Complex sentence: When the angle of attack on the wing of an aircraft, or on one wing, reaches the stalling angle, the aircraft is at risk of autorotation that will eventually develop into a spin if the pilot does not take corrective action.
Split into simpler sentences: When the angle of attack on the wing of an aircraft reaches the stalling angle the aircraft is at risk of autorotation. This will eventually develop into a spin if the pilot does not take corrective action.