Air Safety - Coming Down without a Bump

E. So in t1978 the ICAO chose the Microwave Landing System (MLS) to replace the ILS. The MLS also uses two radio signals from similarity sited transmitters to guide down aircraft, but there the similarity ends. The MLS uses narrow beams at a much higher frequency sweeping and forth across the path of incoming flights. A receiver on an aircraft registers when the beams pass and works out its angle to the runway from the timing of the signals. The new system is significantly less susceptible to interference than the ILS. And because its signals fan out wider, aircraft can make long curving approaches. This sometimes helps controllers manage traffic.