LOWER CARGO FIRE EXTINGUISHING -FUNCTIONAL DESCRIPTION -FLOW
EFFECTIVITY BEJ ALL 26-23-00
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LOWER CARGO FIRE EXTINGUISHING -FUNCTIONAL DESCRIPTION -DUMP BOTTLES CIRCUIT
Bottle Discharge
Push the forward or aft cargo fire arm switch to arm the cargo fire extinguishing system. The switch makes a ground for the squib bottles 1A, 1B control relay. Push the cargo fire discharge switch to fire the squibs. That switch lets power from the hot battery bus go to energize the relay. With the relay energized, power from the hot battery bus goes to the bottle 1A and 1B squibs. At the same time, power goes through the discharge switch and the arm switch to the forward or aft flow valve squibs.
Discharge Indication
Pressure in the discharge line closes the forward or aft in-line pressure switch. The EEU makes a ground for the cargo fire discharge light and sends a signal to the AIMS. Advisory and maintenance messages show that the forward or aft in-line pressure switch is closed. The fire protection maintenance page also shows this condition.
When pressure inside a bottle decreases, the bottle pressure switch closes and makes a ground. The EEU sends a signal to the AIMS. Status and maintenance messages show low bottle pressure. The fire protection maintenance page also shows this condition.
Squib Test
The ELMS monitors the electrical continuity of the squib circuits. The ELMS does this check one time during each flight leg. The ELMS transmits data about an open squib circuit to the AIMS. Status and maintenance messages show that a squib circuit is faulty. The fire protection maintenance page also shows this condition.
You can also do a test of the squib circuits with the MAT.
Training Information Point
You can do a check of the bottle pressure switch circuits on the ground. Use a hex key to rotate the bottle pressure switch test
socket to close the switch. A bottle low pressure status
messages must show
The in-line pressure switch latches closed when the fire
extinguishing system operates. Use the reset button to set the switch contacts open.
EFFECTIVITY BEJ ALL 26-23-00
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D633W101-BEJ Sep 05/2002
LOWER CARGO FIRE EXTINGUISHING -FUNCTIONAL DESCRIPTION -DUMP BOTTLES CIRCUIT
EFFECTIVITY BEJ ALL 26-23-00
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D633W101-BEJ Jan 05/2002
LOWER CARGO FIRE EXTINGUISHING -FUNCTIONAL DESCRIPTION -METERED BOTTLES CIRCUIT
Bottle Discharge
When you push a cargo fire arm switch, a signal goes to the overhead panel ARINC 629 system (OPAS). The OPAS sends this data to the EEU. The discharge control circuit starts a twenty minute timer. After twenty minutes, the discharge control circuit makes a ground for the two squib control relays. The relays energize and send power from the hot battery bus to the three fire bottle squibs.
Discharge Indication
When pressure inside a bottle decreases, the bottle pressure switch closes and makes a ground. The ELMS electronics unit sends a signal to the AIMS. Status and maintenance messages show low bottle pressure. The fire protection maintenance page also shows this condition.
Squib Test
The ELMS monitors the electrical continuity of the squib circuits. The ELMS does this check one time during each flight leg. The ELMS transmits data about an open squib circuit to the AIMS. Status and maintenance messages show that a squib circuit is faulty. The fire protection maintenance page also shows this condition.
You can also do a test of the squib circuits with the MAT.
Training Information Point
You can do a check of the bottle pressure switch circuits on the ground. Use a hex key to rotate the bottle pressure switch test socket to close the switch. A bottle low pressure status messages must show.
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