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DUCT LEAK AND OVERHEAT DETECTION -FAN CASE OVERHEAT DETECTORS
Purpose
The fan case overheat detector monitors the temperature in the area around the engine fan case. A leak in the engine anti-ice duct causes an overheat condition.
Physical Description
The fan case overheat detector has two elements: loop 1 and loop 2, attached to a metal support. Bolts connect the elements to the airplane wiring.
Each element has an outer conductor around an inner conductor. The separator between these conductors is an electrical insulator at temperatures less than the overheat set point (255F, 124C).
Functional Description
When the temperature is more than the set point, the separator conducts electricity. The electrical continuity between the inner and outer conductors gives an input to the DLODS control card.
Location
The fan case overheat detector attaches to the left side of the fan case inboard of the electronic engine control.
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DUCT LEAK AND OVERHEAT DETECTION -FAN CASE OVERHEAT DETECTORS
EFFECTIVITY BEJ ALL 26-18-00
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D633W101-BEJ Jan 05/2002
DUCT LEAK AND OVERHEAT DETECTION -STRUT OVERHEAT DETECTORS
Purpose
The strut overheat detectors monitor the temperature in the engine strut and the wing leading edge immediately inboard of the strut. A leak in the pneumatic duct causes an overheat condition.
Physical Description
Each side of the airplane has a dual loop strut overheat detector circuit. Each loop in the circuit has a set of elements that connect in series. Clips attach one long pair of elements to the front of the wing spar. A metal frame assembly contains another pair of elements. Electrical connectors and bolts connect the elements to the airplane wiring.
Each element has an outer conductor around an inner conductor. The separator between these conductors is an electrical insulator at temperatures less than the overheat set point (310F, 154C).
Functional Description
When the temperature is more than the set point, the separator conducts electricity. The electrical continuity between the inner and outer conductors gives an input to the DLODS control card.
Location
The strut overheat detectors are in two locations. One type is in the wing leading edge and another type is in the engine strut.
Access to the detector in the wing is through two panels on the bottom of the fixed leading edge. The panels are immediately inboard of the strut.
Access to the detector in the strut is through a panel in the right side of the strut.
Training Information Point
The strut overheat detection system has a fault locating feature for the detector loops. Maintenance messages include a zone number to help you find the location of a duct leak or a short circuit.
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DUCT LEAK AND OVERHEAT DETECTION -STRUT OVERHEAT DETECTORS
EFFECTIVITY BEJ ALL 26-18-00
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D633W101-BEJ Jan 05/2002
DUCT LEAK AND OVERHEAT DETECTION -WING DUCT LEAK DETECTORS
Purpose
Wing duct leak detectors monitor the pneumatic distribution ducts in the wing leading edges and in the environmental control system (ECS) bays for leaks.
Physical Description
Each side of the airplane has a dual loop wing duct leak detector circuit. Each loop in the circuit has five elements that connect in series. Clips along the length of the detectors attach the elements to the structure.
Each element has an outer conductor around an inner conductor. The separator between these conductors is an electrical insulator at temperatures less than the overheat set point (255F, 124C).
Functional Description
When the temperature is more than the set point, the separator conducts electricity. The electrical continuity between the inner and outer conductors gives an input to the DLODS control card.
Location
The wing duct leak detectors are near the pneumatic distribution system ducts in the wing leading edges and in the ECS bays.
Training Information Point
Where loop 1 uses a male connector, loop 2 uses a female connector to prevent cross connection of the loops.
The wing duct leak detection system has a fault locating feature for the detection loops. Maintenance messages include a zone number to help you find the location of a duct leak, short circuit, or open circuit.
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DUCT LEAK AND OVERHEAT DETECTION -WING DUCT LEAK DETECTORS 中國航空網 m.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：777 AMM 飛機維護手冊 防火 Fire Protection(20)
