W DOC AIRBUS | TSM A320F

APU AUTO SHUTDOWN - REVERSE FLOW, Reverse Flow Condition for min. 6 Seconds (131-9(A))

TASK 49-00-81-810-847-A
APU AUTO SHUTDOWN - REVERSE FLOW, Reverse Flow Condition for min. 6 Seconds (131-9(A))

1. Possible Causes
  • NO LRU FAULT DETECTED
  • blockage of the APU inlet
  • CHECK VALVE-APU BLEED [7260HM]
  • tube of the DIFFERENTIAL PRESSURE TRANSDUCER (P24)
  • tube of the TOTAL PRESSURE TRANSDUCER (P23)
  • DIFFERENTIAL PRESSURE TRANSDUCER (P24)
  • TOTAL PRESSURE TRANSDUCER (P23)
  • SURGE CONTROL VALVE (P18)
  • ELECTRONIC CONTROL BOX [59KD]
  • tube of the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM).
  • tube of the TOTAL PRESSURE TRANSDUCER (8044KM).
  • DIFFERENTIAL PRESSURE TRANSDUCER (8043KM)
  • TOTAL PRESSURE TRANSDUCER (8044KM)
  • SURGE CONTROL VALVE (8058KM)
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
AIR SOURCE 2 BAR (30 PSI) - REGULATED, FILTERED, DRY
No specific
AR
PLUG - BLANKING
 B. Referenced Information
REFERENCE
DESIGNATION
AMM 36-12-51-000-002
Removal of the APU Bleed Check-Valve
AMM 36-12-51-200-001
Remove and Check Auxiliary Power Unit Bleed Check-Valve for Condition
AMM 36-12-51-400-002
Installation of the APU Bleed Check-Valve
AMM 49-00-00-860-008
APU Start by External Power
AMM 49-51-16-000-002
Removal of the Transducer - Differential Pressure (131-9(A))
AMM 49-51-16-400-002
Installation of the Transducer - Differential Pressure (131-9(A))
AMM 49-51-17-000-002
Removal of the Transducer - Total Pressure (131-9(A))
AMM 49-51-17-400-002
Installation of the Transducer - Total Pressure (131-9(A))
AMM 49-51-52-000-003
Removal of the Surge Control Valve (131-9(A))
AMM 49-51-52-400-003
Installation of the Surge Control Valve (131-9(A))
AMM 49-61-34-000-003
Removal of the Electronic Control Box (ECB) (131-9(A))
AMM 49-61-34-400-003
Installation of the Electronic Control Box (ECB) (131-9(A))
3. Fault Confirmation
Subtask 49-00-81-710-184-A ** ON A/C NOT FOR ALL
A. Read-out of ECB Trouble-Shooting Data
   (1) Put the APU MASTER SW to the ON position.
   (2) Get access to the APU SHUTDOWN report.
   (3) Push the '>' adjacent to LRU DATA:
  • the MCDU menu shows
    NO LRU FAULT DETECTED

   (4) Start the APU and apply Bleed Air for 20 seconds, minimum AMM 49-00-00-860-008.
4. Fault Isolation
Subtask 49-00-81-810-128-A ** ON A/C NOT FOR ALL
A. If an APU auto shutdown occurs during the APU operation and the APU SHUTDOWN report gives the maintenance message:

REVERSE FLOW
DP XDCR P24/PT XDCR P23/ SURGE CONTROL VALVE P18

associated with Fault Code Numbers (FCN) 216

  • do a check for blockage of the APU inlet .
   (1) If the fault continues:
     (a) If the test of the APU BLEED CHECK-VALVE (7260HM) fails:
     (b) If the test of the APU BLEED CHECK-VALVE (7260HM) is OK:
  • do a check for damage/contamination of the DIFFERENTIAL PRESSURE TRANSDUCER (P24) and TOTAL PRESSURE TRANSDCER (P23)
    - remove the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (P24) AMM 49-51-16-000-002.
    - remove the tube of the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-000-002.
    - put PLUG - BLANKING in the openings.
    - use a AIR SOURCE 2 BAR (30 PSI) - REGULATED, FILTERED, DRY to remove unwanted materials out of the tubes.
NOTE: It is recommended to use a pressure of 60-90 psig (4.14-6.20 bar) of filtered air or nitrogen to blow the air through the tubes.
- remove the plugs from the openings.
- install the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (P24) AMM 49-51-16-400-002.
- install the tube of the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-400-002.
     (c) If the fault continues:
- replace the DIFFERENTIAL PRESSURE TRANSDUCER (P24) AMM 49-51-16-000-002 and AMM 49-51-16-400-002.
- replace the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-000-002 and AMM 49-51-17-400-002.
     (d) If the fault continues:
- replace the SURGE CONTROL VALVE (P18) AMM 49-51-52-000-003 and AMM 49-51-52-400-003.
     (e) If the fault continues:
- replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.
Subtask 49-00-81-810-128-B ** ON A/C NOT FOR ALL
A. If an APU auto shutdown occurs during the APU operation and the APU SHUTDOWN report gives the maintenance message:

REVERSE FLOW
PRESS XDCRS (8044KM) /(8043KM) / SCV (8058KM)

associated with Fault Code Numbers (FCN) 216

  • do a check for blockage of the APU inlet .
   (1) If the fault continues:
     (a) If the test of the APU BLEED CHECK-VALVE (7260HM) fails:
     (b) If the test of the APU BLEED CHECK-VALVE (7260HM) is OK:
  • do a check for damage/contamination of the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM) and TOTAL PRESSURE TRANSDCER (8044KM).
    - remove the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM). AMM 49-51-16-000-002.
    - remove the tube of the TOTAL PRESSURE TRANSDUCER (8044KM). AMM 49-51-17-000-002.
    - put PLUG - BLANKING in the openings.
    - use a AIR SOURCE 2 BAR (30 PSI) - REGULATED, FILTERED, DRY to remove unwanted materials out of the tubes.
NOTE: It is recommended to use a pressure of 60-90 psig (4.14-6.20 bar) of filtered air or nitrogen to blow the air through the tubes.
- remove the plugs from the openings.
- install the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM) AMM 49-51-16-400-002.
- install the tube of the TOTAL PRESSURE TRANSDUCER (8044KM) AMM 49-51-17-400-002.
     (c) If the fault continues:
- replace the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM) AMM 49-51-16-000-002 and AMM 49-51-16-400-002.
- replace the TOTAL PRESSURE TRANSDUCER (8044KM) AMM 49-51-17-000-002 and AMM 49-51-17-400-002.
     (d) If the fault continues:
- replace the SURGE CONTROL VALVE (8058KM) AMM 49-51-52-000-003 and AMM 49-51-52-400-003.
     (e) If the fault continues:
- replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.
Subtask 49-00-81-710-185-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:34:35 UTC
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