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but in no case less than critical engine-out minimum
control speed (VMC). Some multiengine pilots prefer
to delay full flap extension to short final with the landing
assured. This is an acceptable technique with appropriate
experience and familiarity with the airplane.
In the roundout for landing, residual power is gradually
reduced to idle. With the higher wing loading of
multiengine airplanes and with the drag from two
windmilling propellers, there will be minimal float.
Full stall landings are generally undesirable in twins. The
airplane should be held off as with a high performance
single-engine model, allowing touchdown of the main
wheels prior to a full stall.
Under favorable wind and runway conditions, the
nosewheel can be held off for best aerodynamic braking.
Even as the nosewheel is gently lowered to the
runway centerline, continued elevator back pressure
will greatly assist the wheel brakes in stopping the
airplane.
If runway length is critical, or with a strong crosswind,
or if the surface is contaminated with water, ice or
snow, it is undesirable to rely solely on aerodynamic
braking after touchdown. The full weight of the airplane
should be placed on the wheels as soon as
practicable. The wheel brakes will be more effective
than aerodynamic braking alone in decelerating the
airplane.
Once on the ground, elevator back pressure should be
used to place additional weight on the main wheels and
to add additional drag. When necessary, wing flap
retraction will also add additional weight to the wheels
and improve braking effectivity. Flap retraction during
the landing rollout is discouraged, however, unless
there is a clear, operational need. It should not be
accomplished as routine with each landing.
Some multiengine airplanes, particularly those of the
cabin class variety, can be flown through the roundout
and touchdown with a small amount of power. This is
an acceptable technique to prevent high sink rates and
to cushion the touchdown. The pilot should keep in
mind, however, that the primary purpose in landing is
to get the airplane down and stopped. This technique
should only be attempted when there is a generous
Approaching Traffic Pattern
1. Descent Checklist
2. Reduce to Traffic Pattern Airspeed and Altitude
Downwind
1. Flaps - Approach Position
2. Gear Down
3. Before Landing Checklist
Base Leg
1. Gear-Check Down
2. Check for Conflicting
Traffic
Final
1. Gear-Check Down
2. Flaps-Landing Position
Airspeed- 1.3 Vs0 or
Manufacturers Recommended
Figure 12-8. Normal two-engine approach and landing.
12-15
Ch 12.qxd 5/7/04 9:54 AM Page 12-15
12-16
margin of runway length. As propeller blast flows
directly over the wings, lift as well as thrust is produced.
The pilot should taxi clear of the runway as soon as
speed and safety permit, and then accomplish the “after
landing” checklist. Ordinarily, no attempt should be
made to retract the wing flaps or perform other checklist
duties until the airplane has been brought to a halt
when clear of the active runway. Exceptions to this
would be the rare operational needs discussed above,
to relieve the weight from the wings and place it on the
wheels. In these cases, AFM/POH guidance should be
followed. The pilot should not indiscriminately reach
out for any switch or control on landing rollout. An
inadvertent landing gear retraction while meaning to
retract the wing flaps may result.
CROSSWIND APPROACH
AND LANDING
The multiengine airplane is often easier to land in a
crosswind than a single-engine airplane due to its
higher approach and landing speed. In any event, the
principles are no different between singles and twins.
Prior to touchdown, the longitudinal axis must be
aligned with the runway centerline to avoid landing
gear side loads.
The two primary methods, crab and wing-low, are
typically used in conjunction with each other. As
soon as the airplane rolls out onto final approach, the
crab angle to track the extended runway centerline is
established. This is coordinated flight with adjustments
to heading to compensate for wind drift either
left or right. Prior to touchdown, the transition to a
sideslip is made with the upwind wing lowered and
opposite rudder applied to prevent a turn. The airplane
touches down on the landing gear of the upwind wing
first, followed by that of the downwind wing, and
then the nose gear. Follow-through with the flight
controls involves an increasing application of aileron
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AIRPLANE FLYING HANDBOOK 飞机飞行手册下(36)
