Cost-Benefit Analysis and Specification of Component-level PHM Systems in Aircrafts

Abstract


 
 
 Unplanned aircraft ground times caused by component failures create costs for the operator through delays and reduced aircraft availability. Unscheduled maintenance on the other hand also creates costs for Maintenance, Repair and Overhaul (MRO) companies. The use of PHM is considered to improve the planning of component-specific maintenance and thus reduces consequential costs of unscheduled events on both sides.This study assesses the component-specific costs and characteristics of today’s maintenance approach. A discrete event simulation represents all relevant aircraft maintenance processes and dependencies. For this purpose the Event-driven Process Chain (EPC) method and Matlab/SimEvents are used. The data input (process information, empirical data) is provided by a particular MRO company.Whereas recent approaches deal with stochastically processed data only, e.g. failure probabilities, the proposed method mainly uses deterministic data. Empirical data, representing particular dependencies, describes all relevant stages in the component lifecycle. This includes operation, line and component maintenance, troubleshooting, planning and logistics.By simulating different scenarios, various maintenance future states can be evaluated by analysing effects on costs. The obtained economical and technical constraints allow to specify component-level PHM design parameters, as minimum prognostic horizon or accuracy. Detailed process-specific information is provided as well, e.g. costs of non-productive MRO activities or no-fault-found (NFF) characteristics.