Rolling aeroplanes

Denzel Washington in the film Flight
Picture by Getty Images (Johnston)
Date:16 February 2013 Tags:, , , ,

By: Elyse Moody

The movie Flight, released last November, stars Denzel Washington as a pilot who inverts a crashing airliner to save most of his passengers and crew. It’s a stunning sequence – but could it really happen?

Tom Aldag, director of R&D for the National Institute for Aviation Research, says that rolling a large plane to prevent a death dive makes theoretical sense. In the movie, the plane’s horizontal stabiliser is stuck – the airliner’s nose is aimed down, airflow and gravity forcing it into a death dive. Rolling the airplane over would reorient the nose: it would remain pitched down, but now “down” means up, away from Earth.

During the sequence, Washington commands his cockpit crew to deploy the speed brakes and the flaps to slow down the aircraft. Lower speeds decrease stress on the airframe, explains Russ Williams, an airline test pilot. Flaps do the same, though they’re not designed to deploy at high speeds. “I would not extend flaps until I got the plane slowed down,” Williams says. “They have a limiting speed, and if you extend them past that they can break and come off.”

Inverting a stricken airliner doesn’t fix whatever problem caused it to drop. Once the aircraft is flying the way its designers intended, it would again plummet. That means reorienting the plane close to the ground – a feat that would require a pilot with the nerves of a movie hero.

The reaction speeds required to fly this way make the scenario pure Hollywood. “If you know what you’re doing, sure, you could roll an aircraft,” Williams says. “But your timing would have to be pretty perfect.”

How to roll a plane:

Step one
An aeroplane in an uncontrolled dive needs to slow down and regain stability. The pilot can apply the speed brakes.

Step two
Inversion risks engine shutdown because fuel lines draw from the tank’s bottom. The pilot must keep wings level and aim into the wind to slow down.

Step three
Once righted, the plane would return to its uncontrolled drop, so the pilot would have to land almost immediately after returning the aircraft to its correct orientation.

Stranger than fiction: In 1955, test pilot Alvin “Tex” Johnston performed two barrel rolls during a demonstration flight of a Boeing Dash 80, the prototype of the large 707 airliner. Johnston awed witnesses, but his boss was not impressed: no one okayed the stunt and Johnston was ordered never to do it again. Twenty years later, the daring test pilot became director of the flight test department at Stanley Aviation, where he dev-eloped ejection seats.

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