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SPOILER AND SPEEDBRAKE CONTROL -SPOILER SURFACES
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SPOILER AND SPEEDBRAKE CONTROL -FUNCTIONAL DESCRIPTION
General
The roll and speedbrake control system for the inboard and outboard spoilers uses input command signals from the:
*
Wheel position transducers
*
Force transducer
*
Speedbrake lever transducer assembly.
The ACEs receive the input signals and transmit them to the PFCs. The ACEs supply output command signals to the spoiler PCUs.
The roll control system for the cable-controlled spoilers uses input commands from the cable system. The speedbrake control system for these spoilers uses electrical command signals from the ACEs.
Wheel Position Transducers
The C ACE and R ACE each receive signals from two wheel position transducers. The L1 ACE and L2 ACE each receive signals from one wheel position transducer. After they change the signals to digital format, the ACEs send these signals to the PFCs through the flight controls ARINC 629 buses.
Each PFC receives input signals from all six wheel position transducers. Each PFC selects which signal to use by mid-value selection and averaging.
Force Transducer
The two LVDTs of the force transducer send signals to the L2 ACE and the C ACE. The ACEs transmit these signals to the PFCs.
Speedbrake Lever Transducer
The four speedbrake lever transducer RVDTs send signals to the four ACEs. The ACEs transmit these signals to the PFCs.
Electrically-Controlled PCUs
Each ACE sends command signals to the EHSV of the assigned spoiler PCUs. The PCU sends feedback signals to its assigned ACE from the actuator piston position LVDT.
Cable-Controlled PCUs
The L2 ACE sends speedbrake control command signals to the PCUs of spoilers 4 and 11. The speedbrake command signal goes to the speedbrake solenoid valve. The PCU sends feedback signals to its assigned ACE from the actuator piston position LVDT.
The cable system supplies mechanical roll command input to the main control valve of spoiler 4 and 11 PCUs.
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SPOILER AND SPEEDBRAKE CONTROL -FUNCTIONAL DESCRIPTION
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SPOILER AND SPEEDBRAKE CONTROL -FUNCTIONAL DESCRIPTION -ACE SERVO LOOP
General
The ACE contains a control servo loop circuit for all the electrically-controlled PCUs. This control servo loop circuit is also for the cable-controlled PCUs in speedbrake operation.
In normal and secondary modes of operation of the PFCS, the PFC sends mixed roll and speedbrake command signals to the ACE for the electrically-controlled PCUs. In direct mode, the ACE calculates the mixed command signals to these PCUs.
In normal mode of operation of the PFCS, the PFC sends speedbrake command signals to the cable-controlled PCUs (spoiler 4 and 11). In secondary and direct modes, there is no speedbrake command signal from the PFCs and ACEs to these PCUs.
Servo Loop Operation
The ACEs send the command signals to the EHSV of the electrically-controlled PCUs. In normal mode, they also go to the speedbrake solenoid valves of the cable-controlled PCUs. The ACEs monitor the PCU command signals for failures.
The actuator position LVDT measures the movement of the actuator and supplies a feedback signal to the ACEs to close the servo loop, and to monitor faults. This signal also goes to the PFC.
Failure Monitor
The ACE has a failure monitor to do a check of the correct operation of the PCU. The monitor uses the ACE command signal and the feedback signal from the actuator position LVDT.
If the ACE finds a failed spoiler PCU, it connects to ground the EHSV of both PCUs of the spoiler pair. The EHSV of each PCU has a mechanical and magnetic bias to command the actuator to retract when there is no electrical command to the EHSV.
Indications
The EICAS advisory message SPOILERS shows when one or more pair of spoilers does not operate. This condition causes the message to show in normal, secondary, and direct modes.
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SPOILER AND SPEEDBRAKE CONTROL -FUNCTIONAL DESCRIPTION -ACE SERVO LOOP
EFFECTIVITY BEJ ALL 27-61-00 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：777 AMM 飞机维护手册 飞行操纵 Flight Controls 2(53)
