Expert: D. Norkus - 8/28/2006

Question
I know that during takeoff and landing all electronic devices must be turned off. What if everyone on the plane used their cellphones during a takeoff or landing? Would it disrupt the planes avionics and cause it to crash?

Answer
"What if everyone on the plane used their cellphones during a takeoff or landing? Would it disrupt the planes avionics and cause it to crash?"

While the chances may be slim they will actually create interferance, the chance is still there. Cell phones have the potential to interfere with navigation/communication systems as they operate on a close frequency/wave length.

Phones transmitting near the 1700 Mhz range were found to have caused these incidents on aircraft:

-Slaved Compass froze or overshot actual magnetic bearing
-Needles on instruments (engine/aircraft & nav) appeared unstable
-Digital VOR bearing display showed errors of 5 degrees
-VOR to/From indicator reading was reversed
-VOR & ILS* course indicator errors with & without a failure flag
-Sensitivity of the localizer was reduced
-Background noise in the audio system
-False warnings of unsafe conditions such as smoke alarms in the baggage compartments

In visual conditions such disruptions may not be that big of a deal, in poor weather they could cause havoc. Flying close to the ground, in poor weather, is not the time you want to get false readings from aircraft instruments!

*For more info on what a VOR & ILS does, see:  
http://en.wikipedia.org/wiki/VHF_omnidirectional_range
http://en.wikipedia.org/wiki/Instrument_Landing_System