Aerodynamic Principles
Out-of-Control Flight
An aircraft that has a large negative IYMP will tend to spin in a flatter nose attitude than an aircraft that is
neutrally loaded or wing-loaded. The inertial moments on the spinning aircraft will pull the nose toward the
horizon (Figure 7). As you will see later, the mass distribution will also significantly affect spin recovery
requirements.
DIRECTION
OF SPIN
Fly Wheel
Effect
Nose Rises Due to
Fly Wheel Effect
SPIN AXIS
Figure 7: PITCHUP DUE TO INERTIAL COUPLING
STALL
(This is not an all inclusive definition.) That AOA beyond which a further increase in AOA will produce a
decrease in lift.
(9-98) Original
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