Development of the RF HIRF environment

Current civil aircraft design make an increasing use of electrical and electronic systems to perform functions which are necessary for the continued safe flight and landing of the aircraft. The possible susceptibility of the systems leading to this malfunction and/or failure, coupled with the increased use of partial or complete composite materials for the fuselage resulting in a reduction in RF screening when exposed to high intensity radiated fields (HIRF), causes concern. The Federal Aviation Administration (FAA) and Joint Aviation Authorities (JAA) regulations require that systems operate satisfactorily in their intended environments. However, there are presently no regulations dealing specifically with the protection of electrical and electronic systems against the effects of HIRF. In 1986, the FAA and JAA initiated a programme to (a) determine and define the environmental electromagnetic field strength levels; (b) develop guidance material for test, analysis and approval; and (c) agree and promolgate regulatory standards. The FAA/JAA requested and received the participation of various international airworthiness authorities and industrial groups in developing proposed international standards for type certification.