W DOC AIRBUS | TSM A320F

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

TASK 26-12-00-810-808-A
Loss of Detection by Engine-2 Loop A and Loop B

1. Possible Causes
  • DET-FIRE, ENG 2 PYLON LOOP A [3WD2]
  • DET-FIRE, CORE VENT LOOP A [4001WD1]
  • DET-FIRE, CORE AGB LOOP A [4002WD1]
  • HARNESS-FIRE DET, ENG 2 PYLON LOOP A STUD A [31WD2]
  • HARNESS-FIRE DET, ENG 2 PYLON LOOP A STUD C [32WD2]
  • DET-FIRE, ENG 2 PYLON LOOP B [4WD2]
  • DET-FIRE, FAN LOOP A [4000WD1]
  • DET-FIRE, FAN LOOP B [4000WD2]
  • DET-FIRE, CORE LOOP B [4001WD2]
  • wiring
  • FDU-ENG2 [2WD2]
  • terminal-block
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 26-12-00-810-806-A
Loss of Detection by Engine-2 Loop B
AMM 26-12-00-200-001
Visual Inspection of the Engine Fire Detection System
AMM 26-12-00-200-003
Visual Inspection of the Engine Fire Detection System
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 26-12-15-000-041
Removal of the Fan Fire Detectors
AMM 26-12-15-000-042
Removal of the Fan Fire Detectors
AMM 26-12-15-400-041
Installation of the Fan Fire Detectors
AMM 26-12-15-400-042
Installation of the Fan Fire Detectors
AMM 26-12-16-000-001
Removal of the Pylon Fire Detectors
AMM 26-12-16-000-803
Removal of the Pylon Fire Detector
AMM 26-12-16-400-001
Installation of the Pylon Fire Detectors with the Tool (98D26203003000)
AMM 26-12-16-400-803
Installation of the Pylon Fire Detector
AMM 26-12-17-000-040
Removal of the Core Fire Detectors
AMM 26-12-17-000-041
Removal of the Core Fire Detectors
AMM 26-12-17-000-802
Removal of the Forward Fire/Overheat Detector
AMM 26-12-17-000-803
Removal of the Aft Fire/Overheat Detector
AMM 26-12-17-400-040
Installation of the Core Fire Detectors
AMM 26-12-17-400-041
Installation of the Core Fire Detectors
AMM 26-12-17-400-802
Installation of the Forward Fire/Overheat Detector
AMM 26-12-17-400-803
Installation of the Aft Fire/Overheat 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
AWM 715175
3. Fault Confirmation
Subtask 26-12-00-710-062-A
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 26-12-00-810-212-B ** ON A/C NOT FOR ALL
A. If the test confirms the fault:
   (1) Do a visual inspection of the:
  • Engine-2-pylon loop-A fire-detector (3WD2),
  • Core-ventilation loop-A fire-detector (4001WD1)
  • Core-AGB loop-A fire-detector (4002WD1)
  • Engine-2-pylon fire-detector harnesses (31WD2) and (32WD2), AMM 26-12-00-200-802.
     (a) If one or more fire detector(s) is (are) damaged:
     (b) If there is no visual damage:
  • Do the trouble shooting given in Para 4.B.
Subtask 26-12-00-810-057-A ** ON A/C NOT FOR ALL
B. If the test gives the two maintenance messages CHECK ENG 2 FIRE LOOP A and CHECK ENG 2 FIRE LOOP B:
  • Disconnect the connectors 2WD2-A and 2WD2-B from the engine 2 FDU (2WD2).
  • On each of these connectors, on the wiring side, make sure that the equivalent resistance value between pins J and K is between 1425 ohms and 1575 ohms ASM 261201.
   (1) If the equivalent resistance value on the loops A and B is not correct and is:
. Between 2137 ohms and 2363 ohms: there is one defective detector.
. Between 4275 ohms and 4725 ohms: there are two defective detectors.
. Infinite: there is either three defective detectors or defective wiring.
     (a) If the equivalent resistance value is not correct:
       1 If one or more fire detector(s) is (are) damaged:
       2 If there is no visual damage:
  • Disconnect the electrical harness from each engine 2 fire detector.
  • On the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms ASM 261201:
    . Between pins A and D for the engine 2 pylon A fire detector (3WD2), engine 2 pylon B fire detector (4WD2), fan loop A fire detector (4000WD1) and fan loop B fire detector (4000WD2)
    . Between pins A and C for the core loop A fire detector (4001WD1) and fan loop B fire detector (4001WD2).
         a If the resistance value is not correct:
         b If the resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P (LOOP A) and (LOOP B) from the engine 2 FDU (2WD2) to the three loop A and B fire detectors ASM 261201.
   (2) If the equivalent resistance value is correct on one loop and not on the other.
     (a) For the loop with the incorrect resistance value:
       1 If one or more fire detector(s) is (are) damaged:
       2 If there is no visual damage:
  • Disconnect the electrical harness from each engine 2 fire detector.
  • On the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms ASM 261201:
    . Between pins A and D for the engine 2 pylon A fire detector (3WD2) or engine 2 pylon B fire detector (4WD2), fan loop A fire detector (4000WD1) or fan loop B fire detector (4000WD2)
    . Between pins A and C for the core loop A fire detector (4001WD1) and fan loop B fire detector (4001WD2).
         a If the resistance value is not correct:
         b If the resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P from the engine 2 FDU (2WD2) to the three loop fire detectors ASM 261201.
     (b) For the loop with the correct resistance value:
  • Disconnect the electrical harness from the three fire detectors.
  • To do the insulation of the fire detector, refer to the table below for the correct voltage values.
P/N
Voltage to apply
S700Y0883 (7101-05-1050-575-9)
S702Y0420 (8862-01-1150-707-9)
S702Y0443 (8862-101-1150-707-9)
250 VDC Max
7827-03, 7827-02
S700Y0840 (5421-10-932-430-8)
S702Y0202 (5421-14-932-430-8)
7702-02, 7702-03, 7702-04
250 VDC
473873-2, 473873-8
10-1050
N/A
12134-00
3601-91
45 VDC
  • On the responder of each detector, make sure that the insulation resistance value is higher than 20 Megohms ASM 261201:
    . Between pins A and the responder metal casing and between pin D and the responder metal casing for the engine 2 pylon A fire detector (3WD2) or engine 2 pylon B fire detector (4WD2), fan loop A fire detector (4000WD1) or fan loop B fire detector (4000WD2)
    . Between pin A and the responder metal casing and between pin C and the responder metal casing for the core loop A fire detector (4001WD1) and fan loop B fire detector (4001WD2).
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P from the engine 2 FDU (2WD2) to the three loop fire detectors ASM 261201.
   (3) If the equivalent resistance values are correct on the loops A and B:
     (a) If the fault continues:
  • Disconnect the electrical harness from the three loop A and B fire detectors.
  • To do the insulation of the fire detector, refer to the table below for the correct voltage values.
P/N
Voltage to apply
S700Y0883 (7101-05-1050-575-9)
S702Y0420 (8862-01-1150-707-9)
S702Y0443 (8862-101-1150-707-9)
250 VDC Max
7827-03, 7827-02
S700Y0840 (5421-10-932-430-8)
S702Y0202 (5421-14-932-430-8)
7702-02, 7702-03, 7702-04
250 VDC
473873-2, 473873-8
10-1050
N/A
12134-00
3601-91
45 VDC
  • On the responder of each detector, make sure that the insulation resistance value is higher than 20 Megohms ASM 261201:
    . Between pins A and the responder metal casing and between pin D and the responder metal casing for the engine 2 pylon A fire detector (3WD2), engine 2 pylon B fire detector (4WD2), fan loop A fire detector (4000WD1) and fan loop B fire detector (4000WD2)
    . Between pin A and the responder metal casing and between pin C and the responder metal casing for the core loop A fire detector (4001WD1) and fan loop B fire detector (4001WD2).
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P (LOOP A) and (LOOP B) from the engine 2 FDU (2WD2) to the three loop A and B fire detectors ASM 261201.
Subtask 26-12-00-810-057-F ** ON A/C NOT FOR ALL
B. If the test gives the maintenance messages CHECK ENG 2 FIRE LOOP A + LOOP B:
  • Disconnect the connectors 2WD2-A and 2WD2-B from the engine 2 FDU (2WD2).
  • On each of these connectors, on the wiring side, make sure that the equivalent resistance value between pins J and K is between 1425 ohms and 1575 ohms ASM 261201.
   (1) If the equivalent resistance value on the loops A and B is not correct and is:
. Between 2137 ohms and 2363 ohms: there is one defective detector.
. Between 4275 ohms and 4725 ohms: there are two defective detectors.
. Infinite: there are three defective detectors or a defective wiring.
     (a) If the equivalent resistance value is not correct:
       1 If one or more fire detector(s) is (are) damaged:
       2 If there is no visual damage:
  • Disconnect the electrical harness from each engine 2 fire detector.
  • On the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms ASM 261201:
    . Between pins A and D for the engine 2 pylon A fire-detector (3WD2), engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) and fan loop B fire-detector (4000WD2)
    . Between pins A and C for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
         a If the resistance value is not correct:
         b If the resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P (LOOP A) and (LOOP B) from the engine 2 FDU (2WD2) to the three loop A and B fire detectors ASM 261201.
   (2) If the equivalent resistance value is correct on one loop and not on the other:
     (a) For the loop with the incorrect resistance value:
       1 If one or more fire detector(s) is (are) damaged:
       2 If there is no visual damage:
  • Disconnect the electrical harness from each engine 2 fire detector.
  • On the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms ASM 261201:
    . Between pins A and D for the engine 2 pylon A fire-detector (3WD2) or engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) or fan loop B fire-detector (4000WD2)
    . Between pins A and C for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
         a If the resistance value is not correct:
         b If the resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P from the engine 2 FDU (2WD2) to the three loop fire detectors ASM 261201.
     (b) For the loop with the correct resistance value:
  • Disconnect the electrical harness from the three fire detectors.
  • To do the insulation of the fire detector, refer to the table below for the correct voltage values.
P/N
Voltage to apply
S700Y0883 (7101-05-1050-575-9)
S702Y0420 (8862-01-1150-707-9)
S702Y0443 (8862-101-1150-707-9)
250 VDC Max
7827-03, 7827-02
S700Y0840 (5421-10-932-430-8)
S702Y0202 (5421-14-932-430-8)
7702-02, 7702-03, 7702-04
250 VDC
473873-2, 473873-8
10-1050
N/A
12134-00
3601-91
45 VDC
  • On the responder of each detector, make sure that the insulation resistance value is higher than 20 Megohms ASM 261201:
    . Between pins A and the responder metal casing and between pin D and the responder metal casing for the engine 2 pylon A fire-detector (3WD2) or engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) or fan loop B fire-detector (4000WD2)
    . Between pin A and the responder metal casing and between pin C and the responder metal casing for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P from the engine 2 FDU (2WD2) to the three loop fire detectors ASM 261201.
   (3) If the equivalent resistance values are correct on the loops A and B:
     (a) If the fault continues:
  • Disconnect the electrical harness from the three loop A and B fire detectors.
  • To do the insulation of the fire detector, refer to the table below for the correct voltage values.
P/N
Voltage to apply
S700Y0883 (7101-05-1050-575-9)
S702Y0420 (8862-01-1150-707-9)
S702Y0443 (8862-101-1150-707-9)
250 VDC Max
7827-03, 7827-02
S700Y0840 (5421-10-932-430-8)
S702Y0202 (5421-14-932-430-8)
7702-02, 7702-03, 7702-04
250 VDC
473873-2, 473873-8
10-1050
N/A
12134-00
3601-91
45 VDC
  • On the responder of each detector, make sure that the insulation resistance value is higher than 20 Megohms ASM 261201:
    . Between pins A and the responder metal casing and between pin D and the responder metal casing for the engine 2 pylon A fire-detector (3WD2), engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) and fan loop B fire-detector (4000WD2)
    . Between pin A and the responder metal casing and between pin C and the responder metal casing for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P (LOOP A) and (LOOP B) from the engine 2 FDU (2WD2) to the three loop A and B fire detectors ASM 261201.
Subtask 26-12-00-810-057-H ** ON A/C NOT FOR ALL
B. If the test gives the maintenance messages CHECK ENG 2 FIRE LOOP A + LOOP B:
  • Disconnect the connectors 2WD2-A and 2WD2-B from the engine 2 FDU (2WD2).
  • On each of these connectors, on the wiring side, make sure that the equivalent resistance value between pins J and K is between 1425 ohms and 1575 ohms ASM 261201.
   (1) If the equivalent resistance value on the loops A and B is not correct and is:
. Between 2137 ohms and 2363 ohms: there is one defective detector.
. Between 4275 ohms and 4725 ohms: there are two defective detectors.
. Infinite: there are three defective detectors or a defective wiring.
     (a) If the equivalent resistance value is not correct:
       1 If one or more fire detector(s) is (are) damaged:
       2 If there is no visual damage:
  • Disconnect the electrical harness from each engine 2 fire detector.
  • On the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms ASM 261201:
    . Between pins A and D for the engine 2 pylon A fire-detector (3WD2), engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) and fan loop B fire-detector (4000WD2)
    . Between pins A and C for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
         a If the resistance value is not correct:
         b If the resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P (LOOP A) and (LOOP B) from the engine 2 FDU (2WD2) to the three loop A and B fire detectors ASM 261201.
   (2) If the equivalent resistance value is correct on one loop and not on the other:
     (a) For the loop with the incorrect resistance value:
       1 If one or more fire detector(s) is (are) damaged:
       2 If there is no visual damage:
  • Disconnect the electrical harness from each engine 2 fire detector.
  • On the responder of each fire detector, make sure that the resistance value is between 4275 ohms and 4725 ohms ASM 261201:
    . Between pins A and D for the engine 2 pylon A fire-detector (3WD2) or engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) or fan loop B fire-detector (4000WD2)
    . Between pins A and C for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
         a If the resistance value is not correct:
         b If the resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P from the engine 2 FDU (2WD2) to the three loop fire detectors ASM 261201.
     (b) For the loop with the correct resistance:
  • Disconnect the electrical harness from the three fire detectors.
  • To do the insulation of the fire detector, refer to the table below for the correct voltage values.
P/N
Voltage to apply
S700Y0883 (7101-05-1050-575-9)
S702Y0420 (8862-01-1150-707-9)
S702Y0443 (8862-101-1150-707-9)
250 VDC Max
7827-03, 7827-02
S700Y0840 (5421-10-932-430-8)
S702Y0202 (5421-14-932-430-8)
7702-02, 7702-03, 7702-04
250 VDC
473873-2, 473873-8
10-1050
N/A
12134-00
3601-91
45 VDC
  • On the responder of each detector, make sure that the insulation resistance value is higher than 20 Megohms ASM 261201:
    . Between pins A and the responder metal casing and between pin D and the responder metal casing for the engine 2 pylon A fire-detector (3WD2) or engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) or fan loop B fire-detector (4000WD2)
    . Between pin A and the responder metal casing and between pin C and the responder metal casing for the core loop A fire-detector (4001WD1) or fan loop B fire-detector (4001WD2).
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P from the engine 2 FDU (2WD2) to the three loop fire detectors ASM 261201.
   (3) If the equivalent resistance values are correct on the loop A and B:
     (a) If the fault continues:
  • Disconnect the electrical harness from the three loop A and B fire detectors.
  • To do the insulation of the fire detector, refer to the table below for the correct voltage values.
P/N
Voltage to apply
S700Y0883 (7101-05-1050-575-9)
S702Y0420 (8862-01-1150-707-9)
S702Y0443 (8862-101-1150-707-9)
250 VDC Max
7827-03, 7827-02
S700Y0840 (5421-10-932-430-8)
S702Y0202 (5421-14-932-430-8)
7702-02, 7702-03, 7702-04
250 VDC
473873-2, 473873-8
10-1050
N/A
12134-00
3601-91
45 VDC
  • On the responder of each detector, make sure that the insulation resistance value is higher than 20 Megohms ASM 261201:
    . Between pins A and the responder metal casing and between pin D and the responder metal casing for the engine 2 pylon A fire-detector (3WD2), engine 2 pylon B fire-detector (4WD2), fan loop A fire-detector (4000WD1) and fan loop B fire-detector (4000WD2)
    . Between pin A and the responder metal casing and between pin C and the responder metal casing for the core loop A fire-detector (4001WD1) and fan loop B fire-detector (4001WD2).
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
  • Do a check and repair the wiring of the FIRE DET I/P (LOOP A) and (LOOP B) from the engine 2 FDU (2WD2) to the three loop A and B fire detectors ASM 261201.
Subtask 26-12-00-810-057-J ** ON A/C NOT FOR ALL
B. If the test confirms the fault:
  • Disconnect connector 2WD2-A from the engine 2 FDU (2WD2).
  • On the connector, on the wiring side, do a check of the equivalent resistance value between pins A/J and A/K, ASM 261201.
   (1) If the resistance value is between 3078 ohms and 3402 ohms:
  • Do a check of the wiring between the engine-2-pylon loop-A fire-detector (3WD2) and the first terminal block, AWM 261206.
     (a) If the wiring is not correct:
  • Disconnect the engine-2-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/A and A/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 engine-2-pylon fire-detector harnesses (31WD2) and (32WD2), AWM 261206.

         a If there is no continuity:
         b If there is continuity:
  • Do a check and repair the wiring between first terminal-block and the engine-2-pylon fire-detector harnesses (31WD2) and (32WD2), AWM 261206.
  • Connect the engine-2-pylon fire-detector harnesses (31WD2) and (32WD2) to the engine-2-pylon loop-A fire-detector (3WD2).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).

     (b) If the wiring is correct:
  • Connect the engine-2-pylon fire-detector harnesses (31WD2) and (32WD2) to the engine-2-pylon loop-A fire-detector (3WD2).
  • Do a check of the wiring between the first terminal-block and the core-AGB loop-A fire-detector (4002WD1), AWM 715175.
       1 If the wiring is not correct:
  • Repair it.
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
       2 If the wiring is correct:
         a If the fault continues:
   (2) If the resistance value is between 4275 ohms and 4725 ohms:
  • Do a check of the wiring between, AWM 261206 and AWM 715175:
    . Pin A/C of the core-ventilation loop-A fire-detector (4001WD1) and the first terminal-block
    . Pin A/A of the core-ventilation loop-A fire-detector (4001WD1) and the first terminal-block
    . Pin A/C of the core-AGB loop-A fire-detector (4002WD1) and the first terminal-block
    . Pin A/A of the core-AGB loop-A fire-detector (4002WD1) and the first terminal-block.
     (a) If the wiring is not correct:
  • Replace it (them).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
     (b) If the wiring is correct:
   (3) If the resistance value is between 6469.5 ohms and 7150.5 ohms:
  • Do a check of the wiring between the engine-2-pylon loop-A fire-detector (3WD2) and the first terminal-block, AWM 261206.
     (a) If the wiring is not correct:
  • Disconnect the engine-2-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/A and A/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 engine-2-pylon fire-detector harnesses (31WD2) and (32WD2), AWM 261206.

         a If there is no continuity:
         b If there is continuity:
  • Do a check and repair the wiring between the first terminal-block and the engine-2-pylon fire-detector harnesses (31WD2) and (32WD2), AWM 261206.
  • Connect the engine-2-pylon fire-detector harnesses (31WD2) and (32WD2) to the engine-2-pylon loop-A fire-detector (3WD2).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).

     (b) If the wiring is correct:
  • Connect the engine-2-pylon fire-detector harnesses (31WD2) and (32WD2) to the engine-2-pylon loop-A fire-detector (3WD2).
  • Do a check of the wiring between the first terminal-block and the core-ventilation loop-A fire-detector (4001WD1), AWM 261206 and AWM 715175.
       1 If the wiring is not correct:
  • Repair it.
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
       2 If the wiring is correct:
         a If the fault continues:
   (4) If the resistance value is infinite:
     (a) Do a check of the wiring between, AWM 261206:
  • Pin A/K of the connector 2WD2-A and the first terminal-block
  • Pin A/J of the connector 2WD2-A and the first terminal-block.
       1 If the wiring is not correct:
  • Repair it (them).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
       2 If the wiring is correct:
  • Do a check of the wiring between, ASM 261201:
    . Pin A/K of the connector 2WD2-A and pin A/C of the core-ventilation loop-A fire-detector (4001WD1)
    . Pin A/J of the connector 2WD2-A and pin A/A of the core-ventilation loop-A fire-detector (4001WD1)
    . Pin A/K of the connector 2WD2-A and pin A/C of the AGB loop-A fire-detector (4002WD1)
    . Pin A/J of the connector 2WD2-A and pin A/A of the AGB loop-A fire-detector (4002WD1)
    . Pin A/K of the connector 2WD2-A and pin A/C of the engine-2-pylon loop-A fire-detector (3WD2)
    . Pin A/J of the connector 2WD2-A and pin A/A of the engine-2-pylon loop-A fire-detector (3WD2).
         a If the wiring is not correct:
  • Repair it (them).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
         b If the wiring is correct:
   (5) If the resistance value is between 225 ohms and 1312.1 ohms:
  • Do a visual check for water on all the connections:
     (a) If there is water:
  • Clean the connection(s).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
     (b) If there is no water:
  • On the responder of the engine-2-pylon loop-A fire-detector (3WD2), apply 45VDC voltage and make sure that the insulation resistance value is more than 100 Mohms.
       1 If the insulation resistance value is not correct:
       2 If the insulation resistance value is correct:
         a On the responders of the core-AGB loop-A fire-detector (4002WD1) and of the core-ventilation loop-A fire-detector (4001WD1), apply voltage between 15VDC and 28VDC and make sure that the insulation resistance value is more than 100 Mohms:
   (6) If the resistance value is between 0 ohms and 178 ohms:
  • On the responders, do a check of the equivalent resistance value between, ASM 261201:
    . Pin A/C and A/A of the core-ventilation loop-A fire-detector (4001WD1)
    . Pin A/C and A/A of the core-AGB loop-A fire-detector (4002WD1)
    . Pin A/C and A/A of the engine-2-pylon loop-A fire-detector (3WD2).
     (a) If the resistance values are null:
     (b) If the resistance values are corrects:
  • Do a check of the wiring between, ASM 261201:
    . Pin A/C of the core-ventilation loop-A fire-detector (4001WD1) and the first terminal-block
    . Pin A/A of the core-ventilation loop-A fire-detector (4001WD1) and the first terminal-block
    . Pin A/C of the core-AGB loop-A fire-detector (4002WD1) and the first terminal-block
    . Pin A/A of the core-AGB loop-A fire-detector (4002WD1) and the first terminal-block
    . Pin A/C of the engine-2-pylon loop-A fire-detector (3WD2) and the first terminal-block
    . Pin A/A of the engine-2-pylon loop-A fire-detector (3WD2) and the first terminal-block.
       1 If the wiring is not correct:
  • Repair it (them).
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
       2 If the wiring is correct:
  • Replace the terminal-block .
  • Connect connector 2WD2-A to the engine 2 FDU (2WD2).
Subtask 26-12-00-710-063-A ** ON A/C NOT FOR ALL
C. Do the test given in Para. 3.
Subtask 26-12-00-810-206-A ** ON A/C NOT FOR ALL
D. For the fault message related to engine-2 loop B, refer to the (Ref. TSM TASK 26-12-00-810-806).
[Rev.8 from Aug 2018] 2026.04.04 04:27:07 UTC
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