The role of the International Civil Aviation Organisation (ICAO) in developing standards and recommended practices for communication, navigation and surveillance systems is well known. The emphasis is on system characteristics and the definition of airborne equipment is limited to essential characteristics. For many years, the world’s airlines have collaborated in the Airline Electronic Engineering Committee of ARINC to produce engineering characteristics to ensure interchangeability and hence freedom of choice in their selection of airborne equipments. Thus ‘box’ dimensions, types and pin connection, interfaces cabling, coding etc are covered.

For the electronics industry designing equipment to meet the needs of both the aircraft constructors and their customers, the airlines and the Airworthiness Authorities responsible for the certification of equipment installed in passenger carrying aircraft more detailed specifications are essential. This problem was recognised in the USA and a solution was found in the formation of the Radio Technical Commission for Aeronautics (RTCA). With the direct support and involvement of USA Government Departments, the Electronics and Aircraft Construction Industry, the Airlines and General Aviation operating as ‘Special Committees’ of experts, RTCA developed Minimum Performance Standards. These documents are used by the FAA as the basis for equipment certification.