A developing method of aircraft HIRF/L preventive maintenance program

The rapid development of electronization raises the intensity of electromagnetic radiation and brings avionics under harsh conditions, frequently resulting in significant failures. How to maintain aircraft´s protection capacity against HIRF/L (high intensity radiated fields/ lightning) in service has become an important issue. This requires that a preventive maintenance program of aircraft HIRF/L protection has to be developed during researching and developing of aircraft. However, how to develop the program in the aviation is still being explored. This paper presents methods of developing the program, combining the recent research findings of both civil aviation and military aircraft. This method mainly includes: 1) defining the levels of HIRF/L protection systems; 2) determining the maintenance tasks of Level A system by the protection degradation from ED (environmental deterioration) and AD (accidental damage), and Level B system by its similarity to other aircraft systems; 3) determining the maintenance interval; 4) packing the maintenance tasks. According to this method, the maintenance tasks and intervals can be worked out. Thus the capability of HIRF/L protection and safety flights are ensured.