曝光台 注意防骗
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excludes contaminated runway considerations.
* Landing distance varies with runway condition, wet or dry. Data
Increase in typical landing distance
due to improper landing techniques
1/2 brake pressure
High over threshold
Speedbrakes not extended
Speedbrakes not extended & thrust
reversers not used
TBD'
TBD' *
TBD' *
TBD’ *
TBD' *
•
•
•
•
•
•
•
•
(100' alt)
TBD'
October 31, 2006
777/787 Flight Crew Training Manual
Landing
Copyright © The Boeing Company. See title page for details.
FCT 777/787 Preliminary (TM) 6.35
Wheel Brakes
Braking force is proportional to the force of the tires on the runway and the
coefficient of friction between the tires and the runway. The contact area normally
changes little during the braking cycle. The perpendicular force comes from
airplane weight and any downward aerodynamic force such as speedbrakes.
The coefficient of friction depends on the tire condition and runway surface, (e.g.
concrete, asphalt, dry, wet or icy).
Automatic Brakes
Boeing recommends that whenever runway limited, using higher than normal
approach speeds, landing on slippery runways or landing in a crosswind, the
autobrake system be used.
For normal operation of the autobrake system select a deceleration setting.
Settings include:
• MAX AUTO: Used when minimum stopping distance is required.
Deceleration rate is less than that produced by full manual braking
• 3 or 4: Should be used for wet or slippery runways or when landing
rollout distance is limited
• 1 or 2: These settings provide a moderate deceleration suitable for all
routine operations.
Note: Autobrakes 2 or greater results in a continuous brake application, which
can increase carbon brake life.
Experience with various runway conditions and the related airplane handling
characteristics provide initial guidance for the level of deceleration to be selected.
Immediate initiation of reverse thrust at main gear touchdown and full reverse
thrust allow the autobrake system to reduce brake pressure to the minimum level.
Since the autobrake system senses deceleration and modulates brake pressure
accordingly, the proper application of reverse thrust results in reduced braking for
a large portion of the landing roll.
The importance of establishing the desired reverse thrust level as soon as possible
after touchdown cannot be overemphasized. This minimizes brake temperatures
and tire and brake wear and reduces stopping distance on very slippery runways.
The use of minimum reverse thrust as compared to maximum reverse thrust can
double the brake energy requirements and result in brake temperatures much
higher than normal.
After touchdown, crewmembers should be alert for autobrake disengagement
annunciations. The PM should notify the PF anytime the autobrakes disengage.
October 31, 2006
777/787 Flight Crew Training Manual
Landing
Copyright © The Boeing Company. See title page for details.
6.36 FCT 777/787 Preliminary (TM)
If stopping distance is not assured with autobrakes engaged, the PF should
immediately apply manual braking sufficient to assure deceleration to a safe taxi
speed within the remaining runway.
A table in the PI section of the QRH shows the relative stopping capabilities of the
available autobrake selections.
Transition to Manual Braking
The speed at which the transition from autobrakes to manual braking is made
depends on airplane deceleration rate, runway conditions and stopping
requirements. When transitioning to manual braking, keep the speedbrakes
deployed and use reverse thrust as required until taxi speed. This is especially
important when nearing the end of the runway where rubber deposits affect
stopping ability.
When transitioning from the autobrake system to manual braking, the PF should
notify the PM. Techniques for release of autobrakes can affect passenger comfort
and stopping distance. These techniques are:
• stow the speed brake handle. When stopping distance within the
remaining runway is assured, this method provides a smooth transition to
manual braking, is effective before or after thrust reversers are stowed,
and is less dependent on manual braking technique
• smoothly apply brake pedal force as in a normal stop, until the autobrake
system disarms. Following disarming of the autobrakes, smoothly release
brake pedal pressure. Disarming the autobrakes before coming out of
reverse thrust provides a smooth transition to manual braking
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787机组训练手册Flight Crew Training Manual 787(102)
