W DOC AIRBUS | TSM A320F

IDG 1(2) Oil Overheating

TASK 28-16-00-810-801-A
IDG 1(2) Oil Overheating

WARNING: OBEY THE FUEL SAFETY PROCEDURES.
WARNING: WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
1. Possible Causes
  • SENSOR-TEMP, LEFT WING TK OUTER CHANNEL A [30QJ1]
  • SENSOR-TEMP, RIGHT WING TK OUTER CHANNEL A [30QJ2]
  • SENSOR-TEMP, LEFT WING TK INNER CHANNEL A or SENSOR-TEMP, LEFT WING TK INNER CHANNEL A [29QJ1]
  • SENSOR-TEMP, RIGHT WING TK INNER CHANNEL A or SENSOR-TEMP, RIGHT WING TK INNER CHANNEL A [29QJ2]
  • SENSOR-LOW LEVEL, LEFT WING TK INNER CHANNEL A [38QJ1]
  • SENSOR-LOW LEVEL, RIGHT WING TK INNER CHANNEL A [38QJ2]
  • SENSOR-HIGH LVL, LEFT WING SURGE TK CHANNEL A [28QJ1]
  • SENSOR-HIGH LVL, RIGHT WING SURGE TK CHANNEL A [28QJ2]
  • FLSCU-1 [7QJ]
  • FLSCU-2 [9QJ]
  • EGIU-1 [22XU1]
  • EGIU-2 [22XU2]
  • GCU-1 [1XU1]
  • GCU-2 [1XU2]
  • Fuel Return Valve (FRV)
  • aircraft wiring
  • CHECK VALVE-FUEL RECIRCULATION, L [122QM]
  • CHECK VALVE-FUEL RECIRCULATION, R [123QM]
  • VALVE-PRESSURE HOLDING, L WING TANK [124QM]
  • VALVE-PRESSURE HOLDING, R WING TANK [125QM]
  • fuel recirculation (cooling) pipe
  • VALVE-PRESSURE HOLDING [218QM]
  • VALVE-PRESSURE HOLDING [219QM]
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
MULTIMETER - STANDARD
 B. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 24-21-00-810-818-A
Loss of the IDG1 Temperature Indication
TSM TASK 24-21-00-810-819-A
Loss of the IDG2 Temperature Indication
TSM TASK 28-46-00-810-812-A
L(R) Surge Tank Overflow Sensor 28QJ1(2)
TSM TASK 28-46-00-810-813-A
L(R) Inner Temperature Sensor 29QJ1(2)
TSM TASK 28-46-00-810-814-A
L(R) Outer Temperature Sensor 30QJ1(2)
TSM TASK 28-46-00-810-815-A
L(R) IDG Shut Off Sensor 38QJ1(2)
TSM TASK 28-46-00-810-818-A
FLSCU1(2) 7QJ(9QJ)
AMM 12-11-28-650-003
Pressure Refuel with Automatic Control
AMM 12-11-28-650-004
Pressure Refuel with Manual Control
AMM 24-21-00-710-040
Operational Test of the IDG Disconnect and Reconnect (Reset) Function - Engine Static
AMM 28-00-00-000-001
Removal of the Fuel Pipes
AMM 28-00-00-400-001
Installation of the Fuel Pipes
AMM 28-16-00-710-002
Operational Check of Fuel Recirculation Check Valve to Ensure Valve not Failed Open
ASM 281601
AMM 28-16-41-000-001
Removal of the Pressure-Holding Valve
AMM 28-16-41-400-001
Installation of the Pressure-Holding Valve
AMM 28-16-42-000-001
Removal of the Fuel Recirculation Check-valve
AMM 28-16-42-400-001
Installation of the Fuel Recirculation Check-valve
AMM 28-16-43-000-001
Removal of the Pressure Holding Valve
AMM 28-16-43-400-001
Installation of the Pressure Holding Valve
AWM 282107
AMM 28-46-34-000-001
Removal of the Fuel-Level Sensing Control-Unit (FLSCU)
AMM 28-46-34-400-001
Installation of the Fuel-Level Sensing Control-Unit (FLSCU)
AMM 31-60-00-860-001
EIS Start Procedure
AMM 71-00-00-710-006
Minimum Idle Check
AMM 73-11-50-000-002
Removal of the Fuel Return Valve (FRV)
AMM 73-11-50-360-002
Leak Check and Functional Test of the Fuel Return Valve
AMM 73-11-50-400-002
Installation of the Fuel Return Valve
AMM 73-25-34-000-040
Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-040
Installation of the Engine Interface Unit (EIU)
3. Fault Confirmation
Subtask 28-16-00-865-050-A
A. Table of the circuit breakers referred to in this procedure:
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
121VUFUEL/CTR TK/PUMPS1 AND 2/CTL AND IND32QAR26
121VUFUEL/CTR TK/PUMPS1 AND 2/CTL AND IND31QAR25
** ON A/C ALL
121VUFUEL/PUMPS/2/R CTL AND L IND10QAR29
121VUFUEL/PUMPS/1/L CTL AND R IND3QAR23
** ON A/C NOT FOR ALL
121VUFUEL/CTR TK/L&R XFR/CTL & IND2QLR26
121VUFUEL/CTR TK/L&R XFR/CTL & IND1QLR25
Subtask 28-16-00-710-050-B ** ON A/C NOT FOR ALL
B. Test
   (1) Do a check of the MAINTENANCE POST FLIGHT REPORT (PFR) for the ECAM WARNING MESSAGES that follow:
  • FUEL L(R) TK PUMP 1 LO PR
  • FUEL L(R) TK PUMP 2 LO PR
  • FUEL CTR TK PUMP 1(2) LO PR
  • FUEL X FEED VALVE FAULT.
   (2) Do a check of the PFR for the FAULT MESSAGES that follow:
  • 24-21-51 IDG1(2) (OVERTEMP) or any other IDG related message
  • 28-46-15 FUEL LEVEL SENSING L(R) LO LEVEL SENSOR 38QJ1(2)
  • 28-46-16 FUEL LEVEL SENSING L(R) SURGE SENSOR 28QJ1(2)
  • 28-46-17 FUEL LEVEL SENSING L(R) INN TEMP SENSOR 29QJ1(2)
  • 28-46-17 FUEL LEVEL SENSING L(R) OUT TEMP SENSOR 30QJ1(2)
  • 28-46-34 FUEL LEVEL SENSING FLSCU 1(2) 7QJ(9QJ).
NOTE: Failure of the sensors may not be shown in the fault message as a sensor fault. But the failure of a sensor could be shown by a failure of the FLSCU 1(2) 7QJ(9QJ).
   (3) If any warnings (listed in step (1)) and/or messages (listed in step (2)) are shown, time correlate the warnings and messages as applicable.
   (4) Go to the applicable ATA Chapter with these fault symptoms (warnings and/or messages). Do the trouble shooting procedure related to the failure message before you continue with more steps:
   (5) If necessary reconnect the applicable IDG 1(2) AMM 24-21-00-710-040.
   (6) Make sure that the C/Bs that follow are closed:
  • C/B-FUEL/CTR TK/PUMPS 1 AND 2/CTL AND IND (31QA)
  • C/B-FUEL/CTR TK/PUMPS 1 AND 2/CTL AND IND (32QA).
NOTE: If the related DC BUS is not powered and the C/Bs not closed the applicable FLSCU cannot issue/supply an IDG/FRV open command. This is because a FLSCU will give a false CLOSE IDG/FRV output when it is not powered (de-energized condition).
   (7) Do the EIS Start Procedure (ECAM only) AMM 31-60-00-860-001.
   (8) On the ECAM control panel, push (in) the FUEL P/BSW.
   (9) Make sure that the FUEL page shows on the ECAM lower Display Unit (DU).
   (10) Monitor the FUEL system display (lower ECAM DU) and make sure that:
  • all the fuel pumps are shown green in-line
  • the outer cell temperature is less than 55 deg C
  • the inner cell temperature is less than 52.5 deg C
  • the inner cell contains more than 270 kg (595.2479 lb) of fuel (IDG Shut Off Sensor 38QJ1(2) wet) refuel if necessary AMM 12-11-28-650-003 or AMM 12-11-28-650-004
  • the Crossfeed Valve is open.
NOTE: These fuel conditions will let the IDG cooler fuel be returned to the related wing tank if necessary.
   (11) Do the power plant Minimum Idle Check AMM 71-00-00-710-006.
   (12) On the ECAM control panel, push (in) the ELECT P/BSW.
   (13) On the ELECT system display (lower ECAM DU), monitor the IDG 1 and IDG 2 oil temperatures.
   (14) If any of IDG conditions that follow are shown, go to Para. 4.A:
  • an IDG 1(2) OIL OVHT message, and
  • the IDG 1(2) Oil Temperature shows pulsing green (more than the specified limit), or
  • the IDG 1(2) Oil Temperature shows amber (high), or
   (15) If the IDG 1(2) Oil Temperature is more than IDG 2(1) and there is no ATA 24 maintenance message:
NOTE: The difference between these values can be caused by a fault in the EGIU-1 [22XU1] ( EGIU-2 [22XU2] ) or GCU-1 [1XU1] ( GCU-2 [1XU2] ).
     (a) Do the Fault Isolation steps in the trouble shooting procedure:
     (b) If the fault continues, go to Para. 4.A.
Subtask 28-16-00-710-050-C ** ON A/C NOT FOR ALL
B. Test
   (1) Do a check of the MAINTENANCE POST FLIGHT REPORT (PFR) for the ECAM WARNING MESSAGES that follow:
  • FUEL L(R) TK PUMP 1 LO PR
  • FUEL L(R) TK PUMP 2 LO PR
  • FUEL X FEED VALVE FAULT.
   (2) Do a check of the PFR for the FAULT MESSAGES that follow:
  • 24-21-51 IDG1(2) (OVERTEMP) or any other IDG related message
  • 28-46-15 FUEL LEVEL SENSING L(R) LO LEVEL SENSOR 38QJ1(2)
  • 28-46-16 FUEL LEVEL SENSING L(R) SURGE SENSOR 28QJ1(2)
  • 28-46-17 FUEL LEVEL SENSING L(R) INN TEMP SENSOR 29QJ1(2)
  • 28-46-17 DUMMY TEMP SENSOR 41QJ
  • 28-46-17 DUMMY TEMP SENSOR 42QJ
  • 28-46-34 FUEL LEVEL SENSING FLSCU1 (2) 7QJ(9QJ).
NOTE: Failure of the sensors may not be shown in the fault message as a sensor fault. But the failure of a sensor could be shown by a failure of the FLSCU 1(2) 7QJ(9QJ).
   (3) If any warnings (listed in step (1)) and/or messages (listed in step (2)) are shown, time correlate the warnings and messages as applicable.
   (4) Go to the applicable ATA Chapter with these fault symptoms (warnings and/or messages). Do the trouble shooting procedure related to the failure message before you continue with more steps:
   (5) If necessary reconnect the applicable IDG 1(2) AMM 24-21-00-710-040.
   (6) Make sure that the C/Bs that follow are closed:
  • C/B-FUEL/CTR TK/L & R XFR/CTL & IND (1QL)
  • C/B-FUEL/CTR TK/L & R XFR/CTL & IND (2QL).
NOTE: If the related DC BUS is not powered and the C/Bs not closed the applicable FLSCU cannot issue/supply an IDG/FRV open command. This is because a FLSCU will give a false CLOSE IDG/FRV output when it is not powered (de-energized condition).
   (7) Do the EIS Start Procedure (ECAM only) AMM 31-60-00-860-001.
   (8) On the ECAM control panel, push (in) the FUEL P/BSW.
   (9) Make sure that the FUEL page shows on the ECAM lower Display Unit (DU).
   (10) Monitor the FUEL system display (lower ECAM DU) and make sure that:
  • all the fuel pumps are shown green in-line
  • the L (R) inner wing temperature is less than 52.5 deg C
  • the L (R) wing tank contains more than 290 kg (639.3404 lb) of fuel to make sure that the IDG Shut Off Sensor 38QJ1(2) is wet refuel if necessary AMM 12-11-28-650-003 or AMM 12-11-28-650-004
  • the Crossfeed Valve is open.
NOTE: These fuel conditions will let the IDG cooler fuel be returned to the related wing tank if necessary.
   (11) Do the power plant Minimum Idle Check AMM 71-00-00-710-006.
   (12) On the ECAM control panel, push (in) the ELECT P/BSW.
   (13) On the ELECT system display (lower ECAM DU), monitor the IDG 1 and IDG 2 oil temperatures.
   (14) If any of IDG conditions that follow are shown, go to Para. 4.A:
  • an IDG 1(2) OIL OVHT message, and
  • the IDG 1(2) Oil Temperature shows pulsing green (more than the specified limit), or
  • the IDG 1(2) Oil Temperature shows amber (high), or
  • the IDG 1(2) Oil Temperature is more than IDG 2(1), but is less than the high limit.
   (15) If the IDG 1(2) Oil Temperature is more than IDG 2(1) and there is no ATA 24 maintenance message:
NOTE: The difference between these values can be caused by a fault in the [22XU1] ( [22XU2] ) or GCU-1 [1XU1] ( GCU-2 [1XU2] ).
     (a) Do the Fault Isolation steps in the trouble shooting procedure:
     (b) If the fault continues, go to Para. 4.A.
4. Fault Isolation
Subtask 28-16-00-810-050-B ** ON A/C NOT FOR ALL
A. Procedure
   (1) If the failure is related to IDG-1, remove the Engine Interface Unit (EIU) 1KS1 AMM 73-25-34-000-040.
   (2) If the failure is related to IDG-2, remove the EIU 1KS2 AMM 73-25-34-000-040.
   (3) Use a MULTIMETER - STANDARD, to do a test ASM 281601 to see if there is a ground at the EIU rack connector 1KS1(2)-AA, pin 2A.
NOTE: This step checks the input to the EIU, of the fuel logic for the IDG cooling, from the related FLSCU-1(2) 7QJ(9QJ).
   (4) If there is a ground on pin 2A of the rack connector 1KS1(2)-AA, go to step (6) (unserviceable).
NOTE: This shows that the EIU does not get an open command, for the Fuel Return Valve (FRV), from the FLSS, 28-46-00.
   (5) If there is no ground on pin 2A of the rack connector 1KS1(2)-AA (serviceable):
NOTE: This is the correct logic output from the FLSS, 28-46-00 for the conditions (inputs) given in Para. 3.B.(10) and will let the FRV open if required.
     (a) Install the EIU 1KS1(1KS2) removed in step (1) or (2) AMM 73-25-34-400-040.
     (b) Do a check of the applicable Fuel Return Valve (FRV) AMM 73-11-50-360-002 and replace, if necessary, AMM 73-11-50-000-002 and AMM 73-11-50-400-002.
     (c) If the fault continues:
       1 Go to Para. 3.B. and do the examination of the fault symptoms again for a possible alternative entry point(s).
       2 Go to Para. 4.B. - Fuel Recirculation (Cooling) Pipe Trouble-shooting.
   (6) Remove the related FLSCU AMM 28-46-34-000-001.
   (7) If the ground seen in step (4):
     (a) Is still shown (with the FLSCU removed):
       1 Do a check of the aircraft wiring (IDG fuel logic output wire) ASM 281601 between:
  • the related FLSCU rack connector AA, pin 4D and the related EIU rack connector AA, pin 2A.
       2 Repair all the unserviceable wiring and connectors.
       3 Install the FLSCU removed in step (6) AMM 28-46-34-400-001.
       4 Do the test given in step (3).
       5 Install the EIU removed in step (1) or (2) AMM 73-25-34-400-040.
       6 Do the test given in Para. 3.B.
     (b) Is not shown (with the FLSCU removed):
       1 Replace the FLSCU-1 [7QJ] ( FLSCU-2 [9QJ] ) with a serviceable item and install AMM 28-46-34-400-001.
       2 Do a check of the aircraft wiring (that is common to FLSCU-1 and FLSCU-2) ASM 281601 and AWM 282107 between:
  • the FLSCU-1 rack connector AA, pin 14C and the FLSCU-2 rack connector AA, pin 14D
  • the FLSCU-1 rack connector AA, pin 14D and the FLSCU-2 rack connector AA, pin 14C
  • the FLSCU-1 rack connector AA, pin 12D and the actuator-crossfeed valve free connector 5QE-A, pin B
  • the FLSCU-2 rack connector AA, pin 12D and the actuator-crossfeed valve free connector 5QE-A, pin B.
       3 For a IDG 1 failure, do a check of the aircraft wiring ASM 281601 and AWM 282107 between:
  • the FLSCU-1 rack connector AA, pin 13C and the PRESS SW-FUEL PUMP No. 1, L WING TK connector 23QA-A, pin C
  • the FLSCU-1 rack connector AA, pin 13D and the PRESS SW-FUEL PUMP No. 2, L WING TK connector 27QA-A, pin C
  • the FLSCU-1 rack connector AA, pin 12C and the PRESS SW-FUEL PUMP No. 1, CTR TK connector 39QA-A, pin C
  • the FLSCU-1 rack connector AA, pin 1D and the C/B-FUEL/CTR TK/PUMP1 AND 2/CTL AND IND (31QA).
       4 For a IDG 2 failure, do a check of the aircraft wiring ASM 281601 and AWM 282107 between:
  • the FLSCU-2 rack connector AA, pin 13C and the PRESS SW-FUEL PUMP No. 1, R WING TK connector 24QA-A, pin C
  • the FLSCU-2 rack connector AA, pin 13D and the PRESS SW-FUEL PUMP No. 2, R WING TK connector 28QA-A, pin C
  • the FLSCU-2 rack connector AA, pin 12C and the PRESS SW-FUEL PUMP No. 2, CTR TK connector 40QA-A, pin C
  • the FLSCU-2 rack connector AA, pin 1D and the C/B-FUEL/CTR TK/PUMP1 AND 2/CTL AND IND (32QA).
       5 Repair all the unserviceable wiring and connectors.
       6 Install the FLSCU removed in step (6) AMM 28-46-34-400-001.
       7 Do the test given in step (3).
       8 Install the EIU removed in step (1) or (2) AMM 73-25-34-400-040.
       9 Do the test given in Para. 3.B.
Subtask 28-16-00-810-059-A ** ON A/C NOT FOR ALL
B. Procedure - Fuel Recirculation (Cooling) Pipe Trouble-shooting
   (1) Do the Operational Test of the Fuel Recirculation Check Valve 122QM (123QM) AMM 28-16-00-710-002.
   (2) If necessary, replace the CHECK VALVE-FUEL RECIRCULATION, L [122QM] ( CHECK VALVE-FUEL RECIRCULATION, R [123QM] ) AMM 28-16-42-000-001 and AMM 28-16-42-400-001.
   (3) If necessary, replace the VALVE-PRESSURE HOLDING, L WING TANK [124QM] ( VALVE-PRESSURE HOLDING, R WING TANK [125QM] ) AMM 28-16-41-000-001 and AMM 28-16-41-400-001.
   (4) Do the test given in Para. 3.B.
   (5) If the fault continues, do a check of the fuel recirculation (cooling) pipe for damage or blockage and replace, if necessary, AMM 28-00-00-000-001 and AMM 28-00-00-400-001.
   (6) Do the test given in Para. 3.B.
Subtask 28-16-00-810-050-C ** ON A/C NOT FOR ALL
C. Procedure
   (1) If the failure is related to IDG-1, remove the Engine Interface Unit (EIU) 1KS1 AMM 73-25-34-000-040.
   (2) If the failure is related to IDG-2, remove the EIU 1KS2 AMM 73-25-34-000-040.
   (3) Use a MULTIMETER - STANDARD, to do a test ASM 281601 to see if there is a ground at the EIU rack connector 1KS1(2)-AA, pin 2A.
NOTE: This step checks the input to the EIU, of the fuel logic for the IDG cooling, from the related FLSCU-1(2) 7QJ(9QJ).
   (4) If there is a ground on pin 2A of the rack connector 1KS1(2)-AA, go to step (6) (unserviceable).
NOTE: This shows that the EIU does not get an open command, for the Fuel Return Valve (FRV), from the FLSS, 28-46-00.
   (5) If there is no ground on pin 2A of the rack connector 1KS1(2)-AA (serviceable):
NOTE: This is the correct logic output from the FLSS, 28-46-00 for the conditions (inputs) given in Para. 3.B.(10) and will let the FRV open if required.
     (a) Install the EIU 1KS1(1KS2) removed in step (1) or (2) AMM 73-25-34-400-040.
     (b) Do a check of the applicable Fuel Return Valve (FRV) AMM 73-11-50-360-002 and replace, if necessary, AMM 73-11-50-000-002 and AMM 73-11-50-400-002.
     (c) If the fault continues:
       1 Go to Para. 3.B. and do the examination of the fault symptoms again for a possible alternative entry point(s).
       2 Go to Para. 4.B. - Fuel Recirculation (Cooling) Pipe Trouble-shooting.
   (6) Remove the related FLSCU AMM 28-46-34-000-001.
   (7) If the ground seen in step (4):
     (a) Is still shown (with the FLSCU removed):
       1 Do a check of the aircraft wiring (IDG fuel logic output wire) ASM 281601 between:
  • the related FLSCU rack connector AA, pin 4D and the related EIU rack connector AA, pin 2A.
       2 Repair all the unserviceable wiring and connectors.
       3 Install the FLSCU removed in step (6) AMM 28-46-34-400-001.
       4 Do the test given in step (3).
       5 Install the EIU removed in step (1) or (2) AMM 73-25-34-400-040.
       6 Do the test given in Para. 3.B.
     (b) Is not shown (with the FLSCU removed):
       1 Replace the FLSCU-1 [7QJ] ( FLSCU-2 [9QJ] ) with a serviceable item and install AMM 28-46-34-400-001.
       2 Do a check of the aircraft wiring (that is common to FLSCU-1 and FLSCU-2) ASM 281601 and AWM 282107 between:
  • the FLSCU-1 rack connector AA, pin 14C and the FLSCU-2 rack connector AA, pin 14D
  • the FLSCU-1 rack connector AA, pin 14D and the FLSCU-2 rack connector AA, pin 14C
  • the FLSCU-1 rack connector AA, pin 12D and the actuator-crossfeed valve free connector 5QE-A, pin B
  • the FLSCU-2 rack connector AA, pin 12D and the actuator-crossfeed valve free connector 5QE-A, pin B.
       3 For a IDG 1 failure, do a check of the aircraft wiring ASM 281601 and AWM 282107 between:
  • the FLSCU-1 rack connector AA, pin 13C and the PRESS SW-FUEL PUMP No. 1, L WING TK connector 23QA-A, pin C
  • the FLSCU-1 rack connector AA, pin 13D and the PRESS SW-FUEL PUMP No. 2, L WING TK connector 27QA-A, pin C
  • the FLSCU-1 rack connector AA, pin 12C and the PRESS SW-FUEL PUMP No. 1, CTR TK connector 39QA-A, pin C
  • the FLSCU-1 rack connector AA, pin 1D and the C/B-FUEL/CTR TK/PUMP1 AND 2/CTL AND IND (31QA).
       4 For a IDG 2 failure, do a check of the aircraft wiring ASM 281601 and AWM 282107 between:
  • the FLSCU-2 rack connector AA, pin 13C and the PRESS SW-FUEL PUMP No. 1, R WING TK connector 24QA-A, pin C
  • the FLSCU-2 rack connector AA, pin 13D and the PRESS SW-FUEL PUMP No. 2, R WING TK connector 28QA-A, pin C
  • the FLSCU-2 rack connector AA, pin 12C and the PRESS SW-FUEL PUMP No. 2, CTR TK connector 40QA-A, pin C
  • the FLSCU-2 rack connector AA, pin 1D and the C/B-FUEL/CTR TK/PUMP1 AND 2/CTL AND IND (32QA).
       5 Repair all the unserviceable wiring and connectors.
       6 Install the FLSCU removed in step (6) AMM 28-46-34-400-001.
       7 Do the test given in step (3).
       8 Install the EIU removed in step (1) or (2) AMM 73-25-34-400-040.
       9 Do the test given in Para. 3.B.
Subtask 28-16-00-810-059-B ** ON A/C NOT FOR ALL
D. Procedure - Fuel Recirculation (Cooling) Pipe Trouble-shooting
   (1) Do a check of and replace, if necessary:
     (a) The CHECK VALVE-FUEL RECIRCULATION, L [122QM] ( CHECK VALVE-FUEL RECIRCULATION, R [123QM] ) AMM 28-16-42-000-001 and AMM 28-16-42-400-001.
     (b) The VALVE-PRESSURE HOLDING [218QM] ( VALVE-PRESSURE HOLDING [219QM] ) AMM 28-16-43-000-001 and AMM 28-16-43-400-001.
   (2) Do the test given in Para. 3.B.
   (3) If the fault continues, do a check of the fuel recirculation (cooling) pipe for damage or blockage. Replace, if necessary AMM 28-00-00-000-001 and AMM 28-00-00-400-001.
   (4) Do the test given in Para. 3.B.
[Rev.8 from Aug 2018] 2026.04.04 04:28:32 UTC
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