曝光台 注意防骗
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ground (or runway) ahead and slightly to the side. Proper
depth perception is a factor in a successful roundout, but the
visual cues used most are those related to changes in runway or
terrain perspective and to changes in the size of familiar objects
near the landing area such as fences, bushes, trees, hangars,
and even sod or runway texture. The pilot should direct central
vision at a shallow downward angle of 10° to 15° toward the
runway as the roundout is initiated. [Figure 11-10]
Maintaining the same viewing angle causes the point of
visual interception with the runway to move progressively
rearward toward the pilot as the aircraft loses altitude. This is
an important visual cue in assessing the rate of altitude loss.
11-7
25
10° to 15°
Figure 11-10. To obtain necessary visual cues, the pilot should look toward the runway at a shallow angle.
Figure 11-11. Maintaining speed from final approach in the center
of the runway at about 20 feet above the runway.
Figure 11-12. Starting the roundout at about 10 to 15 feet above
the runway surface.
Conversely, forward movement of the visual interception
point indicates an increase in altitude and would mean
that the pitch angle was increased too rapidly resulting in
an over roundout. The following are also used to judge
when the wheels are just a few inches above the runway:
location of the visual interception point in conjunction with
assessment of fl ow velocity of nearby off-runway terrain,
and the similarity in appearance of height above the runway
ahead of the aircraft to the way it looked when the aircraft
was taxied prior to takeoff.
A common error during the roundout is rounding out too much
and too fast. This error can easily be avoided by gradually
increasing the AOA with a controlled descent until the wheels
are one inch above the surface and never climbing during a
roundout with a gradual and controlled roundout.
Touchdown
After a controlled roundout, the touchdown is the gentle
settling of the aircraft onto the landing surface. For calm
air conditions, the roundout can be made with the engine
idling, and touchdown can be made at minimum controllable
airspeed so that the aircraft touches down on the main gear
at the approximate stalling speed. As the aircraft settles, the
proper landing attitude is attained by application of whatever
control bar forward pressure is necessary. In calm wind
conditions, the goal is to round out smoothly and have the
control bar touch the front tube as the back wheels touch the
ground. [Figures 11-11 through 11-14] Once the rear wheel
settles to the surface, the nosewheel settles to the ground. The
control bar should be pulled all the way back to eliminate
the possibility of lifting off the ground because of a wind
gust. Pulling the nose down completely can also be used for
aerodynamic braking if needed.
After-Landing Roll
The landing process must never be considered complete
until the aircraft decelerates to normal taxi speed during the
landing roll or has been brought to a complete stop when clear
of the landing area. Many accidents have occurred as a result
of pilots abandoning their vigilance and positive control after
getting the aircraft on the ground.
11-8
Figure 11-13. Continuing the roundout as speed bleeds off and the
WSC back wheels are inches above the runway.
Figure 11-15. WSC aircraft follows the taxi line to exit the runway
while slowing the aircraft and maintaining control of the wing.
Figure 11-14. Completing the roundout with the control bar full
forward and the back wheels settling to the runway.
The pilot must make only slight turns to maintain direction
until the WSC has slowed to taxiing speed. An abrupt turn
at high speed could possibly lift a rear wheel, roll the WSC
over, or force the wingtip to the ground. The WSC must slow
to taxing speed before before any sharp turn can be made to
exit the runway.
The brakes of an aircraft serve the same primary purpose as
the brakes of an automobile—to reduce speed on the ground.
Maximum brake effectiveness is just short of the skid point.
If the brakes are applied so hard that skidding takes place,
braking becomes ineffective. Skidding can be stopped by
releasing the brake pressure. Also, braking effectiveness is
not enhanced by alternately applying and reapplying brake
pressure. The brakes should be applied fi rmly and smoothly
as necessary.
WSC aircraft have nosewheel or rear wheel braking systems.
For nosewheel systems, if braking is required right away, the
nose should be lowered so the nosewheel touches the ground
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Weight-Shift Control Aircraft Flying Handbook(117)
