757 Flight Crew Training Manual 机组训练手册(75)

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On very slippery runways, landing the airplane using crab only reduces drift toward the downwind side at touchdown, permits rapid operation of spoilers and autobrakes because all main gears touchdown simultaneously, and may reduce pilot workload since the aircraft does not have to be de-crabbed before touchdown. However, proper rudder and upwind aileron must be applied after touchdown to ensure directional control is maintained.
Sideslip (Wing Low)
The sideslip crosswind technique aligns the aircraft with the extended runway centerline so that main gear touchdown occurs on the runway centerline.
The initial phase of the approach to landing is flown using the crab method to correct for drift. Prior to the flare the airplane centerline is aligned on or parallel to the runway centerline. Downwind rudder is used to align the longitudinal axis to the desired track as aileron is used to lower the wing into the wind to prevent drift. A steady sideslip is established with opposite rudder and low wing into the wind to hold the desired course.
Touchdown is accomplished with the upwind wheels touching just before the downwind wheels. Overcontrolling the roll axis must be avoided because overbanking could cause the engine nacelle or outboard wing flap to contact the runway. (See Ground Clearance Angles - Normal Landing charts, this chapter.)
Properly coordinated, this maneuver results in nearly fixed rudder and aileron control positions during the final phase of the approach, touchdown, and beginning of the landing roll. However, since turbulence is often associated with crosswinds, it is often difficult to maintain the cross control coordination through the final phase of the approach to touchdown.
If the crew elects to fly the sideslip to touchdown, it may be necessary to add a crab during strong crosswinds. (See the landing crosswind guidelines table, this chapter). Main gear touchdown is made with the upwind wing low and crab angle applied. As the upwind gear touches first, a slight increase in downwind rudder is applied to align the airplane with the runway centerline. At touchdown, increased application of upwind aileron should be applied to maintain wings level.

Rejected Landing
The rejected landing procedure is identical to the go-around procedure. Press GA and ensure go-around thrust is set or manually apply go-around thrust and select flaps 20 while rotating to go-around attitude. Retract the landing gear after a positive rate of climb is established. At a safe altitude, set command speed to flaps up maneuvering speed, or other speed as desired, and retract flaps on schedule. Auto speedbrakes retract and autobrakes disarm as thrust levers are advanced for a rejected landing initiated after touchdown.
WARNING: After reverse thrust is initiated, a full stop landing must be made.
Factors dictating this are:
. 
five seconds are required for a reverser to transition to the forward thrust
position

. 
a possibility exists that a reverser may not stow in the forward thrust
position.

 

 

Overweight Landing
Overweight landings may be safely accomplished by using normal landing procedures and techniques. There are no adverse handling characteristics associated with overweight landings. Landing distance is normally less than takeoff distance for flaps 25 or 30 landings at all gross weights. However, wet or slippery runway field length requirements should be verified from the landing distance charts in the Performance Inflight chapter of the Operations Manual. Brake energy limits will not be exceeded for flaps 25 or 30 landings at all gross weights.
Note: If flaps 30 approach speed (VREF 30 + additives for wind and gusts) is
within 10 knots of the Flap 30 placard speed, use flaps 25 and VREF 25 for
landing.
If stopping distance is a concern, reduce the landing weight as much as possible. At the captain’s discretion, reduce weight by holding at low altitude with a high drag configuration (gear down) to achieve maximum fuel burn-off.
Analysis has determined that, when landing at high gross weights at speeds associated with non-normal procedures requiring flaps set at 20 or less, maximum effort stops may exceed the brake energy limits. The gross weights where this condition can occur are well above maximum landing weights. For these non-normal landings, maximize use of the available runway for stopping.
Observe flap placard speeds during flap extension and on final approach. In the holding and approach patterns, maneuvers should be flown at the normal maneuver speeds. During flap extension, airspeed can be reduced by as much as 20 knots below normal maneuver speeds before extending to the next flap position. These lower speeds result in larger margins to the flap placards, while still providing normal bank angle maneuvering capability, but do not allow for a 15° overshoot margin in all cases.
　
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