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the aircraft is required.
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34
17
Normal or Steep-
Angle Approach
Alternating Turns
to Lose Altitude
Minimum
400 feet AGL
Top View
Alternating Turns
on Runway Centerline
Runway
Centerline
Figure 11-30. Alternating turns used if too high to lose enough altitude to position for a normal or steep-angle approach.
With experience and practice, altitudes up to approximately
1,000 feet can be estimated with fair accuracy, while above
this level the accuracy in judgment of height above the
ground decreases since features tend to merge. The best aid
in perfecting the ability to judge height above this altitude is
altimeter indications and associating them with the general
appearance of the Earth.
The judgment of altitude in feet, hundreds of feet, or thousands
of feet is not as important as the ability to estimate gliding
angle and its resultant distance. The pilot who knows the
normal glide angle of the aircraft can estimate with reasonable
accuracy the approximate spot along a given ground path
at which the aircraft lands, regardless of altitude. The pilot
who also has the ability to estimate altitude accurately can
judge how much maneuvering is possible during the glide,
which is important to the choice of landing areas in an actual
emergency.
Unlike a normal approach in which power is available when
needed, for a power-off approach the power is fi xed at the
idle setting. Pitch attitude is adjusted to control the airspeed,
which also changes the glide or descent angle. As discussed
in the basic fl ight maneuvers descents and the steep approach
maneuver, lowering the nose to a speed above the best glide
angle causes the descent angle to steepen. If the airspeed is
too high, raise the nose, and when the airspeed is too low,
lower the nose. If the pitch attitude is raised too high, the
aircraft settles rapidly due to low airspeed and insuffi cient
lift. For this reason, never try to stretch a glide to reach the
desired landing spot.
Uniform approach patterns such as the 90°, 180°, or 360°
power-off approaches are described further in this chapter.
Practice in these approaches provides the pilot with a basis
on which to develop judgment in gliding distance and in
planning an approach. The 180° power-off approach from
pattern altitude should be the normal landing procedure in
calm winds. This should become routine and develop the
ability to accurately judge the landing for an engine-out
situation. Remember, the steep approach technique can
always be used if the aircraft is a little high, but do not stretch
a glide by lowering the speed if too low.
The basic procedure in these approaches involves closing
the throttle at a given altitude and gliding to a key position.
This position, like the pattern itself, must not be allowed to
become the primary objective; it is merely a convenient point
in the air from which the pilot can judge whether the glide
safely terminates at the desired spot. The selected key position
should be one that is appropriate for the available altitude
and the wind condition. From the key position, the pilot must
constantly evaluate the situation. It must be emphasized that,
although accurate spot touchdowns are important, safe and
properly executed approaches and landings are vital. The
pilot must never sacrifi ce a good approach or landing just to
land on the desired spot.
All power-off approaches must be practiced to avoid
interfering with normal traffi c fl ow at busy airports, so the
place and timing must be evaluated by the instructor to
prevent airport traffi c confl icts. This is especially important
for the 360° power-off approach.
90° Power-Off Approach
The 90° power-off approach is made from a base leg and
requires only a 90° turn onto the fi nal approach. The approach
path may be varied by positioning the base leg closer to or
farther away from the approach end of the runway according
to wind conditions. [Figure 11-31] The glide from the key
11-23
36
1
2
3
1. Strong Wind
Set up closest base for
steeper glideslope on final
2. Medium Wind
Set up closer base for
steeper glideslope on final
3. Light Wind
Set up normal base for
normal final
Figure 11-31. Plan the base leg according to wind conditions.
position on the base leg through the 90° turn to the fi nal
approach is the fi nal part of all accuracy landing maneuvers.
Steep approach procedures may be used during the fi nal
approach if needed.
　
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本文鏈接地址：Weight-Shift Control Aircraft Flying Handbook(127)