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.