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How a plane flies

A view of an airliner's wings as it comes in to landA view of an airliner's wings as it comes in to landHow does a heavy aeroplane fly through the air? It relies on its engines to drive it forward at speed and its wings to provide lift. To steer, the aeroplane's control surfaces (rudder, elevators and ailerons) on the wings and tail are adjusted, which change the airflow around the plane. On many planes, the wings are angled slightly upwards (called a dihedral), which helps the plane to stop rolling. Ailerons, which are like horizontal rudders attached to the rear (trailing) edges of the wings, constantly adjust the roll as the plane flies forward, keeping it level.

How lift is producedHow lift is produced


As an aeroplane moves forwards, air hitting the leading (front) edge of the wing separates above and below the wing. Because of the wing's aerofoil shape—curved more on its upper side than its lower side—the air that flows over it is faster than that flowing under it. This creates lower air pressure above the wing than beneath it. The difference in pressure pushes the wing upwards with a force called lift.

The amount of lift can be raised by increasing both the speed of the plane and the angle of attack, the angle at which the leading (front) edge of the wing strikes the air. At lower speeds, the pilot maintains lift by raising the nose of the plane to increase the angle of attack. But if the angle becomes too great, air cannot flow smoothly over the top of the wing and lift is lost. This is called a stall.

Air is the safest way to travel long distances. There are fewer deaths per billion kilometres travelled—just 0.05—than by any other means of transport. Motorbikes are the most dangerous mode of transport, with 109 deaths per billion kilometres.

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