SAE ARP5757

This SAE Aerospace Recommended Practice (ARP) provides guidance for substantiating the airworthiness of aircraft engine components. Generally these components are associated with the engine control system, the system or systems that allow the engine to provide thrust or power as demanded by the pilot of the aircraft while also ensuring the engine operates within acceptable operating limits. But these components may also include hardware and systems associated with engine lubrication, engine or aircraft hydraulic or electrical systems, aircraft environmental control systems, thrust reverser control, or similar aircraft or engine propulsion system functions.

This paper develops the concept of using a 26 item matrix of environmental conditions for evaluating aircraft engine component airworthiness. This approach is compatible with current practices used in the industry and has been accepted by engine certification authorities as part of engine certification programs.

The purpose of this document is to provide guidance on demonstrating compliance with aircraft engine certification authority requirements for engine components. Many complete engine tests are done as part of the overall engine substantiation and certification process. But often during the engine testing process it is not practical to exercise all of the components of the engine to the extreme environmental limits each will encounter during operation in service. A simple example is during on the ground engine demonstrations the various components may not be exposed to the range of ambient temperature that will exist in the aircraft application. Additional tests or analysis may be required to demonstrate that the component will operate successfully throughout the range of ambient temperature conditions. There are a number other environmental conditions and combinations of conditions that can best be evaluated at the engine component or subsystem level.

This ARP is written to address the engine components associated with a new engine program certification. But the guidance may also be used for validating design changes to previously certified engines. However, when using this ARP for substantiating design changes, all test parameter levels, times, and pass/fail criteria should be reviewed to make sure they are adequate for the already certified engine application.