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747-400 MAINTENANCE MANUAL
PARK BRAKE DISAGREE The parking brake valve and the handle position do not agree, and the brake control unit input changes to an open circuit. When the valve is out of position, the Antiskid and Brake Torque Limiting systems may not function correctly. The brake control unit will cause "ANTISKID OFF" and "BRAKE LIMITER" advisory messages to appear on EICAS.AUTOBRAKE CONTROL VALVE The autobrake control valve is tested during the system BITE test. This message would occur when the control valve pressure switch shows high pressure when the valve current is low (open not commanded), or when the control valve pressure switch shows low pressure when the valve current is high (open commanded).AUTOBRAKE THRUST LEVER SWITCH -(number 1 thru 4 specified) FAIL Thrust lever switch showed not advanced (ground for levers 1 & 3, 28 vdc for levers 2 & 4) when air/ground signal goes from ground to air mode. Thrust lever switch shows advanced (open circuit) when air/ground signal goes from air to ground mode.AUTOBRAKE SOLENOID VALVE FAIL The solenoid pressure switch shows high pressure when the solenoid valve current is low (open not commanded). The pressure switch shows low pressure when solenoid valve current is high (open commanded).AUTOBRAKE SELECTOR SWITCH FAIL The selector switch will not move from a deceleration selection position to disarm when the autobrake system signals a disarm. This message can be caused manually by holding the selector switch in a deceleration selection position when a disarm condition exists. This message will also occur if the autobrake card has more than one deceleration selection energized at the same time.BSCU FAIL This is usually a BITE or microprocessor malfunction.AUTOBRAKE CONTROL VALVE PRESSURE SWITCH FAIL The autobrake control valve pressure switch is tested during the system BITE test. This message would occur when the control valve pressure switch shows high pressure when the valve current is low (open not commanded) or when the control valve pressure shows low pressure when the valve current is high (open commanded).AUTOBRAKE SOLENOID VALVE PRESSURE SWITCH FAIL The solenoid pressure switch shows high pressure when the solenoid valve current is low or the pressure switch shows low pressure when the solenoid valve current is high. The system BITE test will isolate the switch failure. If the switch shows high pressure while the autobrake is not powered, and EICAS AUTOBRAKES advisory message will result.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
32-42-00
ALL ú ú 01 Page 57 ú Oct 10/92
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
(r)
BRAKE DISABLE SWITCH -(number 1 thru 16 specified) FAIL This shows that one or two of the antiskid BRAKE INDICATION DISABLE switches is in other than the NORM position. If the switch position does not agree with the message there is a circuit malfunction in the BSCU.
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GEAR HANDLE INPUTS DISAGREE This message occurs when the primary and alternate-gear-handle-position-discrete signals do not agree.
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CMC>BSCU BUS FAIL The CMC is not able to transmit, or the data format is not correct for the brake system control unit.
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BSCU>CMC BUS FAIL The brake system control unit is not able to transmit to the CMC.
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BSCU NO TEST RESPONSE The brake system control unit does not respond to a test request. Make sure that the brake system control unit has electric power.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
32-42-00
ALL ú ú 01 Page 58 ú Oct 10/92
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
FAULT ISOLATION/MAINT MANUAL
BRAKE CONTROL SYSTEM
COMPONENT 102 SHT FIG. QTY ACCESS/AREA AMM REFERENCE
ASSEMBLY - ELECTRONIC COMPONENT 2 1 125B, CTR EQUIP CENTER, E9, 32-42-01
BRAKE SYS CONT UNIT, M80
ASSEMBLY - L AUTOBRAKE SHUTTLE VALVE 8 1 AFT BULKHD, L WING GEAR WHL WELL 32-42-12
ASSEMBLY - L BODY GEAR ANTISKID MODULE 4 1 L BODY GEAR WHL WELL, AFT 32-42-02
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本文鏈接地址：747-400 AMM 飛機(jī)維護(hù)手冊 起落架 LANDING GEAR 7(3)
