The ground effect is one of aviation’s more unusual principles.
It is described as the patch of air planes encounter close to the runway, just as they takeoff and land.
The ground effect occurs in the space below the height of an aircraft’s wingspan.
It’s caused by the compression of air between the wing and the tarmac, which forms a cushion of air to give the impression of floating.
When aircraft come into land, they hit ground effect about 15 seconds before touch down.
As they float on this cushion of air, they have in some ways already landed.
But if pilots aren’t trained in how to respond to ground effect, the phenomenon can prevent the plane from touching down by causing it to float along the runway.
Similarly when a plane takes off, it can float in ground effect as it gathers enough speed to ascend.
But it can also prove dangerous, if the aircraft isn’t flying quick enough and can’t climb out of the ground effect.
Commercial pilot Tim Morgan explained: “An airplane can fly in ground effect in situations where it could not fly in normal air. This can lead to accidents when the pilot lifts off too early and flies in ground effect.
“He may be lulled into believing the aircraft can fly, but find himself unable to climb out of ground effect, resulting potentially in a collision with obstacles past the runway.”
Airline pilot Mark Vanhoenacker said the effect is one of the most remarkable things a pilot can experience.
He told the Telegraph: “Imagine that as you get closer to the ground, the air below the wings can no longer ‘get out of the way’ in time.
“Pilots must be prepared to lower the nose a bit in order to maintain our rate of descent as we enter it.