Air passengers send bad signals Aviation: Electronic gadgets,radios, laptap computers and cellular phones may doom an airliner by disrupting the plane's operating systems.

Sun Journal

October 09, 1998|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

Your airliner is flying in circles, waiting to land. You're bored silly, so you flick on your Walkman for some soothing music.

Suddenly, the plane lurches to one side and begins to fall. People around you scream. You figure you're going to die in a flaming air wreck listening to Kenny G.

Now consider that you may have triggered the accident by switching on the Walkman.

Air safety officials in Australia are investigating whether a Qantas airliner that fell 700 feet while waiting to land at London Heathrow Airport Sept. 4 was jolted off course by electronic interference from a laptop computer or some other electronic device used on board by a passenger.

The pilot regained control of the flight, and no one was injured. But authorities in Australia, the United States and elsewhere have recorded hundreds of incidents in which pilots reported that their cockpit navigation and control systems may have been snarled by passengers' electronic toys, music players, laptop computers, cell phones or pagers.

So far, however, nobody has proved that the threat is real.

The result, according to a North Carolina aviation consultant, is a weak, inconsistent and poorly enforced hodge-podge of government advisories and airline rules on the use of portable electronic devices, or "PEDs."

John J. Sheehan, president of Professional Aviation, Inc., who studied the phenomenon for the Federal Aviation Administration, says the FAA's response has been "too mushy, too indecisive."

"We need to come up with some uniformity based on some semblance of fact. And we don't have any facts," he says.

Kathryn Creedy, a spokeswoman for the FAA, says, "The jury is still out on the ultimate effects of PEDs. The data we currently have indicate that the advisory circular is the appropriate way to handle this issue. If new data become available, we would want to consider it and take appropriate action."

Sheehan was chairman of a committee of government and industry scientists who studied the problem for the Radio Technical Commission for Aeronautics, an advisory body to the FAA. Its past work has led to bans on airborne use of FM radio receivers and restrictions on laptops.

The three-year study concluded in 1996 that the risk of disaster, while tiny, was real enough to demand both more study and tighter controls on electronic devices.

The committee reviewed more than 300 incidents of possible interference reported by pilots around the world. "We found about 10 where a true cause-and-effect relationship could be established," Sheehan says.

In those, when the devices were switched off, the cockpit instruments returned to normal. And when the devices were switched on again, the problems returned.

On a 1993 flight from Denver to Newark, N.J., the pilot had to threaten confiscation of passengers' radios before they were all turned off and his crippled gyroscopes returned to normal.

Sheehan says his committee never managed to duplicate such interference under controlled conditions, but, "I have no doubt those events were real, honest-to-goodness events, and the precipitating cause was a portable electronic device."

The study for the FAA found that such devices emit tiny amounts of "inadvertent" electromagnetic radiation. The errant electrons appeared to exit the passengers' windows, flow through the airplanes' metal skin and into the various antennas that serve the planes' navigation systems. Given the right frequency, and the right electromagnetic environment, or "flux," as the aircraft flies through the air, Sheehan says, it could cause malfunctions.

The report warned that navigation systems that rely on weak signals from satellites orbiting 22,000 miles overhead may be especially vulnerable.

Interference from on-board electronic devices reportedly was studied as a possible factor in the 1996 crashes of the Air Force plane in Croatia that killed Commerce Secretary Ronald H. Brown, and of TWA Flight 800 off Long Island.

"Talk to any pilot who's been flying an electronically complex airplane for more than five years, and he will tell you that, on a weekly basis, he will see things on an airplane that can't be explained -- electronic hiccups," says Sheehan, himself a pilot. "I am constantly amazed at the strange things that happen on an airplane."

Sheehan says his committee warned the FAA that "until we get some definitive cause-and-effect relationships nailed down, we really shouldn't be allowing the use of PEDs during the critical phases of flight," that is, during takeoff and landing, when pilots may not have time to recover from a loss of guidance or controls.

Some on his committee felt all such devices should fly with the baggage. Even if the risk of catastrophe is one in a million, he says, "we don't think that's acceptable."

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