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should be accomplished in accordance with an
approach and landing profile developed for the particular
airplane. [Figure 15-23]
SIGNIFICANT DIFFERENCES
Asafe approach in any type of airplane culminates in a
particular position, speed, and height over the runway
threshold. That final flight condition is the target
window at which the entire approach aims. Propeller
powered airplanes are able to approach that target from
wider angles, greater speed differentials, and a larger
variety of glidepath angles. Jet airplanes are not as
responsive to power and course corrections, so the
final approach must be more stable, more deliberate,
more constant, in order to reach the window accurately.
The transitioning pilot must understand that, in spite
of their impressive performance capabilities, there are
six ways in which a jet airplane is worse than a piston
engine airplane in making an approach and in
correcting errors on the approach.
• The absence of the propeller slipstream in
producing immediate extra lift at constant
airspeed. There is no such thing as salvaging a
misjudged glidepath with a sudden burst of
immediately available power. Added lift can
only be achieved by accelerating the airframe.
Not only must the pilot wait for added power but
even when the engines do respond, added lift
will only be available when the airframe has
responded with speed.
• The absence of the propeller slipstream in
significantly lowering the power-on stall speed.
There is virtually no difference between poweron
and power-off stall speed. It is not possible in
a jet airplane to jam the thrust levers forward to
avoid a stall.
• Poor acceleration response in a jet engine from
low r.p.m. This characteristic requires that the
approach be flown in a high drag/high power
1. Reset Bug to VREF
2. Review Airport Characteristics
3. Complete Descent and Begin
Before Landing Checklist
Abeam Runway Midpoint
• Flaps T/O Approach
• VREF + 20 Minimum
1500' Above
Field Elevation
• Complete Before
Landing Checklist
• Maximum Bank 30°
• Clear Final Approach
Rollout
• Reduce Speed to VREF
• Altitude Callouts
• Stabilized in Slot
DO NOT MAKE FLAT
APPROACH
Touchdown
• Extend Speed
Brake
• Apply Brakes
• Thrust reverser or
Drag Chute as
Required
Fly VREF
Abeam Touchdown Point
• Gear Down
Turning Base
• Flaps Land
• Initially Set Fuel Flow to 400 Lb./Engine
• Start Descent
• VREF + 10 Minimum on Base
APPROACH PREPARATIONS
Figure 15-23.Typical approach and landing profile.
Ch 15.qxd 5/7/04 10:22 AM Page 15-20
15-21
configuration so that sufficient power will be
available quickly if needed.
• The increased momentum of the jet airplane
making sudden changes in the flightpath
impossible. Jet airplanes are consistently heavier
than comparable sized propeller airplanes. The
jet airplane, therefore, will require more indicated
airspeed during the final approach due to a
wing design that is optimized for higher speeds.
These two factors combine to produce higher
momentum for the jet airplane. Since force is
required to overcome momentum for speed
changes or course corrections, the jet will be far
less responsive than the propeller airplane and
require careful planning and stable conditions
throughout the approach.
• The lack of good speed stability being an
inducement to a low speed condition. The drag
curve for many jet airplanes is much flatter than
for propeller airplanes, so speed changes do not
produce nearly as much drag change. Further, jet
thrust remains nearly constant with small speed
changes. The result is far less speed stability.
When the speed does increase or decrease, there
is little tendency for the jet airplane to re-acquire
the original speed. The pilot, therefore, must
remain alert to the necessity of making speed
adjustments, and then make them aggressively in
order to remain on speed.
• Drag increasing faster than lift producing a high
sink rate at low speeds. Jet airplane wings
typically have a large increase in drag in the
approach configuration. When a sink rate does
develop, the only immediate remedy is to
increase pitch attitude (angle of attack). Because
drag increases faster than lift, that pitch change
will rapidly contribute to an even greater sink
rate unless a significant amount of power is
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AIRPLANE FLYING HANDBOOK 飞机飞行手册下(85)
