The Research On Maintenance Program Determination Method For Civil Aircraft FBW Flight Control System

As the functionality and performance are enhanced in fly-by-wire (FBW)flight control system (FCS), failure modes of FCS equipments coupled withdiverse fault causes have become increasingly complex. Moreover, otheraircraft systems have the similar status as FCS does. Therefore, it is importantto explore an analysis method to work out a reasonable maintenance program,which can both reduce the analysis workload of the designers and ensure theintegrity of aircraft systems maintenance tasks. Also, shortening the intervalof maintenance tasks and reducing the airliners’ maintenance cost is aneffective measure to improve the competitiveness of modern civil aircrafts.This thesis makes an in-depth analysis on the working-out of aircraftsystems maintenance program, mainly discussing the following points:1. MSG-3Analysis: Taking the flap/salt control system as an example,this paper investigates MSG-3analysis process to identify systemmaintenance programs;2. Functional Hazard Assessment （FHA）,Failure Modes and EffectsAnalysis（FMEA）and Fault Tree Analysis（FTA） Analysis: Theseanalysis methods are utilized to confirm the system function, functionfailure, failure effect and failure causes. The FHA of flap/salt control system is defined and a failure tree for one catastrophic failurecondition (Classification I) is developed in this paper;3. Combined Analysis: This paper proposes an analysis method (thecombination of general method， associated airworthinessrequirements and quantitative FTA method) to optimize anddetermine system maintenance intervals, as well as demonstrate thismethod with specific examples.The method mentioned in the paper to determine maintenance tasks hasbeen applied in flight control system of a domestic regional jet project. Andthe initial scheduled maintenance tasks and intervals in this system have beenpre-approved by the Industry Steering Committee (ISC). In addition, thismethod is recommended to be used on a large civil aircraft project, or as theguidance or reference in other industries.