrust vectoring was shown to mitigate the adverse effects of LOC-I precursors particularly at low altitudes, though it struggled to perform adequately at higher altitudes due to reduced available thrust.
The findings from this research prove the potential viability of thrust vectoring as a backup flight control system on airliners, and contribute valuable insights into the future design and implementation of advanced flight control technologies for improving aviation safety in commercial operations.

Date of Award	18 Jun 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Mark H Lowenberg (Supervisor) & Tom S Richardson (Supervisor)