Low Speed GLYPH<127> Low Power Fast Speed GLYPH<127> Higher Power Relative Wind Flightpath Relative Wind Flightpath High Kinetic Energy Low Kinetic Energy Figure 6-20. Energy management: low and high kinetic energy for level flight.  Slow Flight and Stalls  Slow Flight As discussed in chapter 2, the maintenance of lift and control  of an aircraft in slow flight requires a certain minimum  airspeed and angle of attack. This critical airspeed depends  on certain factors, such as gross weight, load factors, and  density altitude. The minimum speed below which further  controlled flight is impossible is called the stalling speed.  An important feature of pilot training is the development  of the ability to estimate and “feel” the margin of speed  above the stalling speed. Also, the ability to determine the  characteristic responses of the aircraft at different airspeeds  is of great importance to the pilot. The student pilot,  therefore, must develop this awareness in order to safely  avoid stalls and to operate an aircraft correctly and safely  at slow airspeeds. The minimum controlled airspeed maneuver demonstrates  the flight characteristics and degree of controllability of the  aircraft at its minimum flying speed. By definition, the term  “flight at minimum controllable airspeed” means a speed at  which any further increase in angle of attack or load factor  causes an immediate stall. Instruction in flight at minimum  controllable airspeed should be introduced at reduced power  settings with the airspeed sufficiently above the stall to  permit maneuvering, but close enough to the stall to sense the  characteristics of flight at very low airspeed—sloppy control,  ragged response to control inputs, diffi culty maintaining  altitude, etc. Maneuvering at minimum controllable airspeed  should be performed using both instrument indications and  outside visual reference. It is important that pilots form the  habit of frequent reference to the flight instruments, especially  the airspeed indicator, while flying at very low airspeeds.  However, the goal is to develop a “feel” for the aircraft at  very low airspeeds to avoid inadvertent stalls and to operate  the aircraft with precision. The objective of performing the minimum controlled airspeed  is to fly straight and level and make shallow level turns at  minimum controlled airspeed. To begin a minimum controlled  airspeed maneuver, the WSC is flown at trim speed straight and  level to maintain a constant altitude. The nose is then raised as  the throttle is reduced to maintain a constant altitude. As discussed in chapter 2, the nose stalls while the tips keep  flying. Therefore, the definition of stall speed of the WSC  aircraft is the speed at which the nose starts stalling. The  control bar is pushed forward and buffeting is felt on the  control bar as the root reaches the critical angle of attack.  Separation of the laminar airflow occurs, creating turbulence  that can be felt in the control bar. There is a loss of positive  roll control as the nose buffets and lowers as it loses lift. The objective of maneuvering during slow flight is to  develop the pilot’s sense of feel and ability to use the  controls correctly and to improve proficiency in performing  maneuvers that require slow airspeeds. As the speed decreases further, the pilot should note the  feel of the flight controls, pitch pressure, and diffi culty of  maintaining a straight heading with the increased side-to-side  pilot input forces required to keep the wings level. At some  point the throttle must be increased to remain level after the  WSC has slowed below it’s maximum L$_{D}$ speed. The pilot  should also note the sound of the airflow as it falls off in tone.  There is a large difference by manufacturer and model, but  the bar generally should not be touching the forward tube  at minimum controlled airspeed. For example, the control  bar would be 1 to 3 inches from the front tube at minimum  controlled airspeed.  [Figure 6-21] Slow flight is broken down into two distinct speeds:  1. V$_{X}$ and the short field descent speed that was discussed  earlier, and,  2. Minimum controlled airspeed, the slowest airspeed at  which the aircraft is capable of maintaining controlled  flight without indications of a stall—usually 2 to 3  knots above stalling speed as discussed below. 6-20