Mai n
M ia Gear
nGea r Struts
Strut s Exten
Comp d ed
res
ed
(0) (51) (102) (152) (203) (254) (305) (356) Clearance - inches (cm)
Pitch and Roll Limit Conditions
The Ground Contact Angles - Normal Landing figure illustrates body roll angle/pitch angles at which the airplane structure contacts the runway. Prolonged flare increases the body pitch attitude 2° to 3°. When prolonged flare is coupled with a misjudged height above the runway aft body contact is possible.
Fly the airplane onto the runway at the desired touchdown point and at the desired airspeed. Do not hold it off and risk the possibility of a tailstrike.
Note: A smooth touchdown is not the criterion for a safe landing.
Ground Contact Angles - Normal Landing
Conditions
.
Pitch about main gear centerline . Stabilizer full nose up
.
Slats fully extended . Elevator full down
.
Aileron full down . Struts compressed
.
Roll about outer tire centerline . Flaps 30
757-200
757-300
After Touchdown and Landing Roll
Avoid touching down with thrust above idle since this may establish an airplane
nose up pitch tendency and increases landing roll. After main gear touchdown, initiate the landing roll procedure. If the speedbrakes do not extend automatically move the speedbrake lever to the UP position without delay. Fly the nosewheel onto the runway smoothly by relaxing aft control column pressure. Control column movement forward of neutral should not be required. Do not attempt to hold the nosewheel off the runway. Holding the nose up after touchdown for aerodynamic braking is not an effective braking technique.
CAUTION: Pitch rates sufficient to cause airplane structural damage can
occur if large nose down control column movement is made
prior to nose wheel touchdown.
To avoid the risk of tailstrike, do not allow the pitch attitude to increase after touchdown. However, applying excessive nose down elevator during landing can result in substantial forward fuselage damage. Do not use full down elevator. Use an appropriate autobrake setting or manually apply wheel brakes smoothly with steadily increasing pedal pressure as required for runway condition and runway length available. Maintain deceleration rate with constant or increasing brake pressure as required until stopped or desired taxi speed is reached.
Speedbrakes
The speedbrake system is controlled with the SPEEDBRAKE lever (which is moved UP and DOWN). The speedbrake system consists of individual spoiler panels which the pilot can extend and retract by moving the SPEEDBRAKE lever.
The speedbrakes can be fully raised after touchdown while the nose wheel is lowered to the runway, with no adverse pitch effects. The speedbrakes spoil the lift from the wings, which places the airplane weight on the main landing gear, providing excellent brake effectiveness.
Unless speedbrakes are raised after touchdown, braking effectiveness may be reduced initially as much as 60%, since very little weight is on the wheels and brake application may cause rapid anti-skid modulation.
Normally, speedbrakes are armed to extend automatically. Both pilots should monitor speedbrake extension after touchdown. In the event auto extension fails, the speedbrake should be manually extended immediately.
Pilot awareness of the position of the speedbrake lever during the landing phase is important in the prevention of over-run. The position of the speedbrakes should be announced during the landing phase by the PNF. This improves the crew’s situational awareness of the position of the spoilers during landing and builds good habit patterns which can prevent failure to observe a malfunctioned or disarmed spoiler system.
Directional Control and Braking after Touchdown
If the nose wheel is not promptly lowered to the runway, braking and steering capability are significantly degraded and no drag benefit is gained. Rudder control is effective to approximately 60 knots. Rudder pedal steering is sufficient for maintaining directional control during the rollout. Do not use the nose wheel steering tiller until reaching taxi speed. In a crosswind, displace the control wheel into the wind to maintain wings level which aids directional control. Perform the landing roll procedure immediately after touchdown. Any delay markedly increases the stopping distance.
Stopping distance varies with wind conditions and any deviation from recommended approach speeds.
Factors Affecting Landing Distance
Advisory information for normal and non-normal configuration landing distances is contained in the PI section of the QRH. Actual stopping distances for a maximum effort stop are approximately 60% of the dry runway field length requirement. Factors that affect stopping distance include: height and speed over the threshold, glide slope angle, landing flare, lowering the nose to the runway, use of reverse thrust, speedbrakes, wheel brakes and surface conditions of the runway.
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本文链接地址:757 Flight Crew Training Manual 机组训练手册(70)