DOC AIRBUS | TSM A320FFailure of the 2.5 Bleed Actuator on the Engine 1, Channel A
1. Possible Causes
NOTE: This task is to troubleshoot the Clear Language Message (CLM) CHA 2.5 BLD ACT/HC/EEC1. The fault
acronyms listed in the fault confirmation section below will help you to focus on the correct cause of this
CLM.
· harness from the EEC connector (4000KS-J3) to the 2.5 bleed actuator (4021KS)
· ACTUATOR-MASTER, LPC BLEED ( 4021KS )
· EEC ( 4000KS )
· LPC bleed valve mechanism
· FMU ( 4000KC )
· PUMP-HP/LP FUEL ( 2001EM )
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
73-00-00-810-900-B Multiple Dual Track Check Faults on the Engine 1
75-30-00-810-863-A Failure of the LPC Bleed Master Actuator Channels A and B, on the
Engine 1 (A5 engines only)
Ref. AMM 24-41-00-861-002 Energize the Aircraft Electrical Circuits from the External Power
Ref. AMM 24-41-00-862-002 De-energize the Aircraft Electrical Circuits Supplied from the External
Power
Ref. AMM 31-60-00-860-002 EIS Stop Procedure
Ref. AMM 70-23-15-912-010 Connection of Electrical Connectors
Ref. AMM 71-00-00-710-013 Test No.11 : High Power Assurance Test
Ref. AMM 71-13-00-010-010 Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
Ref. AMM 71-13-00-410-010 Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
Ref. AMM 71-50-00-210-010 Wire Harness Visual Inspection - All Power Plant Electrical Cables
Ref. AMM 72-00-00-600-011 Lubrication of the LPC Bleed Valve Mechanism
Ref. AMM 72-00-00-720-010 Load Check of the LPC Bleed Valve Mechanism
Ref. AMM 72-32-60-200-011 Inspection of the LPC Bleed Duct Seal
Ref. AMM 73-12-41-000-010 Removal of the Low Pressure (LP)/High Pressure (HP) Fuel Pump
Ref. AMM 73-12-41-400-010 Installation of the Low Pressure (LP)/High Pressure (HP) Fuel Pump
Ref. AMM 73-22-00-710-040 Operational Test of the FADEC SYSTEM on the Ground
Ref. AMM 73-22-34-000-010 Removal of the Electronic Engine Control (EEC)
Ref. AMM 73-22-34-400-010 Installation of the Electronic Engine Control (EEC)
Ref. AMM 73-22-52-000-010 Removal of the Fuel Metering Unit (FMU)
Ref. AMM 73-22-52-400-010 Installation of the Fuel Metering Unit (FMU)
Ref. ASM 73-25-18
REFERENCE DESIGNATION
Ref. AMM 75-31-42-000-010 Removal of the Low Pressure Compressor (LPC) Bleed-Master Actuator
Ref. AMM 75-31-42-400-010 Installation of the Low Pressure Compressor (LPC) Bleed-Master Actuator
Ref. AMM 78-32-00-010-010 Opening of the Thrust Reverser Halves
Ref. AMM 78-32-00-410-010 Closing of the Thrust Reverser Halves
70-00-00-03-13 STANDARD PRACTICES - ENGINE - GENERAL - TASK SUPPORTING
DATA
Master LPC Bleed Actuator - Channel A SHEET 1
Failure of the 2.5 Bleed Actuator on the Engine 1, Channel A SHEET 1
Figure 75(IAE)-30-00-991-01300-A / SHEET 1/1 - Master LPC Bleed Actuator - Channel A not printed,
as per printing preferences
Figure 75(IAE)-30-00-991-01400-A / SHEET 1/1 - Failure of the 2.5 Bleed Actuator on the Engine 1,
Channel A not printed, as per printing preferences
3. Fault Confirmation
Subtask 75-30-00-860-114-A
A. Job Set-Up
NOTE: This task is to troubleshoot the Clear Language Message (CLM) CHA 2.5 BLD ACT/HC/EEC1 as
a single channel message or in combination with the Clear Language Message (CLM) 2.5 BLD
ACT/HC/EEC1. If you receive the Clear Language Message (CLM) CHB 2.5 BLD ACT/HC/EEC1
as well, follow the procedure for dual channel 2.5 actuator faults (Ref. TSM 75-30-00-810-863) .
NOTE: Multiple Dual Track Check Faults may indicate a failed fuel pump. Four control units on the engine
are driven by HP fuel: the VSV actuator, the 2.5 bleed actuators, the ACOC Air Modulating Valve
and the Active Clearance Control Actuator. If you have faults with two or more of these units, you
must follow the Multiple Dual Track Check Faults procedure (Ref. TSM 73-00-00-810-900) .
(1) Energize the aircraft electrical circuits
Ref. AMM 24-41-00-861-002 .
(2) On the panel 50VU, release the ENG FADEC GND PWR 1 and 2 pushbutton switches to the ON
position.
Subtask 75-30-00-710-166-A
B. Identify the Test for Fault Confirmation
NOTE: Troubleshooting can start immediately without doing the fault confirmation if this CLM was indicated
in multiple flight/ground legs.
(1) Do the CFDS message decoding and read the scheduled maintenance report to identify the fault
acronym related to the CLM message (Ref. TSM 70-00-00-03) .
(2) If the readout shows the fault acronym B25WAF or fault acronym B25L in FADEC 1A, do the
operational test of FADEC system on ground for fault confirmation Ref. AMM 73-22-00-710-040 .
(a) If the test shows the fault acronym B25WAF in FADEC 1A or there are two or more occurrences
in fault history, continue with fault isolation Para. 4.A.
(b) If the test shows the fault acronym B25L in FADEC 1A or there are two or more occurrences in
fault history, continue with fault isolation Para. 4.B.
(c) If the test does not show the fault acronym B25WAF or fault acronym B25L, send the engine
back to service.
(3) If the readout shows fault acronym B25TK in FADEC 1A, do the steps in Para. 3.C. for fault
confirmation.
(a) If the test shows the fault acronym B25TK or there are two or more occurrences in the fault
history, continue with fault isolation Para. 4.C.
(b) If the test does not show the fault acronym B25TK, send the engine back to service.
Subtask 75-30-00-710-251-A
C. Test for B25TK
(1) On the overhead panel 50VU, push the ENG FADEC GND PWR 1 to the OFF position and then
release it to the ON position.
NOTE: This step resets the FADEC memory.
(2) Do the test No 11 (high power assurance test) Ref. AMM 71-00-00-710-013 .
(3) Read the LAST LEG REPORT and the scheduled maintenance report of the FADEC 1A menu on the
MCDU (Ref. TSM 70-00-00-03) .
(a) Make a record of the failure message.
(b) Make a record of the channel FADEC 1A which found the fault.
(c) Do the CFDS message decoding and read the flight data and ground data to identify the fault
acronym.
4. Fault Isolation
(Ref. Fig. Master LPC Bleed Actuator - Channel A SHEET 1) (Ref. Fig. Failure of the 2.5 Bleed Actuator on the
Engine 1, Channel A SHEET 1)
Subtask 75-30-00-810-136-A
A. Fault Isolation for B25WAF
A torque motor wrap around fault (WAF) was found in channel A. The circuit for the 2.5 bleed actuator is
open, shorted to ground or has a wire to wire short.
NOTE: At all the time during this procedure, you can do the steps in Para. 3. to make sure the fault is corrected.
NOTE: Disconnection and connection of the electrical connectors, can correct this fault.
(1) Open the thrust reverser halves 451AL and 452AR Ref. AMM 78-32-00-010-010 .
(2) Open the fan cowls 437AL and 438AR Ref. AMM 71-13-00-010-010 .
(3) If the fault acronym was found in channel A, do the steps that follow:
(a) Visually examine the harness from the EEC connector (4000KS-J3) to the 2.5 bleed actuator
(4021KS) Ref. AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wiring chafing.
4 If a problem is found with the harness, repair or replace as necessary.
(b) If no problems are found with the harness, disconnect electrical connector (4021KS-B) from the
2.5 bleed actuator (4021KS) Ref. AMM 71-50-00-210-010 .
1 Examine pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for ovalized sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel small friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel A torque motor circuit in the 2.5 bleed actuator (4021KS)
Ref. ASM 73-25-18.
1 Make sure that contacts A and B are not shorted to ground.
2 Make sure that contacts A and B are not shorted to other contacts in the connector.
3 Make sure the resistance from contact A to contact B is between 25 and 41 ohms.
4 If a problem was found, remove and replace the ACTUATOR-MASTER, LPC
BLEED ( 4021KS ) Ref. AMM 75-31-42-000-010 and Ref. AMM 75-31-42-400-010 .
(d) If no problems were found, disconnect electrical connector (4000KS-J3) from the EEC (4000KS)
Ref. AMM 71-50-00-210-010 .
1 Examine pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for ovalized sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel small friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the torque motor wiring in the channel A harness.
1 Look for wire to wire shorts.
2 Look for shorts to ground.
3 Look for continuity (less than 5 Ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100000 (100K) ohms.
NOTE: A mis-wired harness can cause this problem. When testing these circuits, make sure
that the contacts are installed in the correct positions in each connector as specified
in the wiring diagram.
2.5 Bleed Actuator Torque Motor Circuit Channel A Harness
2.5 Bleed Actuator (4021KS) EEC (4000KS)
4021KS-B 4000KS-J3
Contacts Contacts
A F
B b
4 If a problem is found with the harness, repair or replace as necessary Ref. ASM 73-25-18.
(f) Install all removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3. for fault confirmation.
1 If the test does not show the fault acronym B25WAF, send the engine back to service.
2 If the test shows the fault acronym B25WAF, remove and replace the ACTUATORMASTER,
LPC BLEED ( 4021KS ) Ref. AMM 75-31-42-000-010 and Ref.
AMM 75-31-42-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
Subtask 75-30-00-810-116-A
B. Fault Isolation for B25L
· The 2.5 bleed actuator LVDT signal is out of range on engine 1. This is caused by an open, shorted to
ground or a wire to wire short in this circuit.
NOTE: At all the time during this procedure, you can do the steps in Para. 3. to make sure the fault is corrected.
NOTE: Disconnection and connection of the electrical connectors, can correct this fault.
(1) Open the thrust reverser halves 451AL and 452AR Ref. AMM 78-32-00-010-010 .
(2) If the fault acronym was found in channel A, do the steps that follow:
(a) Visually examine the harness from the EEC connector (4000KS-J4) to the 2.5 bleed actuator
(4021KS) Ref. AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wiring chafing.
4 If a problem is found with the harness, repair or replace as necessary.
(b) If no problems are found with the harness, disconnect electrical connector (4021KS-A) from the
2.5 bleed actuator (4021KS) Ref. AMM 71-50-00-210-010 .
1 Examine pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for ovalized sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel small friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel A LVDT circuit in the 2.5 bleed actuator (4021KS) Ref.
ASM 73-25-18.
1 Make sure that contacts A, B, C and D are not shorted to ground.
2 Make sure that contacts A, B, C and D are not shorted to other contacts in the connector.
3 Make sure the resistance from contact A to contact B is between 560 and 880 ohms.
4 Make sure the resistance from contact C to contact D is between 240 and 440 ohms.
5 If a problem was found, remove and replace the ACTUATOR-MASTER, LPC
BLEED ( 4021KS ) Ref. AMM 75-31-42-000-010 and Ref. AMM 75-31-42-400-010 .
(d) If no problems were found, disconnect electrical connector (4000KS-J4) from the EEC (4000KS)
Ref. AMM 71-50-00-210-010 .
1 Examine pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for ovalized sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel small friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the LVDT wiring in the channel A harness.
1 Look for wire to wire shorts.
2 Look for shorts to ground.
3 Look for continuity (less than 5 Ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100000 (100K) ohms.
NOTE: A mis-wired harness can cause this problem. When testing these circuits, make sure
that the contacts are installed in the correct positions in each connector as specified
in the wiring diagram.
2.5 Bleed Actuator LVDT Circuit Channel A Harness
2.5 Bleed Actuator (4021KS) EEC (4000KS)
4021KS-A 4000KS-J4
Contacts Contacts
A q
B r
C M
D e
4 If a problem is found with the harness, repair or replace as necessary Ref. ASM 73-25-18.
(f) Install all removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3. for fault confirmation.
1 If the test does not show the fault acronym B25L, send the engine back to service.
2 If the test shows the fault acronym B25L, remove and replace the ACTUATOR-MASTER,
LPC BLEED ( 4021KS ) Ref. AMM 75-31-42-000-010 and Ref. AMM 75-31-42-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
Subtask 75-30-00-810-153-A
C. Fault Isolation for B25TK
A Track-check fault was found in channel A. The 2.5 bleed actuator cannot move to its commanded
position or it is moving slower than normal.
NOTE: At all the time during this procedure, you can do the steps in Para. 3. to make sure the fault is corrected.
NOTE: This fault is typically caused by a mechanical problem and not an electrical problem.
(1) Open the thrust reverser halves 451AL and 452AR Ref. AMM 78-32-00-010-010 .
(2) Examine the LPC bleed valve mechanism Ref. AMM 72-00-00-720-010 .
(3) Do an inspection of the LPT bleed duct for a detached seal Ref. AMM 72-32-60-200-011 .
(4) Do a lubrication of the LPC bleed valve mechanism Ref. AMM 72-00-00-600-011 .
(5) Do the test listed in Para. 3. for fault confirmation.
(6) If the test was satisfactory, send the engine back to service.
(7) If the test was not satisfactory, remove and replace the ACTUATOR-MASTER, LPC
BLEED ( 4021KS ) Ref. AMM 75-31-42-000-010 and Ref. AMM 75-31-42-400-010 .
(a) If the fault continues, remove and replace the EEC ( 4000KS ) , Ref. AMM 73-22-34-000-010
and Ref. AMM 73-22-34-400-010 .
(b) If the fault continues, remove and replace the FMU ( 4000KC ) , Ref. AMM 73-22-52-000-010
and Ref. AMM 73-22-52-400-010 .
(c) If the fault continues, remove and replace the PUMP-HP/LP FUEL ( 2001EM ) , Ref.
AMM 73-12-41-000-010 and Ref. AMM 73-12-41-400-010 .
(8) If the fault continues, do the steps that follow:
(a) Do the steps for B25WAF listed in Para. 4.A. above.
(b) Do the steps for B25L listed in Para. 4.B. above.
5. Close-up
Subtask 75-30-00-860-115-A
A. Put the aircraft back to its initial configuration.
(1) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
Ref. AMM 31-60-00-860-002 .
(2) On the panel 50VU, push the ENG/FADEC GND PWR/1 pushbutton switch to the OFF position.
(3) De-energize the aircraft electrical circuits
Ref. AMM 24-41-00-862-002 .
(4) Make sure that the thrust reverser halves 451AL and 452AR are closed Ref.
AMM 78-32-00-410-010 .
(5) Make sure that the fan cowls 437AL and 438AR are closed Ref. AMM 71-13-00-410-010 . [Rev.6 from Feb 2017] 2026.04.04 04:37:16 UTC