TABLE OF CONTENTS The airplane's stalling speed is one of the most important parameters obtained in flight test, since most other criteria are based upon some multiple of stalling speed. Therefore, stalling speed should be determined early in the flight test program. It is the next item to be determined after the pitot-static system has been calibrated. Stalling speed is difficult to determine because the position error is hard to define at high angles of attack and changes rapidly in that region.
One of the difficulties in determining stalling speed is defining when the stall occurs. Airplane designers and aerodynamicists define the stalling speed as the speed at which the maximum lift coefficient, C L max, occurs. However, the various FAA regulations and the military specifications have different definitions. This difference in definition of the stalling speed has led to some controversies during "off-the-shelf" buys of civil certified aircraft by the U.S. military.
The FAA has several definitions for stalling speed depending upon which certification regulation applies. This also has led to some controversies even within the FAA organization.
CAR 3.82 Definition of Stalling Speeds states:
V S 0 denotes the true indicated stalling speed, if obtainable, or the minimum steady flight speed at which the airplane is controllable, in mph, with:
engines idling, throttles closed (or no more than sufficient power for zero thrust),
propellers in a position normally used for takeoff,
landing gear extended,
