(f)
A single detector fault or alarm signal indication is given by the following: 1) The appropriate maintenance message is displayed on EICAS:
a) FWD CARGO DET 1 or 2. b) AFT CARGO DET 1 or 2.
B. Test____
(1)
When a test occurs, the AFOLTS card sends a signal to both detectors of each system. The signal turns on a testlamp in each detector. The test lamp shines directly onto the detector photocell, which triggers an alarm. The pilot lamp and the test lamp are wired in series, thus a successful test guarantees that the pilot lamp is operating properly.
(2)
If either detector in a system is found faulty, AFOLTS reconfigures that system to operate on the remaining detector. If the remaining detector sustains an alarm condition, then a fire warning indication results.
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(3)
Power-up mode:
(a) Whenever power is first applied to the battery bus, the engine, APU, and cargo compartment detection systems go through an automatic self-test. All single-detector maintenance messages are momentarily displayed on EICAs (P2). If any detector is found faulty, then the appropriate detector message remains on EICAS display, and the system is reconfigured to the other detector. If both detectors of a system are found faulty, then the FAIL P-RESET switchlight (on P8) comes on, and EICAS displays the advisory message - FIRE/OVHT SYS. A fire warning will not be initiated by a power-up test.
(4)
Manual system test:
(a)
When the ENG/APU/CARGO switch on the fire/overheat test panel (on P8) is pressed and held - the engine, APU, and cargo detection systems go through a self-test. All detector maintenance messages are displayed on EICAS, and after a two to four-second delay, a successful test terminates with all cargo fire indications.
(b)
The cargo fire indications are: 1) The red FWD and AFT CARGO FIRE switchlights (on P8) come
on.
2) The red FIRE light (on P1-3) comes on.
3) EICAS displays FWD and AFT CARGO FIRE warning messages (on
P2).
4) The red master warning lights (on P7) comes on.
5) The fire bell sounds on the flight deck aural warning
speakers.
(c) When the ENG/APU/CARGO switch is released, all messages and indications should clear - except for any faulty-detector messages which will remain on EICAS. The FAIL P-RESET switchlight, and EICAS advisory message - FIRE/OVHT SYS, will also remain on if there is a dual-detector failure.
(5) The manual system test and the power-up mode will not invalidate a fire alarm in progress.
C. Control
_______
(1) Turn-on procedure:
(a)
Provide electrical power (Ref 24-22-00).
(b)
Check that the following circuit breakers on overhead circuit breaker panel P11 are closed: 1) 11B26, FIRE DETECTION CARGO 1 or CARGO SMOKE DET 1 2) 11B27, FIRE DETECTION CARGO 2 or CARGO SMOKE DET 2 3) 11J24, FIRE DET ALTN PWR CARGO 4) 11S35, FIRE DET CARGO CONT or CARGO SMOKE BLOWER CONT 5) 11S36, FIRE DET FAN PWR or CAR SMK BLO
(c)
Check that the following Miscellaneous Electrical Equipment Panel P70 circuit breakers are closed. 1) 70B10, SMOKE DET BLOWER 1
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2) 3) 4) 70B11, SMOKE DET BLOWER 270B12, SMOKE DET BLOWER 370B13, SMOKE DET BLOWER 4
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