or contact the manufacturer for specific limitations applicable  to that indicator type. Different airplane designs can result in different stall  characteristics. The pilot should know the stall characteristics  of the airplane being flown and the manufacturer’s  recommended recovery procedures. Factors that can affect  the stall characteristics of an airplane include its geometry,  CG, wing design, and high-lift devices. Engineering design  variations make it impossible to specifically describe the stall  characteristics for all airplanes; however, there are enough  similarities in small general aviation training-type airplanes  to offer broad guidelines.  Most training airplanes are designed so that the wings stall  progressively outward from the wing roots (where the wing  attaches to the fuselage) to the wingtips. Some wings are  Pilots in training must remember that a level-flight 1G stalling  speed is valid only:  Understanding what type of AOA indicator is installed on an  airplane, how the particular device determines AOA, what the  display is indicating and when the critical AOA is reached,  and what the appropriate response is to those indications  are all important components to AOA indicator training. It  is also encouraged to conduct in-flight training to see the  indications throughout various maneuvers, like slow flight,  stalls, takeoffs, and landings, and to practice the appropriate  responses to those indications. It is also important to note that  some items may limit the effectiveness of an AOA indicator  (e.g., calibration techniques, wing contamination, unheated  probes/vanes). Pilots flying an airplane equipped with an  AOA indicator should refer to the pilot handbook information  4-6 Figure 4-5.  A conceptual representation of an AOA indicator. It  is important to become familiar with the equipment installed in a  specific airplane. Angle of Attack Indicators  Stall Characteristics • At a particular center of gravity (CG) (typically  maximum forward CG) • At one weight (typically maximum gross weight) • In coordinated flight (slip-skid indicator centered) • In unaccelerated 1G flight • Kinesthesia—the physical sensation (sometimes  referred to as “seat of the pants” sensations) of changes  in direction or speed is an important indicator to the  trained and experienced pilot in visual flight. If this  sensitivity is properly developed, it can warn the pilot  of an impending stall.  • Hearing—as speed decreases, the pilot should notice  a change in sound made by the air flowing along the  airplane structure.  • Vision—since the airplane can be stalled in any  attitude, vision is not a foolproof indicator of  an impending stall. However, maintaining pitch  awareness is important. 10° 16° 17° A B C 2.0 1.5 1.0 0.5 -4 0 5 10 15 20 Angle of attack in degrees Coefficient of Lift (C L ) A B C A B C Learning to recognize stalls without relying on stall warning  devices is important. However, airplanes can be equipped  with AOA indicators that can provide a visual indication of  the airplane’s proximity to the critical AOA. There are several  different kinds of AOA indicators with varying methods for  calculating AOA, therefore proper installation and training on  the use of these devices is important. AOA indicators measure  several parameters simultaneously, determine the current  AOA, and provide a visual image of the proximity to the critical  AOA.  [Figure 4-5]  Some AOA indicators also provide aural  indications, which can provide awareness to a change in AOA  that is trending towards the critical AOA prior to installed stall  warning systems. It’s important to note that some indicators  take flap position into consideration, but not all do. 