February 1993, recently a  DC-10 while on approach to New York's Kennedy Airport almost crashed when a passenger on board in first class had turned on his portable compact disc player. It is believed that the compact disc player interfered with the Instrument Landing System (ILS) signal on board while the aircraft was on its final approach. An aircraft out of Chicago veered of course when a passenger turned on his laptop.

Pilots have indicated  that passengers carrying on board such portable devices as cassette players, portable phones, tape recorders,  laptop computers and Walkman-type radios  are causing their navigational instruments to go wild. Apparently these devices when turned on causes a certain amount of electromagnetic noise which can interfere with the planes instruments. With the newer aircraft the low power circuitry is more susceptible to interference.  Pressed by pilots to crack down on passengers using portable devices, the Federal Aviation Administration issued an advisory that left it up to the airlines to set their own rules. Delta Airlines has already expanded its list of forbidden devices to include video playback machines and CD players.