If you’ve scoffed at the warnings not to use your cellphone or other “personal electronic devices” on airplanes, be warned: According to a new report, pilots and other airline staff have seen specific incidents where they believe interference from cellphones, iPods and other devices affected flight controls, navigation and other critical systems.

The confidential report from the International Air Transport Association was obtained by ABC News, and documents 75 incidents that pilots or other personnel believe were connected to cellphone or personal device usage:

Twenty-six of the incidents in the report affected the flight controls, including the autopilot, autothrust and landing gear. Seventeen affected navigation systems, while 15 affected communication systems. Thirteen of the incidents produced electronic warnings, including “engine indications.” The type of personal device most often suspected in the incidents were cell phones, linked to four out of ten. …

In … events described in the report, a clock spun backwards and a GPS in cabin read incorrectly while two laptops were being used nearby. During another flight, the altitude control readings changed rapidly until a crew member asked passengers to turn off their electronic devices. The readings returned to normal. “After an hour, changes were noticed again . . . Purser made a second announcement and the phenomena stopped.

Despite the report, and demonstrations by Boeing showing that cellphones and other devices emit signals above what the airplane-maker calls “acceptable limits,” not all experts are convinced of the problem. ABC News aviation expert John Nance, a former Air Force and commercial pilot, said: “There is a lot of anecdotal evidence out there, but it’s not evidence at all,” According to Nance, “if an airplane is properly hardened, in terms of the sheathing of the electronics, there’s no way interference can occur.”

Is It Really Safe to Use a Cellphone on a Plane? [ABC News via Consumer Reports]

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