Falling leaf

A falling leaf (also called a rudder stall or oscillation stall) is an aerobatic maneuver in which an aircraft performs a wings-level stall (the airplane stops flying and starts falling) which begins to induce a spin. This spin is countered with the rudder, which begins a spin in the opposite direction that must be countered with rudder, and the process is repeated as many times as the pilot determines. During the maneuver, the plane resembles a leaf falling from the sky; first slipping to one side, stopping, and then slipping to the other direction; continuing a side-to-side motion as it drifts toward the ground.

A falling leaf is a controlled stall performed in a fixed-wing aircraft. The maneuver is performed by purposely stalling the airplane and then carefully using the rudder to try to hold the aircraft on a steady course. The falling leaf consists of a constant rotation about the yaw axis while continually changing the direction. This is opposed to a flat spin, where the aircraft constantly rotates around its yaw axis in only one direction, similar to a Frisbee. The falling leaf is sometimes described as carefully "walking" the aircraft while stalled. The maneuver is typically performed mostly with the rudder, trimming with the elevator but keeping the ailerons neutral.

With the exception of landing, plus a few exotic maneuvers, stalling an aircraft is typically avoided in most maneuvers, both because the plane is no longer flying normally, making the control surfaces sloppy and sluggish to react, and also because the aircraft is balanced on the edge of losing control. If the pilot can maintain a level attitude (nose position in relation to the horizon) and keep the wings level, the plane should theoretically float downward at its terminal velocity, which is partially determined by the shape of the plane in the direction of the relative wind. However, the slightest bit of variation in any of a number of factors, such as control surface inputs or air turbulence, will generally result in the aircraft beginning a rotation around both the yaw and roll axes, referred to as "incipient spin." The rotation may be self-induced, called autorotation, or, in maneuvers like the falling leaf, the rotation is pilot-induced by using the rudder.

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