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approach and landing is not particularly difficult
or dangerous. However, there are certain factors which
must be considered in the execution of this maneuver.
A no-flap landing requires substantially more runway
than normal. The increase in required landing distance
could be as much as 50 percent.
When flying in the traffic pattern with the wing flaps
retracted, the airplane must be flown in a relatively
nose-high attitude to maintain altitude, as compared to
flight with flaps extended. Losing altitude can be more
of a problem without the benefit of the drag normally
provided by flaps. A wider, longer traffic pattern may
be required in order to avoid the necessity of diving to
lose altitude and consequently building up excessive
airspeed.
On final approach, a nose-high attitude can make it
difficult to see the runway. This situation, if not anticipated,
can result in serious errors in judgment of
height and distance. Approaching the runway in a
relatively nose-high attitude can also cause the
perception that the airplane is close to a stall. This may
cause the pilot to lower the nose abruptly and risk
touching down on the nosewheel.
With the flaps retracted and the power reduced for
landing, the airplane is slightly less stable in the pitch
and roll axes. Without flaps, the airplane will tend to
float considerably during roundout. The pilot should
avoid the temptation to force the airplane onto the runway
at an excessively high speed. Neither should the
pilot flare excessively, because without flaps this
might cause the tail to strike the runway.
ASYMMETRIC (SPLIT) FLAP
An asymmetric “split” flap situation is one in which
one flap deploys or retracts while the other remains in
position. The problem is indicated by a pronounced
roll toward the wing with the least flap deflection
when wing flaps are extended/retracted.
The roll encountered in a split flap situation is countered
with opposite aileron. The yaw caused by the
additional drag created by the extended flap will
require substantial opposite rudder, resulting in a
cross-control condition. Almost full aileron may be
required to maintain a wings-level attitude, especially
at the reduced airspeed necessary for approach and
landing. The pilot therefore should not attempt to land
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with a crosswind from the side of the deployed flap,
because the additional roll control required to counteract
the crosswind may not be available.
The pilot must be aware of the difference in stall
speeds between one wing and the other in a split flap
situation. The wing with the retracted flap will stall
considerably earlier than the wing with the deployed
flap. This type of asymmetrical stall will result in an
uncontrollable roll in the direction of the stalled (clean)
wing. If altitude permits, a spin will result.
The approach to landing with a split flap condition
should be flown at a higher than normal airspeed. The
pilot should not risk an asymmetric stall and subsequent
loss of control by flaring excessively. Rather, the
airplane should be flown onto the runway so that the
touchdown occurs at an airspeed consistent with a safe
margin above flaps-up stall speed.
LOSS OF ELEVATOR CONTROL
In many airplanes, the elevator is controlled by two
cables: a “down” cable and an “up” cable. Normally,
a break or disconnect in only one of these cables will
not result in a total loss of elevator control. In most
airplanes, a failed cable results in a partial loss of
pitch control. In the failure of the “up” elevator cable
(the “down” elevator being intact and functional) the
control yoke will move aft easily but produce no
response. Forward yoke movement, however, beyond
the neutral position produces a nosedown attitude.
Conversely, a failure of the “down” elevator cable,
forward movement of the control yoke produces no
effect. The pilot will, however, have partial control of
pitch attitude with aft movement.
When experiencing a loss of up-elevator control, the
pilot can retain pitch control by:
• Applying considerable nose-up trim.
• Pushing the control yoke forward to attain and
maintain desired attitude.
• Increasing forward pressure to lower the nose and
relaxing forward pressure to raise the nose.
• Releasing forward pressure to flare for landing.
When experiencing a loss of down-elevator control,
the pilot can retain pitch control by:
• Applying considerable nosedown trim.
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AIRPLANE FLYING HANDBOOK 飞机飞行手册下(96)
