AIRCRAFT FLEET MAINTENANCE BASED ON STRUCTURAL RELIABILITY-ANALYSIS

A stochastic crack growth analysis methodology, based on the lognormal random variable model, is described and demonstrated for two practica l aircraft structural maintenance applications. In the first applicati on, a reliability centered maintenance analysis for evaluating aircraf t structural maintenance and supportability requirements and options i n terms of risk or reliability is demonstrated. The sensitivity of ini tial and reinspection intervals to variations in analysis variables is investigated using a cutout in an aluminum-lithium cheek frame. The s econd application is the maintenance scheduling for a fleet of aircraf t on a calendar year basis in terms of risk or reliability. The crack growth life dispersion due to material, service usage severity, and ai rcraft utilization rate on the fleet maintenance schedule are accounte d for. Aircraft fleet tracking data are used and the sensitivity of fl eet maintenance requirements to variations in the design stress levels and other variables are investigated and presented.