Attention Passengers, This Is Your Captain Freaking

Sydney Morning Herald

Friday May 25, 2001

Darren Goodsir

Feel like the plane is suddenly falling from the sky, or worried about shakes or sudden mid-air turbulence? It may be your pilot is suffering from a serious visual illusion, where all sense of balance is lost and instinctive decisions are wrongly made sometimes sending the plane into graveyard spirals and suicide spins.

Tomorrow, aviation and medical experts will gather in Melbourne to talk about the phenomenon that affects up to 95 per cent of pilots.

An assistant director at the Civil Aviation Safety Authority, Mr Mike Smith, said ``powerful sensory illusions" often took hold of pilots, especially at night, in clouds or inclement weather.

``Sometimes pilots experience a general feeling of disorientation or a sensation of tumbling or rotating when they're not," Mr Smith said.

He said the phenomenon linked to an imbalance caused by the otolith organ in the inner ear affected even experienced pilots, and required them to fight against their natural tendencies. Up to two light aircraft accidents each year could be linked to the problem.

It commonly occurs during take-off in darkness when the sudden acceleration pushes the pilot into the back of the seat, making the pilot feel as if the plane is heading into the sky at a steeper trajectory.

This tempts the pilot to over-compensate with the instruments, and the plane can then crash off the end of the runway.

Indeed, this ``false climb" illusion was first identified after a series of night crashes during training flights in Britain in World War II.

A University of Illinois study of 20 student pilots who flew in simulated weather found that, in clouds when all sense of direction was lost all subjects failed to be able to control their planes.

It took an average of 178 seconds before the simulators took on a roller-coaster pattern and crashed.

Mr Smith recalled an incident he had years ago at Moruya airport, on the NSW South Coast, where he took off in darkness and then spotted a light.

Thinking it was another aircraft in the distance, he started to level off to its height.

However, the light was from a fishing trawler the imbalance of the moment and his reactions on the instrument panel almost sent him in to the ocean.

``It was able to be corrected, but it was a very powerful and uncomfortable experience," he said.