Table of Contents
Flight at Less than Cruise Airspeeds
Flight at Minimum Controllable Airspeed
Recognition of Stalls
Fundamentals of Stall Recovery
Use of Ailerons/Rudder in Stall Recovery
Approaches to Stalls (Imminent Stalls)—Power-On or Power-Off
Full Stalls Power-Off
Full Stalls Power-On
Elevator Trim Stall
Weight and Balance Requirements
RECOGNITION OF STALLS
Pilots must recognize the flight conditions that are
conducive to stalls and know how to apply the
necessary corrective action. They should learn to
recognize an approaching stall by sight, sound, and
feel. The following cues may be useful in recognizing
the approaching stall.
- Vision is useful in detecting a stall condition by noting the attitude of the airplane. This sense can only be relied on when the stall is the result of an unusual attitude of the airplane. Since the airplane can also be stalled from a normal attitude, vision
- in this instance would be of little help in detecting the approaching stall.
- Hearing is also helpful in sensing a stall condition. In the case of fixed-pitch propeller airplanes in a power-on condition, a change in sound due to loss of revolutions per minute (r.p.m.) is particularly noticeable. The lessening of the noise made by the air flowing along the airplane structure as airspeed decreases is also quite noticeable, and when the stall is almost complete, vibration and incident noises often increase greatly.
- Kinesthesia, or the sensing of changes in direction or speed of motion, is probably the most important and the best indicator to the trained and experienced pilot. If this sensitivity is properly developed, it will warn of a decrease in speed or the beginning of a settling or mushing of the airplane.
- Feel is an important sense in recognizing the onset of a stall. The feeling of control pressures is very important. As speed is reduced, the resistance to pressures on the controls becomes progressively less. Pressures exerted on the controls tend to become movements of the control surfaces. The lag between these movements and the response of the airplane becomes greater, until in a complete stall all controls can be moved with almost no resistance, and with little immediate effect on the airplane. Just before the stall occurs, buffeting, uncontrollable pitching, or vibrations may begin.
Several types of stall warning indicators have been
developed to warn pilots of an approaching stall. The
use of such indicators is valuable and desirable, but the
reason for practicing stalls is to learn to recognize stalls
without the benefit of warning devices.
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