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
Suddenly increasing the angle of attack and stalling the
airplane during a roundout is a dangerous situation
since it may cause the airplane to land extremely hard
on the main landing gear, and then bounce back into
the air. As the airplane contacts the ground, the tail will
be forced down very rapidly by the back-elevator pressure
and by inertia acting downward on the tail.
Recovery from this situation requires prompt and
positive application of power prior to occurrence of
the stall. This may be followed by a normal landing if
sufficient runway is available—otherwise the pilot
should EXECUTE A GO-AROUND immediately.
If the roundout is late, the nosewheel may strike the
runway first, causing the nose to bounce upward. No
attempt should be made to force the airplane back onto
the ground; a GO-AROUND should be executed
immediately.
FLOATING DURING ROUNDOUT
If the airspeed on final approach is excessive, it will
usually result in the airplane floating. [Figure 8-34]
Before touchdown can be made, the airplane may be
well past the desired landing point and the available
runway may be insufficient. When diving an airplane
on final approach to land at the proper point, there will
be an appreciable increase in airspeed. The proper
touchdown attitude cannot be established without producing
an excessive angle of attack and lift. This will
cause the airplane to gain altitude or balloon.
Any time the airplane floats, judgment of speed,
height, and rate of sink must be especially acute. The
pilot must smoothly and gradually adjust the pitch attitude
as the airplane decelerates to touchdown speed
and starts to settle, so the proper landing attitude is
attained at the moment of touchdown. The slightest
Figure 8-33. Rounding out too high.
Figure 8-34. Floating during roundout.
Ch 08.qxd 5/7/04 8:08 AM Page 8-29
PDF Create! 5 Trial
www.nuance.com
error in judgment and timing will result in either ballooning
or bouncing.
The recovery from floating will depend on the amount
of floating and the effect of any crosswind, as well as
the amount of runway remaining. Since prolonged
floating utilizes considerable runway length, it should
be avoided especially on short runways or in strong
crosswinds. If a landing cannot be made on the first
third of the runway, or the airplane drifts sideways, the
pilot should EXECUTE A GO-AROUND.
BALLOONING DURING ROUNDOUT
If the pilot misjudges the rate of sink during a landing
and thinks the airplane is descending faster than it
should, there is a tendency to increase the pitch attitude
and angle of attack too rapidly. This not only
stops the descent, but actually starts the airplane
climbing. This climbing during the roundout is
known as ballooning. [Figure 8-35] Ballooning can
be dangerous because the height above the ground is
increasing and the airplane may be rapidly
approaching a stalled condition. The altitude gained
in each instance will depend on the airspeed or the
speed with which the pitch attitude is increased.
When ballooning is slight, a constant landing attitude
should be held and the airplane allowed to gradually
decelerate and settle onto the runway. Depending on
the severity of ballooning, the use of throttle may be
helpful in cushioning the landing. By adding power,
thrust can be increased to keep the airspeed from
decelerating too rapidly and the wings from suddenly
losing lift, but throttle must be closed immediately
after touchdown. Remember that torque will be created
as power is applied; therefore, it will be necessary
to use rudder pressure to keep the airplane straight as it
settles onto the runway.
When ballooning is excessive, it is best to EXECUTE
A GO-AROUND IMMEDIATELY; DO NOT
ATTEMPT TO SALVAGE THE LANDING. Power
must be applied before the airplane enters a stalled
condition.
The pilot must be extremely cautious of ballooning
when there is a crosswind present because the crosswind
correction may be inadvertently released or it
may become inadequate. Because of the lower airspeed
after ballooning, the crosswind affects the airplane
more. Consequently, the wing will have to be lowered
even further to compensate for the increased drift. It
is imperative that the pilot makes certain that the
appropriate wing is down and that directional control
is maintained with opposite rudder. If there is any
doubt, or the airplane starts to drift, EXECUTE A
GO-AROUND.
BOUNCING DURING TOUCHDOWN
When the airplane contacts the ground with a sharp
impact as the result of an improper attitude or an
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
AIRPLANE FLYING HANDBOOK 飞机飞行手册上(100)
