Load factor 2 G’s Centrifugal force 1.73 G’s Gravity 1G 6 0 ° 2MIN. D.C. ELEC. L R N O P I T C H $_{I}$N $_{F}$O R M A T $_{I}$O N To maintain aircraft control when faced with these or other  contributing factors, the pilot must be aware of situations where  LOC-I can occur, recognize when an airplane is approaching  a stall, has stalled, or is in an upset condition, and understand  and execute the correct procedures to recover the aircraft.  The term “upset” was formally introduced by an industry  work group in 2004 in the “Pilot Guide to Airplane Upset  Recovery,” which is one part of the “Airplane Upset  Recovery Training Aid.” The working group was primarily  focused on large transport airplanes and sought to come up  with one term to describe an “unusual attitude” or “loss of  control,” for example, and to generally describe specific  parameters as part of its definition. Consistent with the Guide,  the FAA has defined an upset as an event that unintentionally  exceeds the parameters normally experienced in flight or  training. These parameters are:  is not slipping or skidding. A correction should be made by  applying rudder pressure on the side toward which one feels  a leaning sensation. This will be the same side to which the  ball in the slip/skid indicator has slewed (i.e., the old saying  “step on the ball”).  The reference to inappropriate airspeeds describes a number  of undesired aircraft states, including stalls. However, stalls  are directly related to angle of attack (AOA), not airspeed. To develop the crucial skills to prevent LOC-I, a pilot must  receive upset prevention and recovery training (UPRT), which  should include: slow flight, stalls, spins, and unusual attitudes. Upset training has placed more focus on prevention—  understanding what can lead to an upset so a pilot does not  find himself or herself in such a situation. If an upset does  occur, however, upset training also reinforces proper recovery  techniques. A more detailed discussion of UPRT to include  its core concepts, what the training should include, and what  airplanes or kinds of simulation can be used for the training  can be found later in this chapter. The angle of attack (AOA) is the angle at which the chord of  the wing meets the relative wind. The chord is a straight line  from the leading edge to the trailing edge. At low angles of  attack, the airflow over the top of the wing flows smoothly  and produces lift with a relatively small amount of drag. As  the AOA increases, lift as well as drag increases; however,  above a wing’s critical AOA, the flow of air separates from  the upper surface and backfills, burbles and eddies, which  reduces lift and increases drag. This condition is a stall,  which can lead to loss of control if the AOA is not reduced.  It is important for the pilot to understand that a stall is the result  of exceeding the critical AOA, not of insufficient airspeed.  The term “stalling speed” can be misleading, as this speed is  often discussed when assuming 1G flight at a particular weight  and configuration. Increased load factor directly affects  stall speed (as well as do other factors such as gross weight,  center of gravity, and flap setting). Therefore, it is possible  to stall the wing at any airspeed, at any flight attitude, and at  any power setting. For example, if a pilot maintains airspeed  and rolls into a coordinated, level 60° banked turn, the load  factor is 2Gs, and the airplane will stall at a speed that is 40  percent higher than the straight-and-level stall speed. In that  2G level turn, the pilot has to increase AOA to increase the  lift required to maintain altitude. At this condition, the pilot  is closer to the critical AOA than during level flight and  Coordinated flight occurs whenever the pilot is proactively  correcting for yaw effects associated with power (engine/ propeller effects), aileron inputs, how an airplane reacts when  turning, and airplane rigging. The airplane is in coordinated  flight when the airplane’s nose is yawed directly into the  relative wind and the ball is centered in the slip/skid indicator.  [Figure 4-1] A pilot should develop a sensitivity to side loads that indicate  the nose is not yawed into the relative wind, and the airplane  4-2 Coordinated Flight Angle of Attack Defining an Airplane Upset • Pitch attitude greater than 25°, nose up • Pitch attitude greater than 10°, nose down • Bank angle greater than 45° • Within the above parameters, but flying at airspeeds  inappropriate for the conditions.  Figure 4-1.  Coordinated flight in a turn.