曝光台 注意防骗
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and the brakes can be applied. The nose should be lowered
for any aerodynamic braking at the higher speeds.
Lowering the nose also provides greater force on the front
wheel for superior braking effectiveness. Any skidding of the
front wheel with braking causes the loss of directional control
of the WSC aircraft and the skidding must be stopped by
letting up on the brake. Skidding can be the greatest problem
operating on slick surfaces such as wet grass. Rear wheel
braking systems are heavier and more complex, but provide
better braking force because there are two wheels instead of
one and there is more weight on the rear wheels. Braking
effectiveness should be evaluated by the pilot for each type
of runway being used. If the available runway permits, the
speed of the aircraft should be allowed to dissipate in a normal
manner with minimum use of brakes. [Figure 11-15]
The control bar serves the same purpose on the ground as
in the air—it changes the lift and drag components of the
wings. During the after-landing roll, the control bar should
be used to keep the wings level in much the same way it is
used in fl ight. If a wing starts to rise, roll control should be
applied to lower it. Procedures for crosswind conditions are
explained further in the Crosswind Approach and Landing
section of this chapter.
Effect of Headwinds During Final
Approach
A headwind plays a prominent role in the gliding distance
over the ground. Strong headwinds decrease the glide as
shown in the comparison in Figure 11-16A with no wind
normal glide versus Figure 11-16B in headwind with steeper
glide. To account for a steeper glide in a headwind, the base
leg must be positioned closer to the approach end of the
runway than would be required with a light wind. Therefore,
11-9
34
Glidepath with Wind
Idle Power
High Wind
B Effect of Wind on Glidepath Intended Landing
34
Normal Glidepath No Headwind
Idle Power
A Glidepath in Calm Winds Intended Landing
34
Decreased Glidepath
in High Wind
Idle Power
Power Application Maintains Glidepath to Runway in High Winds
Intended Landing
High Wind
D Effect on Glidepath with Power Application in High Winds
Too far away base leg setup in high winds
34
Glidepath with wind
Idle Power
Set up a base closer to runway
In high winds because glidepath is steeper
Intended Landing
High Wind
C High Wind Base Leg Setup
Proper base Leg setup in high winds
Figure 11-16. Headwinds for final approach.
the base leg must be made closer to the runway to land in
the intended area in a headwind. [Figure 11-16 C] However,
if more headwind is experienced during fi nal approach,
increased power is required to make the intended landing
area. [Figure 11-16 D]
Naturally, the pilot does not have control over the wind but
may correct for its effect on the aircraft’s descent by adjusting
the base leg of the pattern. The wind can vary signifi cantly
at different attitudes and locations in the pattern. If the pilot
does not notice the headwind until the base leg, the base
11-10
Figure 11-17. Modified base leg if winds higher than intended are encountered during the base leg of the pattern.
34
NORMAL CALM WIND APPROACH
If crosswind encountered
on base leg—
modify base leg
If tailwind encountered
on downwind leg—
modify base leg
Intended Touchdown Point
leg should be cut short and the pilot should head towards
the runway sooner. This would provide the best possibility
of making the runway if there is an engine failure in this
situation. [Figure 11-17]
Additionally, during strong headwinds, more energy (power
and airspeed) should be used since the wind gradient (slowing
of the wind near the ground because of the friction of the
ground) could reduce the airspeed and cause a stall on
approach near the ground in higher winds.
Stabilized Approach Concept
A stabilized approach is one in which the pilot establishes and
maintains a constant angle glidepath toward a predetermined
point on the landing runway. It is based on the pilot’s judgment
of certain visual clues and depends on the maintenance of a
constant fi nal descent airspeed.
An aircraft descending on fi nal approach at a constant rate
and airspeed is traveling in a straight line toward a point on
the ground ahead. This point is not the point on which the
aircraft touches down because some fl oat inevitably occurs
during the roundout.
The point toward which the aircraft is progressing is termed
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Weight-Shift Control Aircraft Flying Handbook(118)
