For Real

Next time you're on a flight and the plane suddenly begins to climb or pitch to the left, don't panic. It's probably just the kid next to you conquering level 16 on his computer game.

Pilots have become accustomed to unexpected problems caused by passengers using mobile phones or other portable electronic devices.

Over the past decade there have been more than 100 incidents in Australia of navigation system failures, autopilot malfunctions, interference with radio transmissions, incorrect readings from flight management computers and false alerts from engine warning systems - all due to portable devices.

In one case last year, the ground proximity warning system in a 34-seater plane suddenly went berserk even though the plane - which was just 22 kilometers south-west of Sydney - had leveled off at 5000 feet.

The pilot noticed a mobile phone interference signal in his headphones, according to an incident report lodged with the Australian Transport Safety Bureau. "The aircraft continued to its destination without further incident," the log entry says.

On another occasion in 1996, a Boeing 767 pitched and dropped 120 meters before pilots recovered control. A passenger using an electronic dictionary was asked to turn it off, and the plane's systems returned to normal.

On more than one occasion, laptop computers have been blamed for changing an aircraft's internal cabin pressure.

Pilots routinely ask for portable devices to be switched off during take-off and landing. because they are too busy to deal with problems with interference. But, once in the air, when passengers are allowed to switch devices on, pilots have had to contend with a range of bewildering malfunctions.

The incidents, logged in an Australian Transport Safety Bureau database, have been collated for the first time and detailed in the latest edition of Flight Safety Australia, published by the Civil Aviation Safety Authority.

Perhaps most worrying of all, the devices often cause autopilot malfunctions, which have resulted in planes climbing, oscillating, or disengaging from the autopilot system altogether.

CASA wants to ban the use of mobile phones on all flights and prohibit the use of laptop computers, video cameras and electronic games during take-offs and landings.

CASA spokesman Peter Gibson said the level of interference was manageable but any increase would require more serious consideration. "None of these [incidents] led to anything life-threatening . . . but we have this issue constantly under review," he said. "The thing we're relying on at the moment is the common sense of passengers not to use mobiles, transmitters and other devices when they're told not to, and the vigilance of the cabin crew."

Laurie Cox, a spokesman for the Australian Federation of Air Pilots, said more research was needed into the effect of electronic devices.

"You've got to ask, do you want to get there, or do you want to use your laptop?"