曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
as required for the height above the landing spot. Refer to the
steep approach section earlier in this chapter.
Slow Final Approach
When the aircraft is fl own at slower-than-normal airspeed
on the fi nal approach, pilot determination of the rate of sink
(descent) and the height of roundout is diffi cult. During an
excessively slow approach, the wing is operating near the
critical AOA and, depending on the pitch attitude changes
and control usage, the aircraft may stall or sink rapidly and
contact the ground with a hard impact.
11-28
34
Add power
Hold altitude
1
Intercept normal glidepath
Reduce power smoothly
Resume normal approach
2
Normal Approach Path
Wrong (Approach Too Low)
Figure 11-36. Right and wrong methods of correction for low final approach.
Whenever a low-speed approach is noted, the pilot should
apply power and accelerate the aircraft to reduce the sink rate
to prevent a stall. This should be done while still at a high
enough altitude to reestablish the correct approach airspeed
and attitude. If too slow and too low, it is best to execute a
go-around.
Use of Power
Power can be used if required during the approach and
roundout to compensate for errors in judgment. The pilot
should be ready to use the foot throttle while managing the
energy throughout the landing, utilizing energy management
procedures for the current landing conditions. Power can be
added to reduce the descent rate if needed; thus, the descent
can be slowed to an acceptable rate. After the aircraft has
touched down, it is necessary to close the throttle to remove
additional thrust and lift allowing the aircraft to stay on the
ground.
High Roundout
Sometimes when the aircraft appears to stop moving downward
temporarily, the roundout has been made too rapidly and the
aircraft is fl ying level, too high and too slow above the runway.
Continuing the roundout would further reduce the airspeed,
resulting in an increase in AOA to the critical angle. This
would result in the aircraft stalling and dropping hard onto
the runway. To prevent the hard drop, pitch attitude should
be reduced slightly to increase speed to approach speed while
throttle is added to maintain altitude. After speed has been
increased and altitude maintained, the throttle and speed can
both be reduced smoothly and gradually for a gradual descent
with a normal roundout and touchdown.
Although speed is needed after the high roundout is noticed in
order to be corrected, the power application must be enough to
remain level and not initially descend as the speed is increased.
Energy management profi ciency is critical. If too little throttle
is added, the momentary decrease in lift that would result
from lowering the nose and decreasing the AOA may be
so great that the aircraft might contact the ground with the
nosewheel fi rst, which could then collapse. As for all landing
maneuvers that are questionable and the outcome is uncertain,
it is recommended that a go-around be executed.
Late or Rapid Roundout
Starting the roundout too late or pushing the control forward
too rapidly to prevent the aircraft from touching down
prematurely balloons the aircraft up above the runway.
Suddenly increasing the AOA and stalling the aircraft during
a roundout is a dangerous situation since it may cause the
aircraft to land extremely hard on the main landing gear and
then bounce back into the air.
Recovery from this situation requires prompt and positive
application of power and a lowering of the nose to increase
speed prior to occurrence of the stall. This may be followed
by a normal landing, if suffi cient runway is available, similar
to the high roundout discussed above—otherwise the pilot
should immediately execute a go-around.
Floating During Roundout
If the airspeed on fi nal approach is excessive, it usually results
in the aircraft fl oating in ground effect. This is not a problem
if there is plenty of runway and if the pilot fl oats with the
wheels just inches above the surface. Simply maintain this
position inches above the runway, slowly rounding out as
required until the speed bleeds off for a normal touchdown.
If conditions are turbulent, the nose can be lowered gradually
and the aircraft fl own onto the ground, as discussed earlier
in the landing in turbulence procedures.
If the aircraft is well past the desired landing point and
the available runway is insuffi cient, perform a go-around
immediately.
11-29
Ballooning During Roundout
If the pilot misjudges the rate of sink during a landing and
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
Weight-Shift Control Aircraft Flying Handbook(131)
