W DOC AIRBUS | TSM A320F

No APU Bleed-Air Pressure, Low or Fluctuating APU Bleed-Air Pressure (with AIDS Support) (131-9)(A))

TASK 49-00-81-810-891-A
No APU Bleed-Air Pressure, Low or Fluctuating APU Bleed-Air Pressure (with AIDS Support) (131-9)(A))

1. Possible Causes
  • IGV ACTUATOR P21
  • APU
  • IGV ACTUATOR 8014KM
  • 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)
  • damage/leakage of the fuel supply and return lines of the SCV
  • 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)
  • LOAD CONTROL VALVE P12
  • LOAD CONTROL VALVE (8050KM)
  • aircraft wiring
  • INLET TEMP SENSOR (P6)
  • INLET TEMP SENSOR (8010KM)
  • STARTER SHUTOFF VALVE (SAV)
  • aircraft bleed system
  • P2 FLOW CTL VALVE [8HB]
  • P1 FLOW CTL VALVE [11HB]
  • blockade of the Pack Heat Exchanger(s)
  • FLOW CTL UNIT - PACK 1 [23HB]
  • FLOW CTL UNIT - PACK 2 [24HB]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 36-12-00-810-804-A
Low Air Pressure in the Right Crossbleed Duct
TSM TASK 49-00-81-810-843-A
APU AUTO SHUTDOWN - INLET OVERHEAT, APU Inlet Temperature higher than Limit (131-9(A))
TSM TASK 49-00-81-810-851-A
Inlet-Guide Vane-Actuator (P21) Fault (131-9(A))
TSM TASK 49-00-81-810-852-A
Pressure-Transducer Fault or ECB internal Fault (131-9(A))
TSM TASK 49-00-81-810-853-A
Differential-Pressure Transducer (P24) Fault (131-9(A))
TSM TASK 49-00-81-810-854-A
Total-Pressure Transducer (P23) Fault (131-9(A))
TSM TASK 49-00-81-810-858-A
IGV-Actuator (P21) Fault (131-9(A))
TSM TASK 49-00-81-810-861-A
Load-Control Valve (P12) Fault (131-9(A))
TSM TASK 49-00-81-810-871-A
Surge Control Valve (P18) Fault (131-9(A))
TSM TASK 49-20-00-810-803-A
APU Inlet-Temperature (T2) Sensor Fault (131-9(A))
AMM 21-51-51-000-001
Removal of the Pack Flow-Control Valve/ Pack Flow-Control Unit
AMM 21-51-51-400-001
Installation of the Pack Flow-Control Valve/ Pack Flow-Control Unit
AMM 21-52-24-000-001
Removal of the Heat Exchanger Unit (From the Aircraft)
AMM 21-52-24-400-001
Installation of the Heat Exchanger Unit (Into the Aircraft)
AMM 31-36-00-740-008
Access to the Parameter Call-Up Menus
AMM 36-11-00-740-001
BITE Test of the BMC 1(2)
AMM 36-12-00-790-001
Leak Test of the APU Bleed-Air Supply-System
AMM 36-12-51-000-001
Removal of the Check Valve
AMM 36-12-51-200-001
Remove and Check Auxiliary Power Unit Bleed Check-Valve for Condition
AMM 36-12-51-400-001
Installation of the Check Valve
AMM 49-00-00-710-009
Self-Test of the ECB
AMM 49-00-00-720-002
APU Performance Parameters
AMM 49-00-00-860-008
APU Start by External Power
AMM 49-00-00-860-009
APU Shutdown by External Power (131-9(A))
AMM 49-11-11-000-004
Removal of the Power Plant (APU) (131-9(A))
AMM 49-11-11-400-004
Installation of the Power Plant (APU) (131-9(A))
AMM 49-23-14-000-001
Removal of the Sensor-APU Inlet Temperature (131-9(A))
AMM 49-23-14-400-001
Installation of the Sensor-APU Inlet Temperature (131-9(A))
AMM 49-23-51-000-004
Removal of the Inlet Guide Vane - Actuator (131-9(A))
AMM 49-23-51-400-004
Installation of the Inlet Guide Vane - Actuator (131-9(A))
AMM 49-51-16-000-002
Removal of the Transducer - Differential Pressure (131-9(A))
AMM 49-51-16-000-004
Removal of the Differential Pressure Tube (131-9(A))
AMM 49-51-16-400-002
Installation of the Transducer - Differential Pressure (131-9(A))
AMM 49-51-16-400-003
Installation of the Differential Pressure Tube (131-9(A))
AMM 49-51-17-000-002
Removal of the Transducer - Total Pressure (131-9(A))
AMM 49-51-17-000-004
Removal of the Total Pressure Tube (131-9(A))
AMM 49-51-17-400-002
Installation of the Transducer - Total Pressure (131-9(A))
AMM 49-51-17-400-003
Installation of the Total Pressure Tube (131-9(A))
AMM 49-51-51-000-004
Removal of the Load Control Valve (131-9(A))
AMM 49-51-51-400-004
Installation of the Load Control Valve (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))
ASM 496104
AMM 49-61-34-000-001
Removal of the Electronic Control Box (ECB) (GTCP 36-300)
AMM 49-61-34-000-003
Removal of the Electronic Control Box (ECB) (131-9(A))
AMM 49-61-34-400-001
Installation of the Electronic Control Box (ECB) (GTCP 36-300)
AMM 49-61-34-400-003
Installation of the Electronic Control Box (ECB) (131-9(A))
ASM 496202
ASM 496204
AMM 71-00-00-710-001
Dry Motoring Check
3. Fault Confirmation
Subtask 49-00-81-710-232-A ** ON A/C NOT FOR ALL
A. Test
   (1) Do the ECB self test AMM 49-00-00-710-009.
NOTE: If the self test of the ECB gives a maintenance message, do the related trouble shooting first before you continue with this test.
   (2) Get access to the AIDS parameters (ALPHA CALL UP) AMM 31-36-00-740-008.
   (3) Start and operate the APU AMM 49-00-00-860-008.
   (4) On overhead panel 35VU, make sure that the APU GEN p/bsw is released (APU GEN off).
   (5) Examine and record the indications of the APU system page on the lower ECAM display unit and the AIDS parameters on the MCDU for the subsequent conditions.
Record the trend of the EGT during change of APU running state.
NOTE: On the MCDU, you can read these AIDS parameters:
  • IGV (APU Inlet Guide-Vane position; parameter 7A.1.130.01),
  • WB (APU Corrected Bleed-Air Flow; parameter 7A.1.123.01),
  • ADW1 (APU Discrete Word - Information regarding APU operating status; parameter 7A.1.37.01),

    AMM 49-00-00-720-002

    . ADW Alpha code = ADW1 for SAGEM FDIMU
    . ADW Alpha code = APUDSW1 for TELEDYNE FDIMU
  • PD (Main Engine Precooler-Inlet Air-Pressure),
    . Parameter 06F.1.143.01 for Engine 1
    . Parameter 06F.2.143.10 for Engine 1
    . Parameter 06F.1.142.01 for Engine 2
    . Parameter 06F.2.142.10 for Engine 2
  • LCIT (APU Inlet Temperature; parameter 7A.1.110.01),
NOTE: On the APU page of the lower ECAM display unit, you can monitor:
  • TAT (Total Air Temperature in deg. C)
  • GLA (APU Generator Load in %)
  • EGT (APU Exhaust Gas Temperature)
  • PT (Bleed PSI, the APU bleed duct pressure in bar)
     (a) APU in RTL (Ready-to-Load) running state:
  • on overhead panel 25VU the blue AVAIL legend in the APU START p/bsw is on;
       1 Record the applicable parameters (Ref. TABLE A).
     (b) APU in 2 pack ECS running state (PACK 1 and 2):
  • on overhead panel 30VU the APU BLEED p/bsw is pushed to ON;
  • on overhead panel 30VU the PACK 1 p/bsw is pushed (OFF legend is off);
  • on overhead panel 30VU the PACK 2 p/bsw is pushed (OFF legend is off);
       1 Record the applicable parameters (Ref. TABLE A).
     (c) APU in MES (Main Engine Start) running state (ENG1):
       1 Do the dry motoring of the engine 1 AMM 71-00-00-710-001;
       2 Record the applicable parameters (Ref. TABLE A).
     (d) APU in MES (Main Engine Start) running state (ENG2):
       1 Do the dry motoring of the engine 2 AMM 71-00-00-710-001;
       2 Record the applicable parameters (Ref. TABLE A).
   (6) Shutdown the APU AMM 49-00-00-860-009.
Subtask 49-00-81-710-250-A ** ON A/C NOT FOR ALL
B. Parameter Values during different APU running states.
TABLE A
-------+-----------------------------------------------------------+-----------
ALPHA ! MODE !
+-----------------+---------------------+-------------------+
CODE ! RTL ! 2 ECS ! MES ! UNIT
-------+-----------------+---------------------+-------------------+-----------
IGV ! 22 ! 44 - 97 (*) ! 91 - 93 ! degrees
-------+-----------------+---------------------+-------------------+-----------
WB ! N/A ! 0.4 - 0.5 ! 0.38 - 0.42 ! kg/sec
-------+-----------------+---------------------+-------------------+-----------
LCIT ! TAT + (1 to 2) ! TAT + (1 to 4) ! TAT + (1 to 8) ! deg.C
-------+-----------------+---------------------+-------------------+-----------
ADW ! 0810A ! 00109 ! 08509 ! digits
-------+-----------------+---------------------+-------------------+----------
PD1/2 ! N/A ! > 14/14 ! > 20/20 ! psig
-------+-----------------+---------------------+-------------------+-----------
PT ! N/A ! > 1.65 ! > 3.5 ! bar
-------+-----------------+---------------------+-------------------+-----------
(*) IGV varies as a function of the LCIT and the Zone Controller inputs.

Subtask 49-00-81-710-250-I ** ON A/C NOT FOR ALL
B. Parameter Values during different APU running states.
TABLE A
-------+-----------------------------------------------------------+-----------
ALPHA ! MODE !
+-----------------+---------------------+-------------------+
CODE ! RTL ! 2 ECS ! MES ! UNIT
-------+-----------------+---------------------+-------------------+-----------
IGV ! 22 ! 44 - 97 (*) ! 91 - 93 ! degrees
-------+-----------------+---------------------+-------------------+-----------
WB ! N/A ! 0.4 - 0.5 ! 0.38 - 0.42 ! kg/sec
-------+-----------------+---------------------+-------------------+-----------
LCIT ! TAT + (1 to 2) ! TAT + (1 to 4) ! TAT + (1 to 8) ! deg.C
-------+-----------------+---------------------+-------------------+-----------
ADW ! 0811A ! 00119 ! 08519 ! digits
-------+-----------------+---------------------+-------------------+----------
PD1/2 ! N/A ! > 14/14 ! > 20/20 ! psig
-------+-----------------+---------------------+-------------------+-----------
PT ! N/A ! > 1.65 ! > 3.5 ! bar
-------+-----------------+---------------------+-------------------+-----------
(*) IGV varies as a function of the LCIT and the Zone Controller inputs.

4. Fault Isolation
Subtask 49-00-81-810-156-A ** ON A/C NOT FOR ALL
A. If the self test gives the maintenance message:

Subtask 49-00-81-810-168-A ** ON A/C NOT FOR ALL
B. If the IGV parameter values are out of range:
  • check that the EGT increase during a mode change (i.e. RTL to ECS).
NOTE: RTL = Ready To Load
   (1) If the EGT does not increase:
  • remove the IGV ACTUATOR P21 AMM 49-23-51-000-004.
  • do a push/pull test on the IGVs to check the IGV movement.
    .make sure that the IGV has a travel range of 1 -0.01 in. or +0.01 in. (25.400 -0.254 mm or +0.254 mm).
    .measure the force of the IGV movement.
     (a) If a force less than 20 lbf (8.8964 daN) is necessary to move the IGVs:
     (b) If a force more than 20 lbf (8.8964 daN) is necessary to move the IGVs or the travel range is different than 1 -0.01 in. or +0.01 in. (25.400 -0.254 mm or +0.254 mm):
   (2) If the EGT increases:
Subtask 49-00-81-810-169-A ** ON A/C NOT FOR ALL
C. If the WB parameter values are out of range:
  • do a check for blockage of the APU inlet.
   (1) If the fault continues:
     (a) If the inspection of the APU BLEED CHECK-VALVE (7260HM) is not OK:
     (b) If the inspection of the APU BLEED CHECK-VALVE (7260HM) is OK:
  • do a check for damage/contamination of the DIFFERENTIAL PRESSURE TRANSDUCER (P24) and TOTAL PRESSURE TRANSDUCER (P23)
  • remove both ends of the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (P24) AMM 49-51-16-000-004.
  • remove both ends of the tube of the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-000-004.
  • put plugs in the openings.
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.
  • use a air source to remove unwanted materials out of the tubes.
  • remove the plugs from the openings.
  • install the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (P24) AMM 49-51-16-400-003.
  • install the tube of the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-400-003.
     (c) If the fault continues:
     (d) If the fault continues:
  • do a check of damage/leakage of the fuel supply and return lines of the SCV
       1 If there is damaged/leaking in the fuel supply and return lines:
  • do a repair.
       2 If the fuel supply and return lines are OK:
     (e) If the fault continues:
Subtask 49-00-81-810-170-A ** ON A/C NOT FOR ALL
D. If the PD is more than 8 psig lower than PT (ECS or MES mode):
NOTE: PD = main engine precooler inlet air pressure (source BMC).
NOTE: As a rule of thumb, the pressure drop accross the cross bleed valve is 3 psig, therefore PD (RTL mode) shows approx. 3 psig higher than PD (ECS or MES mode).
NOTE: The following check is only applicable to ECS and MES modes.
  • check on the MCDU the load control valve position.
   (1) If the ADW1 shows that the load control valve is not open (e.g. ADW1 = 08518 in MES mode, ADW1 = 00118 in ECS mode):
   (2) If the ADW1 shows that load control valve is fully open (e.g. ADW1 = 08519 in MES mode, ADW1 = 00119 in ECS mode):
  • in the APU compartment, do a check of the load control valve position.
     (a) If the load control valve is fully open:
       1 If the fault continues:
Subtask 49-00-81-810-171-A ** ON A/C NOT FOR ALL
E. If the LCIT is more than 10 deg.C higher than the outside air temperature (TAT):
  • check for hot gas ingestion (make sure that the main engine exhaust is not blown into the APU air intake),
  • check for hot gas leaks at the APU compressor split lines.
   (1) If the fault appears to be intermitted:
     (a) If the fault continues:
Subtask 49-00-81-810-174-A ** ON A/C NOT FOR ALL
F. If the LCIT is more than 10 deg.C lower than the outside air temperature (TAT):
   (1) If the fault continues:
     (a) If the fault continues:
  • do a check and repair of the aircraft wiring from the ECB (59KD) AB/H4,H3 to the INLET TEMP SENSOR studs/alumel,chromel ASM 496202 ASM 496204.
Subtask 49-00-81-810-156-B ** ON A/C NOT FOR ALL
G. If the self test gives the maintenance message:

Subtask 49-00-81-810-168-B ** ON A/C NOT FOR ALL
H. If the IGV parameter values are out of range:
  • check that the EGT increase during a mode change (i.e. RTL to ECS).
NOTE: RTL = Ready To Load
   (1) If the EGT does not increase:
  • remove the IGV ACTUATOR 8014KM AMM 49-23-51-000-004.
  • do a push/pull test on the IGVs to check the IGV movement.
    .make sure that the IGV has a travel range of 1 -0.01 in. or +0.01 in. (25.400 -0.254 mm or +0.254 mm).
    .measure the force of the IGV movement.
     (a) If a force less than 20 lbf (8.8964 daN) is necessary to move the IGVs:
     (b) If a force more than 20 lbf (8.8964 daN) is necessary to move the IGVs or the travel range is different than 1 -0.01 in. or +0.01 in. (25.400 -0.254 mm or +0.254 mm):
   (2) If the EGT increases:
Subtask 49-00-81-810-169-B ** ON A/C NOT FOR ALL
I. If the WB parameter values are out of range:
  • do a check for blockage of the APU inlet.
   (1) If the fault continues:
     (a) If the inspection of the APU BLEED CHECK-VALVE (7260HM) is not OK:
     (b) If the inspection 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 both ends of the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM) AMM 49-51-16-000-004.
  • remove both ends of the tube of the TOTAL PRESSURE TRANSDUCER (8044KM) AMM 49-51-17-000-004.
  • put plugs in the openings.
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.
  • use a air source to remove unwanted materials out of the tubes.
  • remove the plugs from the openings.
  • install the tube of the DIFFERENTIAL PRESSURE TRANSDUCER (8043KM) AMM 49-51-16-400-003.
  • install the tube of the TOTAL PRESSURE TRANSDUCER (8044KM) AMM 49-51-17-400-003.
     (c) If the fault continues:
     (d) If the fault continues:
  • do a check of damage/leakage of the fuel supply and return lines of the SCV
       1 If there is damaged/leaking in the fuel supply and return lines:
  • do a repair.
       2 If the fuel supply and return lines are OK:
     (e) If the fault continues:
Subtask 49-00-81-810-170-B ** ON A/C NOT FOR ALL
J. If the PD is more than 8 psig lower than PT (ECS or MES mode):
NOTE: PD = main engine precooler inlet air pressure (source BMC).
NOTE: As a rule of thumb, the pressure drop accross the cross bleed valve is 3 psig, therefore PD (RTL mode) shows approx. 3 psig higher than PD (ECS or MES mode).
  • check on the MCDU the load control valve position (the ADW1 parameter shows a 9 in the last position i.e. 08519 = load control valve open).
  • AMM 49-00-00-720-002.
   (1) If the ADW1 shows that the load control valve is not open (e.g. ADW1 = 08108):
   (2) If the ADW1 shows that load control valve is fully open (e.g. ADW1 = 0811A):
  • in the APU compartment, do a check of the load control valve position.
     (a) If the load control valve is fully open:
       1 If the fault continues:
Subtask 49-00-81-810-171-B ** ON A/C NOT FOR ALL
K. If the LCIT is more than 10 deg.C higher than the outside air temperature (TAT):
  • check for hot gas ingestion (make sure that the main engine exhaust is not blown into the APU air intake),
  • check for hot gas leaks at the APU compressor split lines.
   (1) If the fault appears to be intermitted:
  • do a check and repair of the aircraft wiring
    from the ECB (59KD) AB/H3,H4 to the electrical connector P1/7,6
    and
    from P1/7,6 to the Inlet Temp Sensor P6/B,A
    ASM 496104
  • replace the INLET TEMP SENSOR (8010KM) AMM 49-23-14-000-001 and AMM 49-23-14-400-001.
     (a) If the fault continues:
Subtask 49-00-81-810-174-B ** ON A/C NOT FOR ALL
L. If the LCIT is more than 10 deg.C lower than the outside air temperature (TAT):
  • do a check and repair of the aircraft wiring
    from the ECB (59KD) AB/H3,H4 to the electrical connector P1/7,6
    and
    from P1/7,6 to the Inlet Temp Sensor P6/B,A
    ASM 496104
  • replace the INLET TEMP SENSOR (8010KM) AMM 49-23-14-000-001 and AMM 49-23-14-400-001.
   (1) If the fault continues:
     (a) If the fault continues:
  • do a check and repair of the aircraft wiring from the ECB (59KD) AB/H4,H3 to the INLET TEMP SENSOR studs/alumel,chromel ASM 496202 ASM 496204.
Subtask 49-00-81-810-172-A ** ON A/C NOT FOR ALL
M. If the bleed pressure is low to start one engine with the other in MIN IDLE operation and the APU self test gives no maintenance message:
  • isolate the left or right engine.
NOTE: On the APU page of the lower ECAM display unit, the BLEED (PSI) value is within 8 psig.
NOTE: Aircraft configuration:
  • the PACK 1 and 2 p/bsw are OFF,
  • the APU BLEED valve p/bsw is ON,
  • do one MES at a time.
   (1) For the related engine:
  • do the trouble shooting of the engine STARTER SHUTOFF VALVE (SAV).
     (a) If the fault continues:
       1 If the test gives a maintenance message:
  • do the related trouble shooting procedure.
       2 If the test is OK:
  • do a leak check of the aircraft bleed system .
Subtask 49-00-81-810-173-A ** ON A/C NOT FOR ALL
N. If:
.the bleed pressure has large fluctuation of +/- 20 psig with both packs in operation.
.the APU self test gives no maintenance message.
NOTE: If one pack is operating, the external temperature and the cabin temperature are high, APU bleed-pressure fluctuation occurs when you start the second pack to decrease the cabin temperature.
This bleed pressure fluctuation is a normal effect after the start of the two pack operation in maximum cooling mode until the cabin temperature has decreased sufficiently after some time.
   (1) If the fault continues:
Subtask 49-00-81-810-173-B ** ON A/C NOT FOR ALL
N. If:
.The bleed pressure has large fluctuation of plus or minus 20 psig when the two packs are in operation.
.The APU self-test gives no maintenance message.
NOTE: If one pack is in operation and the external and the cabin temperatures are high, the APU bleed-pressure fluctuation occurs when you start the second pack to decrease the cabin temperature.
This bleed pressure fluctuation is normal after the start of the two packs in the maximum cooling mode. The bleed pressure stays constant when the cabin temperature decreases sufficiently after some time.
   (1) If the fault continues:
Subtask 49-00-81-710-233-A ** ON A/C NOT FOR ALL
O. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:34:38 UTC
"WTRUIB" 2025