AIRCRAFT CERTIFICATION: HIRF PROTECTION REQUIREMENTS FOR CIVIL AIRCRAFT SYSTEMS

The Federal Aviation Administration (FAA) requested the assistance of the Society of Automotive Engineers, Inc. (SAE) in developing the technical basis for protecting electrical and electronic systems on civil aircraft from the effects of High Intensity Radiated Fields (HIRF) generated by sources external to the aircraft. As a result, the SAE formed AE-4R, the Aircraft Radiated Environment Subcommittee, as a part of the existing AE-4 Electromagnetic Compatibility Committee. The objective of the AE-4R Subcommittee is to identify the HIRF environment, recommend test and analysis methods for demonstrating that aircraft systems are protected, and identify designs for aircraft and equipment which provide protection from HIRF. The FAA plans to use the results of work done by the AE-4R Subcommittee as the basis for new regulations for aircraft. Initial publication of these regulations for comment was planned for October of 1990, but this will be delayed until 1991 to allow more time to resolve open issues concerning the HIRF environment. Until these new regulations are issued, both the FAA and the Joint Airworthiness Authorities (JAA) in Europe have been and will continue to issue special conditions which require aircraft systems to be protected from HIRF. This paper describes the requirements contained in FAA and JAA special conditions, experience gained in the certification programs which have been conducted, and the differences between the special conditions and the recommendations of the AE-4R Subcommittee.