I assume this is in the politics tab because it's a link to the NY Post?

http://spectrum.ieee.org/aerospace/aviation/unsafe-at-any-airspeed /0

Of the cockpit instruments that can be interfered with by RF emissions from portable devices, the most problematic might be those used for navigation. To understand what's at stake, we need to first note the variety of different technologies used today for aircraft navigation. The most common are the VHF omnidirectional range system and the instrument landing system, both of which operate near 100 MHz, and GPS, which operates between 1200 and 1600 MHz. PEDs have the potential to interfere with each of them, but the most serious concern has to be for GPS receivers, which are becoming key navigational aids these days--particularly when clouds or other weather problems make it impossible for pilots to see runways.

GPS-certified landing approaches are now widely used in general aviation. Though most airliners presently use instrument landing systems, use of GPS technology will increase significantly over the next few years. There are three times as many GPS-certified approaches as instrument landing system approaches in the United States.

In March 2004, acting on a number of reports from general aviation pilots that Samsung SPH-N300 cellphones had caused their GPS receivers to lose satellite lock, NASA issued a technical memorandum that described emissions from this popular phone. It reported that there were emissions in the GPS band capable of causing interference. Disturbingly, though, they were low enough to comply with FCC emissions standards.

Our data and the NASA studies suggest to us that there is a clear and present danger: cellphones can render GPS instrument useless for landings. Clearly, the cause of the problem is that the FCC issues RF emission standards for consumer electronics, conferring only minimally with the FAA and with no formal consideration of the implications of those standards for the aircraft environment. For its part, the FAA relies on the airlines to initiate safety plans and, like other government agencies, defers to the FCC on questions of electromagnetic radiation.

Have cellphones caused accidents? We cannot be sure they have, but the data support the belief that they may have. Without any direct record of the RF environment in a plane at the time of its crash, it is difficult to see how one could definitively attribute a crash to PED interference after the fact. This holds true even if investigators were to look for PED interference as the primary cause of the accident, which, typically, they do not.