W DOC AIRBUS | TSM A320F

Loss of Two ENG 1 Detection Loops

TASK 26-12-00-810-842-A
Loss of Two ENG 1 Detection Loops

1. Possible Causes
  • DET-FIRE, ENG 1 PYLON LOOP A [3WD1]
  • DET-FIRE, FAN LOOP A [4000WD1]
  • DET-FIRE, CORE LOOP A [4001WD1]
  • wiring of Loop A I/P from the engine 1 FDU to the three loop A fire detectors
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 24-41-00-861-002
Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002
De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 26-12-00-200-001
Visual Inspection of the Engine Fire Detection System
AMM 26-12-00-710-002
Operational Test of the Engine Fire and Overheat Detection with the Centralized Fault Display System (CFDS)
ASM 261201
AMM 26-12-15-000-041
Removal of the Fan Fire Detectors
AMM 26-12-15-400-041
Installation of the Fan Fire Detectors
AMM 26-12-16-000-001
Removal of the Pylon Fire Detectors
AMM 26-12-16-400-001
Installation of the Pylon Fire Detectors with the Tool (98D26203003000)
AMM 26-12-17-000-040
Removal of the Core Fire Detectors
AMM 26-12-17-400-040
Installation of the Core Fire Detectors
AMM 31-60-00-860-001
EIS Start Procedure
3. Fault Confirmation
Subtask 26-12-00-860-056-A ** ON A/C NOT FOR ALL
A. Job Set-Up
   (1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
   (2) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
Subtask 26-12-00-710-134-A ** ON A/C NOT FOR ALL
B. Test
   (1) Do the operational test of the engine fire and overheat detection from the Multipurpose Control and Display Unit (MCDU) AMM 26-12-00-710-002.
4. Fault Isolation
Subtask 26-12-00-810-095-D ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message ENG1 FIRE LOOP A + LOOP B:
   (1) If one or more fire detector(s) is (are) damaged:
   (2) If there is no visual damage and if the fault continues:
  • disconnect the connector 2WD1-A from the engine 1 FDU (2WD1)
  • on the connector, on the wiring side, make sure that the equivalent resistance value between pins J and K is between 1425 ohms and 1575 ohms.
     (a) If the equivalent resistance value is not correct and is:
. between 2137 ohms and 2363 ohms: there is one defective fire detector
. between 4275 ohms and 4725 ohms: there are two defective fire detectors
. infinite: there are three defective fire detectors or a defective wiring.
  • disconnect the electrical harness from the three loop A fire detectors
  • on the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms:
    . between pins A/A and A/D for the engine 1 pylon loop A fire detector (3WD1) and the fan loop A fire detector (4000WD1),
    . between pins A/A and A/C for the core loop A fire detector (4001WD1).
       1 If the resistance value is not correct:
       2 If the resistance value is correct:
  • do a check and repair the wiring of Loop A I/P from the engine 1 FDU to the three loop A fire detectors ASM 261201.
Subtask 26-12-00-710-135-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.
5. Close-up
Subtask 26-12-00-860-057-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
   (1) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
   (2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.
[Rev.8 from Aug 2018] 2026.04.04 04:27:11 UTC
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