*
FIRE TEST IN PROGRESS warning message.
Release the fire/overheat test switch when the test is complete. The test is complete when the warning message FIRE TEST PASS or FIRE TEST FAIL shows. All the test indications go away when you release the switch.
Fire Test Pass
This message shows that the systems are serviceable. The systems may have faults which do not prevent flight. An example is a single loop fault in the engine fire detection system. Status messages show these faults. Look in the Dispatch Deviation Guide book to see if these faults limit flight operations.
Fire Test Fail
This message shows that one or more systems are not serviceable. These advisory messages show which system has a failure:
*
DET FIRE ENG L
*
DET FIRE ENG R
*
DET FIRE APU
*
DET FIRE CARGO FWD
*
DET FIRE CARGO AFT
*
DET FIRE WHEEL WELL.
Status messages show the failed LRUs.
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FIRE PROTECTION -TRAINING INFORMATION POINT -FIRE/OVERHEAT TEST
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FIRE PROTECTION -SQUIB TEST -FUNCTIONAL DESCRIPTION -INTRODUCTION
General
The EEU does an automatic test of all the fire extinguishing squibs. You can also use the MAT to do squib tests when the airplane is on the ground.
Squib Test Power
The hot battery bus supplies power through two circuit breakers for the fire extinguishing squib tests.
Squib Test Control
The squib test starts when the squib test control relay energizes. The EEU energizes the relay for these conditions:
*
At ELMS power-up
*
At engine shutdown with the airplane on the ground
*
When you do a squib test from the MAT.
The EEU test logic energizes the squib test control relay for 15 seconds and also makes a START SQUIB TEST signal.
Squib Test System BITE
A BITE circuit in the EEU monitors the squib test control relay through a signal conditioning card. If the relay does not operate properly, the EEU sends information to the AIMS. These status messages show that the squib test system has a failure: ENG/ APU SQUIB TEST or CARGO SQUIB TEST.
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FIRE PROTECTION -SQUIB TEST -FUNCTIONAL DESCRIPTION -TEST
General
The squib test does a check to make sure all the squibs have electrical continuity. The test also makes sure the circuit breakers that give power to the squibs are not open. Either condition causes a status message.
Squib Test Logic
When the START SQUIB TEST signal is active, the EEU monitors the squib test voltage. High or low voltage shows a defect in the squib circuit. If the squib test voltage is not in limits, the EEU latches a squib test failure signal and sends it to the AIMS. If you repair the squib circuit and do another test, the squib test failure signal resets.
The circuit breaker monitor does a check to make sure the circuit breaker that gives power to the squib is closed. If the circuit breaker is open, the EEU sends the squib test failure signal to the AIMS.
A status message shows when the AIMS receives a squib test failure signal from the EEU.
Squib Test Circuits
Each fire extinguishing squib has a similar test circuit.
Defects in the squib, circuit breaker, CB monitor, signal conditioning card, or their related wiring can cause a squib test to fail.
Training Information Point
A squib test failure causes a status message. After you correct the problem, do the related MAT ground test to clear the status message.
The same status message shows for a failed squib test and for low pressure in the related fire extinguishing bottle. Also, one message shows if the test fails for either squib (or the two squibs) in a cargo flow valve. Related maintenance messages help you find the problem.
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777 AIRCRAFT MAINTENANCE MANUAL
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BOEING PROPRIETARY -Copyright # -Unpublished Work -See title page for details.
ENGINE FIRE DETECTION -INTRODUCTION 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 防火 Fire Protection(3)
