Phoning and flying

The passenger aircraft is one of the last places on earth yet to be invaded by the mobile phone. Safety is the major reason forbidding their use, with interference to navigation equipment cited as the principal hazard. Surprisingly, tests have shown that mobile phones actually work very well in the air. The aircraft structure does not prevent communication with the ground-the windows may well act as a form of slotted waveguide antenna-and coverage is excellent. The drawback, as far as the mobile operators are concerned, is that a mobile phone operating at 30000 ft can be seen by many cells at any one time, playing havoc with frequency reuse between cells. A number of approaches to enabling ordinary mobile phones to be used on board an aircraft have been studied. The author looks at some of the developments that should bring seamless communications from ground level to 30000 ft. In particular the author discusses the potential of aircraft based satellite communication using INMARSAT.