Typically, there are over twenty radio systems on board the average commercial jet aircraft dealing with communication, navigation and surveillance functions. Very high frequency (VHF) air-to-ground communication is usually the main method of information and control exchange between pilot and air traffic control. Satellite and high frequency radio links are used to complement this system for long range or oceanic information exchanges. Other communications systems are required between the airline operation centre and the pilot and sometimes between the passengers and the ground.

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