For instance, at 4300 lbs, flaps down, maintaining 20 units, your airspeed will be about 85 KIAS
and your stall speed about 55 KIAS. 85 KIAS - 35% of 85 = 55 KIAS. Or, for a 3500 lb.
airplane, airspeed would be about 77 KIAS and stall speed about 50 KIAS. Again, 77 KIAS -
35% of 77 = 50 KIAS.
As you can see, flying an approach at optimum AOA gives you an adequate safety margin
(approach airspeed above stall speed), while keeping your approach and landing speed low.
AOA approaches will normally be flown after one or more touch-and-go landings.
After a touch-and-go, climb out at 90 KIAS (leave the flaps down) for full-flap AOA
or 100 KIAS (flaps up) for no-flap AOA. Climb to pattern altitude.
Your instructor will judge interval for the crosswind turn. During the turn notify
other aircraft in the pattern, if performing a full-flap AOA, that you will be
conducting an AOA approach.
Level off at pattern altitude and 100 KIAS by reducing power to 650-700 ft-lbs.
(approx. 550 ft-lbs. NF).
Approaching the upwind numbers, reduce power to 300 ftlbs. and slow to 20 units
AOA (approximately 80 KIAS FF/95 KIAS NF). If flaps are down, a deceleration to
20 units AOA is all that is required. If flaps are up, reduce power to 300 ft-lbs. and
lower the flaps (check airspeed below 120 KIAS) if performing a FF approach. Slow
to 20 units AOA. Carefully adjust power to approximately 500 ft-lbs. to maintain
pattern altitude and adjust nose attitude to maintain optimum AOA; 20 units on the
gauge and an amber donut, "O" on the indexer. Maintain 20 units and a ¾ wingtip
distance on downwind.
Perform the Landing Checklist prior to abeam position.
Abeam the intended point of landing reduce power to approximately 300 ftlbs. (275
ft-lbs. NF), lower the nose slightly to maintain 20 units and commence the turn at the
180º position. Your pattern over the ground should be the same as in previous
landings, but your airspeed will be constant at about 80 KIAS (95 KIAS NF). You
will probably need less angle of bank at the lower airspeed. Using the same angle of
bank as in a normal approach would result in too tight a turn.
During the approach, scan the AOA indexer, the intended point of landing and the
altimeter. Adjust power and attitude as necessary to maintain the proper rate of
descent and 20 units. If the green "slow" chevron ("V") lights up, your AOA is
higher than optimum and your airspeed is too slow. To correct, lower the nose
slightly. The chevron points in the direction the nose needs to go. Too low a nose
12-2 ANGLE OF ATTACK APPROACHES