minimum speeds. By definition, the term “flight at minimum  controllable airspeed” means a speed at which any further  increase in AOA or load factor causes an immediate stall.  Pilots must develop an awareness of the particular glider  flight characteristics in order to recognize and avoid stalls  that may inadvertently occur during the low airspeeds used  in takeoffs, climbs, thermaling, and approaches to landing. The ball in the slip/skid indicator also indicates slips and  skids. When using this instrument for coordination, apply  rudder pressure on the side that the ball is offset (step on  the ball). Correction for uncoordinated condition should be  accomplished by using appropriate rudder and aileron control  pressures simultaneously to coordinate the glider. Soaring flight requires competence in steep turns. In  thermalling flight, small-radius turns are often necessary to  keep the glider in or near the core of the thermal updraft where  lift is usually strongest and rapid climbs are possible. At any  given airspeed, increasing the angle of bank decreases the  radius of the turn and increases the rate of turn. The radius  of a turn at any given bank angle varies directly with the  square of the airspeed at which the turn is made; therefore,  the lower the airspeed is, the smaller the turn radius is. To  keep the radius of turn small, it is necessary to bank steeply  while maintaining an appropriate airspeed, such as minimum  sink or best glide speed. The pilot must be aware that as the  bank angle increases, the stall speed increases. The objective of maneuvering at minimum controllable  airspeed 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 low airspeeds.  Maneuvering at minimum controllable airspeed should be  performed using outside visual reference. It is important that  pilots form the habit of frequently referencing the pitch attitude  of the glider for airspeed control while flying at low speeds. The maneuver is started from either best glide speed or  minimum sink speed. The pitch attitude is smoothly and  gradually increased. While the glider is losing airspeed,  the position of the nose in relation to the horizon should be  noted and should be adjusted as necessary until the minimum  controllable airspeed is established. During these changing  flight conditions, it is important to retrim the glider, as  necessary, to compensate for changes in control pressures.  Back pressure that is excessive or too aggressive on the  elevator control may result in an abrupt increase in pitch  attitude and a rapid decrease in airspeed, which lead to a  higher AOA and a possible stall. When the desired pitch  attitude and airspeed have been established, it is important  to continually cross-check the pitch attitude on the horizon  and the airspeed indicator to ensure accurate control is being  maintained. Before starting the steep turn, the pilot should ensure that the  area is clear of other traffic since the rate of turn is quite rapid.  After establishing the appropriate airspeed, the glider should  be smoothly rolled into a coordinated steep turn with at least  45° of bank. The pilot should use outside visual reference  to establish and maintain the desired bank angle. If the pilot  does not add back pressure to maintain the desired airspeed  after the bank is established, the glider has a tendency to enter  a spiral. To counteract the overbanking tendency caused by  the steep turn, the pilot should apply top aileron pressure.  Because the top aileron pressure pulls the nose away from  the direction of the turn, the pilot also must apply bottom  rudder pressure. A coordinated (no slip or skid) steep turn  requires back pressure on the elevator for airspeed control, top  aileron pressure for bank control, and bottom rudder pressure  to streamline the fuselage with the flightpath. Common errors during steep turns include: When minimum controllable airspeed is established in  straight flight, turns should be practiced to determine  the glider’s controllability characteristics at this selected  airspeed. During the turns, the pitch attitude may need to  be decreased in order to maintain the airspeed. If a steep  turn is encountered, and the pitch attitude is not decreased,  the increase in load factor may result in a stall. A stall may  also occur as a result of abrupt or rough control movements  resulting in momentary increases in load factor. Abruptly  raising the flaps during minimum controllable airspeed results  in sudden loss of lift and possibly causing a stall. Minimum controllable airspeed should also be practiced  with extended spoilers/dive brakes. This provides additional  understanding of the changes in pitch attitude caused by the  increase in drag from the spoilers/dive brakes. Actual minimum controllable airspeed depends upon various  conditions, such as the gross weight and CG location of the  Maneuvering during slow flight demonstrates the flight  characteristics and degree of controllability of a glider at  7-31 •  Failure to clear turn. •  Uncoordinated use of controls. •  Loss of orientation. •  Failure to maintain airspeed within tolerance. •  Unintentional stall or spin. •  Excessive deviation from desired heading during  roll-out. Maneuvering at Minimum Controllable Airspeed Steep Turns