DOC AIRBUS | TSM A320FHalf Speed Operation Detected
TASK 27-51-00-810-826-A
Half Speed Operation Detected
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 27-51-00-865-069-A
Subtask 27-51-00-810-075-A
Subtask 27-51-00-942-074-A
[Rev.8 from Aug 2018]
2026.04.04 04:27:39 UTC
Half Speed Operation Detected
1. Possible Causes
- VALVE BLOCK-FLAP 1 [23CV]
- VALVE BLOCK-FLAP 2 [24CV]
- aircraft wiring
- POB Solenoid Valve
- Hydraulic Motor of the Flap Power Control Unit
- FILTERS
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | MEGOHMMETER 100 MOHMS - MEASURING VOLTAGE 45 VDC |
| No specific | 1 | MULTIMETER - STANDARD |
| REFERENCE | DESIGNATION |
|---|---|
| ASM 275102 | |
| ASM 275103 | |
| AMM 27-54-00-710-001 | Operational Test of the Flap System |
| AMM 27-54-52-000-001 | Removal of the Pressure-Off Brake of the Flap Power Control Unit |
| AMM 27-54-52-400-001 | Installation of the Pressure-Off Brake of the Flap Power Control Unit |
| AMM 27-54-53-000-001 | Removal of the Valve Blocks of the Power Control Unit (Flap) |
| AMM 27-54-53-000-002 | Removal of the Solenoid Valves of the Power Control Unit (Flap) |
| AMM 27-54-53-000-003 | Removal of the Filters of the Valve Blocks |
| AMM 27-54-53-400-001 | Installation of the Valve Blocks of the Power Control Unit (Flap) |
| AMM 27-54-53-400-002 | Installation of the Solenoid Valves of the Power Control Unit (Flap) |
| AMM 27-54-53-400-003 | Installation of the Filters of the Valve Blocks |
| AMM 27-54-54-000-002 | Removal of the Hydraulic Motor of the Flap Power Control-Unit without the Pressure-Off Brake and the Valve Block Assembly |
| AMM 27-54-54-400-002 | Installation of the Hydraulic Motor of the Flap Power Control-Unit without the Pressure-Off Brake and the Valve Block Assembly |
Subtask 27-51-00-865-069-A
A. Table of the circuit breakers used in this procedure:
Subtask 27-51-00-710-062-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 49VU | FLIGHT CONTROLS/FLP/CTL AND MONG/SYS1 | 6CV | B07 |
| 121VU | FLIGHT CONTROLS/FLP/CTL AND/MONG/SYS2 | 8CV | Q21 |
B. SFCC Reset and Initialization.
(1) At the circuit breakers.
(a) Open the circuit breakers.
(b) Wait for 3 seconds and close the circuit breakers.
(c) Wait for 60 seconds.
(d) Check the UPPER ECAM and the SD FLT/CTL page for the fault warnings.
(e) If the ECAM warning message clears, set the MCDU to MENU MODE and access the FLP ON GROUND FAULTS page and make sure that the ground log is clear.
(f) If the ECAM warning and the fault message stay displayed, do the fault isolation.
4. Fault Isolation(1) At the circuit breakers.
(a) Open the circuit breakers.
(b) Wait for 3 seconds and close the circuit breakers.
(c) Wait for 60 seconds.
(d) Check the UPPER ECAM and the SD FLT/CTL page for the fault warnings.
(e) If the ECAM warning message clears, set the MCDU to MENU MODE and access the FLP ON GROUND FAULTS page and make sure that the ground log is clear.
(f) If the ECAM warning and the fault message stay displayed, do the fault isolation.
Subtask 27-51-00-810-075-A
A. Procedure
(1) Do the operational test of the flap system AMM 27-54-00-710-001
(3) If the fault indication gives a slow extension or a slow retraction without a hydraulic fault, isolate the PCU and compare the two motor speeds:
(a) Stop the SFCC 1 and move the flaps. Measure the extension time.
(b) Energize the SFCC 1 and stop the SFCC 2.
(c) Move the flaps and measure the extension time.
(4) Do a check of the POB electrical circuit:
(a) Refer to AMM 27-54-52-000-001 Figure 401/Task 27-54-52-991-001.
(b) Find the electrical connector for the VALVE BLOCK-FLAP 1 [23CV] or VALVE BLOCK-FLAP 2 [24CV] POB solenoids and release it.
(c) Do a check of the aircraft wiring from the SFCC ARINC tray interface to the POB solenoid electrical connectors 23CV-A/24CV-A ASM 275102 and ASM 275103.
(d) If there is a wiring/interface fault, do the repair.
(5) If the A/C wiring is satisfactory, do a check of the circuit resistance and isolate the circuit of the fault related solenoid valve.
(a) On the valve-block use a MULTIMETER - STANDARD and do a check of the resistance between:
(a) For the POB solenoid, connect the pins L & K together.
(b) Connect one test lead of the MEGOHMMETER 100 MOHMS - MEASURING VOLTAGE 45 VDC or a 50VDC +5VDC/-5VDC Isolation Tester to the pins LK and the other test lead to pin G.
(c) Supply a test signal for 5 seconds and read the shown resistance value.
(d) The resistance value must be more than 100 Megohms.
(7) If the results of one of the two POB Solenoid Valve tests in Paras 4.A.(5) and (6) are unsatisfactory, replace the POB solenoid valve,
AMM 27-54-53-000-002 and AMM 27-54-53-400-002.
(8) If the results of one of the two POB Solenoid Valve tests in Paras 4.A.(5) and (6) are satisfactory, replace the POB related to the defective channel,
AMM 27-54-52-000-001 and AMM 27-54-52-400-001.
(9) Do the test in Para 4.A.(3) and if the flaps do not move freely, replace the Hydraulic Motor of the Flap Power Control Unit ,
AMM 27-54-54-000-002 and AMM 27-54-54-400-002.
(10) If the test in Para 4.A.(3) is satisfactory, do the test given in Para 4.A.(1).
(11) Set the MCDU to MENU MODE and get access to the FLP ON GROUND FAULTS page and make sure that the ground log is clear.
(12) If the CFDS shows the same fault message, then the fault is with the PCU valve-block.
(a) Examine the valve-block FILTERS AMM 27-54-53-000-003 and AMM 27-54-53-400-003 and clean/replace the examined item.
(b) If the fault continues, do the test in Para 4.A.(1) and do a check of the FLP ON GROUND FAULTS page.
(c) Examine the VALVE BLOCK-FLAP 1 [23CV] or VALVE BLOCK-FLAP 2 [24CV] and replace the defective item,
AMM 27-54-53-000-001 and AMM 27-54-53-400-001.
(d) Do the test in Para 4.A.(1) and make sure that the ground log is clear.
(e) Do the SFCC 1 (2) reset (refer to Para 3.B.).
5. Close-up(1) Do the operational test of the flap system AMM 27-54-00-710-001
NOTE: For this operational test, it is necessary that the Power Transfer Unit (PTU) is in operation.
(2) During the test procedure, monitor the ECAM display for the fault indications. (3) If the fault indication gives a slow extension or a slow retraction without a hydraulic fault, isolate the PCU and compare the two motor speeds:
(a) Stop the SFCC 1 and move the flaps. Measure the extension time.
(b) Energize the SFCC 1 and stop the SFCC 2.
(c) Move the flaps and measure the extension time.
NOTE: The time difference shows the slowest system. The slowest system is the PCU with possible internal friction.
(d) During the steps above, if one SFCC is energized and a flap extension starts but the flaps do not move freely: - Do a check of the POB solenoid circuit (refer to Para 4.A.(4)).
(4) Do a check of the POB electrical circuit:
(a) Refer to AMM 27-54-52-000-001 Figure 401/Task 27-54-52-991-001.
(b) Find the electrical connector for the VALVE BLOCK-FLAP 1 [23CV] or VALVE BLOCK-FLAP 2 [24CV] POB solenoids and release it.
(c) Do a check of the aircraft wiring from the SFCC ARINC tray interface to the POB solenoid electrical connectors 23CV-A/24CV-A ASM 275102 and ASM 275103.
(d) If there is a wiring/interface fault, do the repair.
(5) If the A/C wiring is satisfactory, do a check of the circuit resistance and isolate the circuit of the fault related solenoid valve.
(a) On the valve-block use a MULTIMETER - STANDARD and do a check of the resistance between:
| For SFCC1 -23CV = POB pins L and K |
| SM/275102S01 |
| For SFCC2 -24CV = POB pins L and K |
| SM/275103S01 |
- The resistance for the POB solenoid valve 667C0000-02 must be between 71 ohms and 84 ohms.
- The resistance for the POB solenoid valve 903A0000-01 must be between 53 ohms and 60 ohms.
- The resistance for the POB solenoid valve 5751A0000-01 must be between 53 ohms and 60 ohms.
(a) For the POB solenoid, connect the pins L & K together.
(b) Connect one test lead of the MEGOHMMETER 100 MOHMS - MEASURING VOLTAGE 45 VDC or a 50VDC +5VDC/-5VDC Isolation Tester to the pins LK and the other test lead to pin G.
(c) Supply a test signal for 5 seconds and read the shown resistance value.
(d) The resistance value must be more than 100 Megohms.
(7) If the results of one of the two POB Solenoid Valve tests in Paras 4.A.(5) and (6) are unsatisfactory, replace the POB solenoid valve,
AMM 27-54-53-000-002 and AMM 27-54-53-400-002.
(8) If the results of one of the two POB Solenoid Valve tests in Paras 4.A.(5) and (6) are satisfactory, replace the POB related to the defective channel,
AMM 27-54-52-000-001 and AMM 27-54-52-400-001.
(9) Do the test in Para 4.A.(3) and if the flaps do not move freely, replace the Hydraulic Motor of the Flap Power Control Unit ,
AMM 27-54-54-000-002 and AMM 27-54-54-400-002.
(10) If the test in Para 4.A.(3) is satisfactory, do the test given in Para 4.A.(1).
(11) Set the MCDU to MENU MODE and get access to the FLP ON GROUND FAULTS page and make sure that the ground log is clear.
(12) If the CFDS shows the same fault message, then the fault is with the PCU valve-block.
(a) Examine the valve-block FILTERS AMM 27-54-53-000-003 and AMM 27-54-53-400-003 and clean/replace the examined item.
(b) If the fault continues, do the test in Para 4.A.(1) and do a check of the FLP ON GROUND FAULTS page.
(c) Examine the VALVE BLOCK-FLAP 1 [23CV] or VALVE BLOCK-FLAP 2 [24CV] and replace the defective item,
AMM 27-54-53-000-001 and AMM 27-54-53-400-001.
(d) Do the test in Para 4.A.(1) and make sure that the ground log is clear.
(e) Do the SFCC 1 (2) reset (refer to Para 3.B.).
Subtask 27-51-00-942-074-A
A. Remove the ground support and maintenance equipment, the special and standard tools and all other items.
Subtask 27-51-00-860-076-A B. Put the aircraft back to its initial configuration.