Aerospace: Landing aircraft under poor conditions: Time-reference scanning beams characterize the all-weather microwave landing system that will replace present systems

Last April, a divisional meeting of the International Civil Aviation Organization (ICAO) settled upon a new all-weather landing system that will eventually replace the present instrument landing system (ILS) for aircraft. The choice of the United States/Australian time-reference scanning-beam microwave landing system (TRSB MLS) ended a selection process that started ten years ago in the U.S., and six years ago in ICAO, that, as the box on page 54 indicates, was not without controversy and debate.