W DOC AIRBUS | TSM A320F

Loss of Detection by Engine-2 Loop-A Pylon and Loop B Core

TASK 26-12-00-810-885-A
Loss of Detection by Engine-2 Loop-A Pylon and Loop B Core

1. Possible Causes
  • DET-FIRE, ENG 2 PYLON LOOP A [3WD2]
  • HARNESS-FIRE DET, ENG 2 PYLON LOOP A STUD A [31WD2]
  • HARNESS-FIRE DET, ENG 2 PYLON LOOP A STUD C [32WD2]
  • wiring
  • FDU-ENG2 [2WD2]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 26-12-00-810-860-A
Loss of Detection by Engine-2 Loop-B Core
AMM 26-12-00-200-802
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
AWM 261206
AMM 26-12-16-000-803
Removal of the Pylon Fire Detector
AMM 26-12-16-400-803
Installation of the Pylon Fire Detector
AMM 26-12-34-000-001
Removal of the Engine Fire-Detection Unit (FDU)
AMM 26-12-34-400-001
Installation of the Engine Fire-Detection Unit (FDU)
AMM 26-12-63-000-801
Removal of the Pylon Fire-Detector Harness
AMM 26-12-63-400-801
Installation of the Pylon-Fire Detector Harness
3. Fault Confirmation
Subtask 26-12-00-710-194-A ** ON A/C NOT FOR ALL
A. 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 26-12-00-810-137-A ** ON A/C NOT FOR ALL
A. If the test confirms the fault:
   (1) If the fire detector is damaged:
   (2) If there is no visual damage, do a visual inspection of the pylon fire-detector harnesses (31WD2) and (32WD2):
     (a) If one or more pylon fire-detector harness(es) is (are) damaged:
     (b) If there is no visual damage on the pylon fire-detector harnesses:
  • Disconnect the pylon fire-detector harnesses (31WD2) and (32WD2) from the engine-2-pylon loop-A fire-detector (3WD2).
  • On the responder, make sure that the resistance value is between 4275 ohms and 4725 ohms between pins A and C, ASM 261201.
       1 If the resistance values are out of the specified limits:
       2 If the resistance values are in the specified limits:
  • Do a continuity test of the wiring of the pylon fire-detector harnesses (31WD2) and (32WD2) AWM 261206.
         a If there is no continuity:
         b If there is continuity:
  • Do a check of the wiring between the first terminal-block and the pylon fire-detector harnesses (31WD2) and (32WD2), AWM 261206.

    * If the wiring is not correct:
    * - Repair it (them).
    * - Connect the pylon fire-detector harnesses (31WD2) and (32WD2) to the engine-2-pylon loop-A fire-detector (3WD2).

    * If the wiring is correct:
    * - Replace the FDU-ENG2 [2WD2] AMM 26-12-34-000-001 and AMM 26-12-34-400-001.
    * - Connect the pylon fire-detector harnesses (31WD2) and (32WD2) to the engine-2-pylon loop-A fire-detector (3WD2).
Subtask 26-12-00-810-168-A ** ON A/C NOT FOR ALL
B. For the fault message related to engine-2 loop-B Core, refer to the (Ref. TSM TASK 26-12-00-810-860).
[Rev.8 from Aug 2018] 2026.04.04 04:27:16 UTC
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