Autorotation is a condition of helicopter flight during which the main rotor of a helicopter is driven only by aerodynamic forces with no power from the engine. It is a manoeuvre where the engine is disengaged from the main rotor system and the rotor blades are driven solely by the upward flow of air through the rotor.

During the final stages of the autorotation the Pilot must perform the manoeuvre called "Flare". The flare has the benefit of both reducing forward speed and increasing RRPM during the flare, which will increase the stored energy in the rotor, necessary to cushion the touchdown. The additional lift created during the flare reduces the rate of descent.

Every autorotational flare will be different depending on the existing wind conditions, airspeed, density altitude, the specific make and model of helicopter, and the rotorcraft gross weight.

Care must be taken in the execution of the flare so that the cyclic control is neither moved rearward so abruptly that it causes the helicopter to climb nor moved so slowly that it does not arrest the descent, which may allow the helicopter to settle so rapidly that the tail rotor strikes the ground. Extreme caution should be used to avoid an excessive nose-high and tail-low attitude below 10 ft.

When performing an autorotation in a mountainous area and in order to avoid hitting the tail rotor on the slope during the flare, the pilot must land with the helicopter on the upslope without any yawing.