曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
For a complete description of the basic 757-200 speedbrake system, see the original Aircraft Maintenance Manual.
A. Speedbrake Autostow System - Description
The Speedbrake Autostow System contains the single direction cam/electric motor mechanism, which is located below the control stand. This mechanism interfaces with the speedbrake handle linkage. When the motor is activated, a deployed speedbrake handle will be pushed toward the stowed position. This action only occurs during high airspeed and heavy gross weight flight conditions. The function is controlled by the Speedbrake Autostow Controller (SAC).
B. Intended Function
The sole purpose of the Speedbrake Autostow System is to protect the wing structure from exceeding its analytic structural design load margins during a pitch-up maneuver in excess of 2.25 G, with the spoilers deployed when combined with certain combinations of airplane gross weight above 221,000 pounds for the 757-200 airplane and airspeed greater than 330 knots.
The Speedbrake Autostow System achieves this protection, when the speed brakes are deployed, by applying a force to the speedbrake handle. If a pilot is not counteracting this force, then the speedbrake handle will move to 50% of the flight detent position. The speedbrakes then move to the position commanded by the lever, which is approximately 14.7 degrees of outboard spoiler surface extension and 9.8, 7.5 degrees inboard spoiler surface extension (5&8, 6&7 respectively). The Speedbrake Autostow System does not alter the gain between the lever and the speedbrake surfaces.
C. Functional Description
The Speedbrake Autostow System commands the autostow actuator to retract when both the airspeed is greater than 330 knots and the gross weight is greater than 221,000 pounds for 757-200 airplane. The system deactivates, extends the autostow actuator when either airspeed drops below 325 knots or gross weight is less than 220,000 pounds for the 757-200. When the system is activated, an electric-motor-driven autostow actuator moves a cam mechanism, which has the following effects on the Speedbrake system:
Aviation Partners Boeing
757-200
MAINTENANCE MANUAL SUPPLEMENT
Part I
1) Position
The speedbrake lever retracts to a position 50% distance between the full up position and the down detent (as shown in Figure 1, 2). If the speedbrake lever is already at or less than this position, then the lever remains stationary.
2) Override Forces
The pilot may override the Autostow system's effect by applying the following extend forces to the speedbrake lever. Note: The forces below are incremental forces above the normal operating forces. Forces are also shown in Figure 3.
Between the Down stop and 50% of the full up position, the extend force is the same as when Autostow is deactivated (zero incremental force).
At the position 1/2 between the Down and the full up position, the override force increment is 20 pounds above normal until it reaches approximately 65. handle position. At the 65. handle position the increment force increases to 25 pounds for two degrees then reduces to zero increment up to the full up position.
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：757-200 MAINTENANCE MANUAL SUPPLEMENT Part I 维护手册补充(6)
