Flap extension has a definite effect on the airplane’s pitch  behavior. The increased camber from flap deflection  produces lift primarily on the rear portion of the wing. This  produces a nose-down pitching moment; however, the change  in tail loads from the downwash deflected by the flaps over  the horizontal tail has a significant influence on the pitching  moment. Consequently, pitch behavior depends on the design  features of the particular airplane. flap setting, and one wind condition. A change in any one of  these variables requires an appropriate coordinated change  in the other controllable variables. For example, if the pitch  attitude is raised too high without an increase of power, the  airplane settles very rapidly and touches down short of the  desired spot. For this reason, never try to stretch a glide by  applying back-elevator pressure alone to reach the desired  landing spot. This shortens the gliding distance if power is  not added simultaneously. The proper angle of descent and  airspeed is maintained by coordinating pitch attitude changes  and power changes. Flap deflection of up to 15° primarily produces lift with  minimal drag. The airplane has a tendency to balloon up with  initial flap deflection because of the lift increase. The nose- down pitching moment, however, tends to offset the balloon.  Flap deflection beyond 15° produces a large increase in drag.  Also, deflection beyond 15° produces a significant nose-up  pitching moment in high-wing airplanes because the resulting  downwash increases the airflow over the horizontal tail. The time of flap extension and the degree of deflection  are related. Large flap deflections at one single point in  the landing pattern produce large lift changes that require  significant pitch and power changes in order to maintain  airspeed and descent angle. Consequently, there is an  advantage to extending flaps in increments while in the  landing pattern. Incremental deflection of flaps on downwind,  base leg, and final approach allow smaller adjustments of  pitch and power compared to extension of full flaps all at  one time. The objective of a good, stabilized final approach is to  descend at an angle and airspeed that permits the airplane to  reach the desired touchdown point at an airspeed that results  in minimum floating just before touchdown; in essence, a  semi-stalled condition. To accomplish this, it is essential  that both the descent angle and the airspeed be accurately  controlled. Since on a normal approach the power setting is  not fixed as in a power-off approach, the power and pitch  attitude are adjusted simultaneously as necessary to control  the airspeed and the descent angle, or to attain the desired  altitudes along the approach path. By lowering the nose and  reducing power to keep approach airspeed constant, a descent  at a higher rate can be made to correct for being too high in  the approach. This is one reason for performing approaches  with partial power; if the approach is too high, merely lower  the nose and reduce the power. When the approach is too  low, add power and raise the nose. The lift/drag factors are varied by the pilot to adjust the descent  through the use of landing flaps.  [Figures 8-3  and  8-4]  Flap  extension during landings provides several advantages by:  When the flaps are lowered, the airspeed decreases unless  the power is increased or the pitch attitude lowered. On final  approach, the pilot must estimate where the airplane lands  Figure 8-3.  Effect of flaps on the landing point. 8-4 34 No flaps Half flaps F ull flaps with: constant airspeed constant power • Producing greater lift and permitting lower landing  speed,  • Producing greater drag, permitting a steeper descent  angle without airspeed increase, and  • Reducing the length of the landing roll.  Use of Flaps