(5)
If necessary, adjust support channel until above tolerances are met then tighten installation bolts.
(6)
Repeat steps (1) thru (4) until each switch is closed for DN and OFF position of landing gear lever and open for UP position with tolerances specified.
(7)
Close all circuit breakers opened in 1.B.(1).
511
May 20/82 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 32-42-51 Page 501
Landing Gear Lever Up Switches Adjustment 500
32-42-51 Figure 501 Aug 15/67
Page 502
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
AUTOMATIC BRAKING SYSTEM - DESCRIPTION AND OPERATION
EFFECTIVITY
AS N730AS, N740AS, and N742AS
1. General
A. The automatic braking system operates in conjunction with the antiskid system to obtain automatic (feet off) braking. A single modulating valve supplies control pressure to all four brakes. Controls for the system are contained in the autobrake control panel located on the pilot's forward instrument panel P2-2. Three deceleration rates (MIN, MED, MAX) during landing are available. The automatic braking system bypasses the pilot's brake metering valves and applies system pressure directly to the brake units through the antiskid valves. The antiskid module (M162), responding to selected deceleration signals from the automatic braking system, operates an autobrake pressure control module which modulate brake pressure as required to meet the selected aircraft deceleration rate. Automatic brake pressure is applied in pairs with the inboard and outboard brakes forming the pairs. The deceleration rate circuits are contained in the antiskid control module, but are energized when the automatic braking system is turned on. The automatic braking system performs a self-check each time the system is turned on by the AUTOBRAKE selector switch and illuminates an AUTOBRAKE DISARM light on the P2-2 panel. The light will also illuminate for both failure detection and crew-initiated disarming.
B. The antiskid system has priority over the automatic braking system at all times for skid and locked wheel protection. The pilot can override the automatic braking system at any time by applying brake pressure equal to or higher than that by the automatic braking system. Go-around protection is obtained through engine throttle actuated switches. Advancement of the throttles causes immediate dropout of the automatic braking system.
C. The automatic braking system consists of an autobrake control panel, an autobrake pressure control module, three hydraulic pressure switches, four shuttle valves, a hydraulic fuse, and autobrake digital circuits located on a selected deceleration card in the M162 antiskid module. Additional control inputs are furnished by wheel speed relays, air-ground sensing relay, speed brake arming switch and engine throttle switches. Antiskid system components are incorporated into the autobrake system as a necessary part of the system. 28-volt dc power for autobrake operation is supplied to the antiskid modules through the AUTOBRAKE CONTR circuit breaker on the P6-3 panel. An operational antiskid system is pre-requisite of the automatic braking system.
Jan 20/82 32-43-01 Page 1
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
2. Autobrake Control Panel (Detail A, Fig. 1)
A. The autobrake control panel, located directly below the antiskid ON-OFF switches on the pilot's forward instrument panel P2-2, consists of an AUTOBRAKE selector switch, an amber AUTOBRAKE DISARM light, two relays, R289 and R290 (Fig. 3). The relays are located behind the control panel.
(1)
The AUTOBRAKE selector switch (S583) is a rotary, four-position switch. The functions of the switch are to arm the system by providing 28-volt dc autobrake power to the antiskid control module, select a MIN, MED, or MAX airplane deceleration level, and illuminate the AUTOBRAKE DISARM light.
(2)
The AUTOBRAKE DISARM indicator light illuminates when the AUTOBRAKE selector switch is in any position other than off and a crewmember disarms the system through the manual application of the brakes, or if there is any malfunction resulting in an autobrake system disarm. Immediately upon moving the selector switch to MIN, MED or MAX a turn-on self check (TOSC) is initiated by the system. It will last approximately 2.5 seconds, and if any malfunction is detected during the check the AUTOBRAKE DISARM light will illuminate. If the airplane is in the ground mode the AUTOBRAKE DISARM light will illuminate on completion of the check. The light can be extinguished by placing the AUTOBRAKE selector switch to OFF.
(3)
The (A/B DISARM) relay R290 provides switching functions for disarming the system when the arming requirements for landing operations are not fully met. The relay will reset when the AUTOBRAKE selector switch is placed to OFF.
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