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U.S CIVIL AERONAUTICS AUTHORITY    180

off an even keel laterally. This is particularly true during power stalls.

2. It is very important that the wings be perfectly level laterally both at the moment just prior to and the stall and at the moment the stall actually occurs. Any deviation from this may result in loss of control beyond any possibility of regaining it without relaxation of the elevators.

The student must be cautioned against ever allowing, or intentionally performing a "whip stall" during the practice of these stalls. A "whip stall," or "tail slide" as it is sometimes called, imposes loads and stresses on the tail section and the control system that they are not designed to withstand. Such a maneuver can easily result in a structural fail.

When the proper type of stall is performed, the airplane will definitely "sink" but will not slide back on its tail prior to the nose falling. With the stick held all the way back, as soon as minimum flying speed is regained the nose will start to return to level. During the ensuing period, until the nose returns to the level where the elevators are to be relaxed, the pilot must exhibit extremely fine anticipation and accurate control touch if the airplane is to be held level laterally. 

This maneuver is designed to teach and develop the following:

1. Accurate sensing of the impending actions of the ship.

2. The ability to make automatic or reflex corrections accurately in order to anticipate and prevent the development of undesirable tendencies of the airplane at critical speeds. 

3. The use of the rudder rather than the ailerons, to keep the wings level while in stalled attitudes.

4. The results of tendencies of an airplane in a full stall if alert attention is not continuously directed to it.

5. The ability to recognize the approach and presence of a stall even while the nose is down and some control is being maintained.


PRECISION SPINS

A precision spin is more of an acrobatic maneuver than the elementary spin described previously. While it is the same maneuver in its essentials, the addition of trained entry technique to enable precise execution and a difference of recovery technique to enable accurate and controlled recovery, require a further development of understanding of control action, a knowledge of the characteristics of the airplane, and perfect orientation under difficult circumstances, all of which are valuable additions to the technique and knowledge of the student. 

The entry technique will vary greatly, being dependent on the individual characteristics of the particular aircraft being used. However, the student should be required to be fully in the spin in a quarter of a turn or less. Skidding spirals, or aimless gyrations of a half to three quarters of a turn, have no place in the precision spin. with some airplanes it may be necessary to use a blast of the throttle to start the rotation in order to meet this requirement. 

During recovery the spin must be stopped exactly at any predetermined number of turns or fraction thereof. Usually spins are given and required by half and full turns, that is, one-half turn, one