Like most airline passengers, you probably have serious doubts about those pre-flight announcements asking you to turn off your cellphones, blackberries, iPods and anything else electronic.
The announcements are flat-out ignored by many frequent fliers, who are skeptical that so-called "personal electronic devices" pose any safety threat to airplane. Some passengers openly rebel, like New York Sen. Chuck Schumer, who cursed out one flight attendant who demanded he turn off his cellphone.
But a confidential industry study obtained by ABC News indicates there really could be serious safety issues related to cellphones and other PEDs.
A report by the International Air Transport Association, a trade group representing more 230 passenger and cargo airlines worldwide, documents 75 separate incidents of possible electronic interference that airline pilots and other crew members believed were linked to mobile phones and other electronic devices. The report covers the years 2003 to 2009 and is based on survey responses from 125 airlines that account for a quarter of the world's air traffic.
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.
The report, which stresses that it is not verifying that the incidents were caused by PEDs, includes a sampling of the narratives provided by pilots and crewmembers who believed they were experiencing electronic interference.
"Auto pilot was engaged," reads one. "At about 4500 ft, the autopilot disengaged by itself and the associated warnings/indications came on. [Flight attendants] were immediately advised to look out for PAX [passengers] operating electronic devices. ... [Attendants] reported that there were 4 PAX operated electronic devices (1 handphone and 3 iPods)." The crew used the public address system to advise the passengers to shut off electronic devices "for their safety and the safety of the flight," after which the aircraft proceeded "without any further incident."
In other 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."