Aircraft fleet maintenance based on structural reliability analysis

Abstract

A stochastic crack growth analysis methodology, based on the lognormal random variable model, is described and demonstrated for two practical aircraft structural maintenance applications. In the first application, a reliability centered maintenance analysis for evaluating aircraft structural maintenance and supportability requirements and options in terms of risk or reliability is demonstrated. The sensitivity of initial and reinspection intervals to variations in analysis variables is investigated using a cutout in an aluminum-lithium cheek frame. The second application is the maintenance scheduling for a fleet of aircraft on a calendar year basis in terms of risk or reliability. The crack growth life dispersion due to material, service usage severity, and aircraft utilization rate on the fleet maintenance schedule are accounted for. Aircraft fleet tracking data are used and the sensitivity of fleet maintenance requirements to variations in the design stress levels and other variables are investigated and presented.