DOC AIRBUS | AMM A320FFan Trim Balance - 1 Sensor 1 Speed [CFMI]
TASK 71-00-00-750-001-A-01
Fan Trim Balance - 1 Sensor 1 Speed
1. Reason for the Job
This procedure is to use only when the computing equipment necessary to do a "1 sensor, 3 speeds" ground balancing procedure is not available, because it is not as reliable as the "1 sensor, 3 speeds" procedure, but permits to clear the aircraft for a flight.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Job Set-up
Subtask 71-00-00-869-207-A ** ON A/C NOT FOR ALL
Subtask 71-00-00-710-067-B ** ON A/C NOT FOR ALL Subtask 71-00-00-869-077-B ** ON A/C NOT FOR ALL
Subtask 71-00-00-869-079-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 02:21:36 UTC
Fan Trim Balance - 1 Sensor 1 Speed
1. Reason for the Job
This procedure is to use only when the computing equipment necessary to do a "1 sensor, 3 speeds" ground balancing procedure is not available, because it is not as reliable as the "1 sensor, 3 speeds" procedure, but permits to clear the aircraft for a flight.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| 98F10103500000 | 2 | CHOCK-MLG,ENGINE RUN-UP |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 31-32-00-860-012-A | Procedure to Get Access to the SYSTEM REPORT/TEST/ENG Page |
| TASK 71-00-00-710-003-A | Engine Automatic Start |
| TASK 71-00-00-869-005-A | Wind Limitations During Engine Ground Operations |
| TASK 71-00-00-869-006-A | Safety Precautions During Engine Ground Operations |
| TASK 77-32-34-869-042-A | Acquire Unbalance Data During the Flight and Read Unbalance Data |
Tool InstallationSubtask 71-00-00-869-207-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(2) Make sure that the 98F10103500000 CHOCK-MLG,ENGINE RUN-UP are in position in front of each forward outboard MLG wheel.
(3) Make sure that there is a minimum 6014 lb (2728 kg) of fuel in the inner tanks to make sure that the aircraft is stable during the test.
(5) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to the idle position.
Subtask 71-00-00-865-099-A ** ON A/C NOT FOR ALL CAUTION:
MAKE SURE THAT THE AIRCRAFT IS PARKED ON A CLEAN, DRY AND FLAT SURFACE. THERE MUST BE NO OIL, GREASE OR SIMILAR MATERIALS ON THE SURFACE.
THE PAVEMENT MUST NOT BE BROKEN OR LOOSE, AND WE RECOMMEND CONCRETE MATERIAL BECAUSE ASPHALT CAN MELT AND CAUSE DAMAGE TO THE AIRCRAFT.
(1) Obey the wind limitations and safety precautions during engine ground operation (Ref. AMM TASK 71-00-00-869-005) and (Ref. AMM TASK 71-00-00-869-006). (2) Make sure that the 98F10103500000 CHOCK-MLG,ENGINE RUN-UP are in position in front of each forward outboard MLG wheel.
(3) Make sure that there is a minimum 6014 lb (2728 kg) of fuel in the inner tanks to make sure that the aircraft is stable during the test.
NOTE: This minimum fuel quantity does not include the fuel consumption of the engines necessary to do the test. This minimum quantity must stay in the inner tank at the end of the test.
(4) There must be two qualified persons in the cockpit when performing an engine run. One must monitor the outside and the aircraft behavior while the other performs the engine test. (5) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to the idle position.
B. Make sure that this(these) circuit breaker(s) is(are) closed:
4. Procedure| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | L/G/LGCIU/SYS1/NORM | 1GA | C09 |
| 121VU | HYDRAULIC/LGCIU/SYS2 | 2GA | Q35 |
| 121VU | HYDRAULIC/LGCIU/SYS1/GRND SPLY | 52GA | Q34 |
Subtask 71-00-00-710-067-B ** ON A/C NOT FOR ALL Subtask 71-00-00-869-077-B ** ON A/C NOT FOR ALL
B. Aircraft Maintenance Configuration
(1) On the MCDU 1(2), get the SYSTEM REPORT/TEST ENG page (Ref. AMM TASK 31-32-00-860-012).
(2) Push the key adjacent to the EVMU indication: the first EVMU page comes into view.
(3) Push the NEXT PAGE key.
(4) Push the key adjacent to the ENGINE UNBALANCE indication.
(5) The EVMU ENGINE UNBALANCE menu comes into view.
Subtask 71-00-00-750-051-B ** ON A/C NOT FOR ALL (1) On the MCDU 1(2), get the SYSTEM REPORT/TEST ENG page (Ref. AMM TASK 31-32-00-860-012).
(2) Push the key adjacent to the EVMU indication: the first EVMU page comes into view.
(3) Push the NEXT PAGE key.
(4) Push the key adjacent to the ENGINE UNBALANCE indication.
(5) The EVMU ENGINE UNBALANCE menu comes into view.
C. Do this procedure:
1 Make sure that the A/SKID & N/WSTRG selector switch 5GG is ON.
2 Make sure that the PARKING BRAKE control switch is in ON position.
(b) Push and hold the brake pedals at the full limit position.
(c) On the RUD TRIM/PARKING BRK panel 110VU:
- Set the PARKING BRAKE control switch to OFF.
(2) Slowly increase power of the non tested engine to 60 percent N1.
(3) Slowly increase power to 80 percent N1 while monitoring the vibration parameters of the No. 1 bearing and TRF sensors.
(4) Warm up the engine at 80 percent N1 for 5 minutes.
(5) Increase engine rate to T/O N1 if the vibration amplitudes are less than 6.0 mils.
(7) Reduce power to minimum idle, let the engine power become stable for 5 minutes then stop the engines.
(8) Put the aircraft in the "parking-brake applied" configuration:
(a) On the RUD TRIM/PARKING BRK panel 110VU:
- Set the parking brake control switch to ON.
(b) Release the brake pedals.
(9) Calculate what follows:
(a) Multiply the amplitude of the vibration by 150 g.cm/mils.
Example: 2.1 x 150 = 315 g.cm.
(b) Determine the correction angle by subtracting the vibration angle from 200 degrees.
Example: 200 - 250 = - 50 = 310 degrees.
(10) Add the screw(s) best fitting the weight to be installed.
Example: 315 g.cm at 310 degrees corresponds to a PO4 screw in position No. 6.
(11) If a screw is already installed in this position, install a screw whose weight is nearest to the sum of the two screws.
(12) Install the determined screw(s) in the required position(s).
(13) Before N1 is more than or equal to 75 percent, do this procedure:
(c) On the RUD TRIM/PARKING BRK panel 110VU:
- Set the PARKING BRAKE control switch to OFF.
(14) Start the two engines and let them become stable at minimum idle for 5 minutes (Ref. AMM TASK 71-00-00-710-003)
(15) Slowly increase power of the non tested engine to 60 percent N1.
(16) Increase power of the tested engine to 80 percent N1, let the engine become stable for 5 minutes for engine warm up.
(17) Accelerate the engine to T/O N1 and make sure that the vibrations are in the limits before the flight.
(18) Reduce power to minimum idle, let the engine power become stable for 5 minutes then stop the engines.
(19) Put the aircraft in the "parking brake applied" configuration:
(a) On the panel 110VU:
(20) Program the EVMU to acquire unbalance data during the next flight (Ref. AMM TASK 77-32-34-869-042). Program these speeds: 62, 84, 94, 95 and 96 percent of N1 to permit a cold trim balance procedure after landing.
5. Close-upWARNING:
DO NOT LET ONE ENGINE OPERATE AT N1 GREATER THAN OR EQUAL TO 75 PERCENT WHEN ONLY THE WHEEL CHOCKS AND THE PARKING BRAKE STOP THE MOVEMENT OF THE AIRCRAFT.
(1) Before N1 is more than or equal to 75 percent, do this procedure: CAUTION:
DO NOT OPEN LGCIU CIRCUIT BREAKERS 1GA, 2GA AND 52GA. IF YOU DO THIS, AIRCRAFT BRAKING THROUGH BRAKE PEDALS DOES NOT OPERATE.
(a) On the landing gear control and indicating panel 402VU: 1 Make sure that the A/SKID & N/WSTRG selector switch 5GG is ON.
2 Make sure that the PARKING BRAKE control switch is in ON position.
(b) Push and hold the brake pedals at the full limit position.
(c) On the RUD TRIM/PARKING BRK panel 110VU:
- Set the PARKING BRAKE control switch to OFF.
(2) Slowly increase power of the non tested engine to 60 percent N1.
(3) Slowly increase power to 80 percent N1 while monitoring the vibration parameters of the No. 1 bearing and TRF sensors.
(4) Warm up the engine at 80 percent N1 for 5 minutes.
(5) Increase engine rate to T/O N1 if the vibration amplitudes are less than 6.0 mils.
NOTE: If the vibration amplitude is above 6 mils, do a fan trim balance on speed below 6 mils as a pre trim balance and then trim balance again until the vibration amplitude is below 6 mils.
(6) Record the amplitude (A) and angle (D) of the No. 1 bearing vibration at the maximum N1 reached. (7) Reduce power to minimum idle, let the engine power become stable for 5 minutes then stop the engines.
(8) Put the aircraft in the "parking-brake applied" configuration:
(a) On the RUD TRIM/PARKING BRK panel 110VU:
- Set the parking brake control switch to ON.
(b) Release the brake pedals.
(9) Calculate what follows:
(a) Multiply the amplitude of the vibration by 150 g.cm/mils.
Example: 2.1 x 150 = 315 g.cm.
(b) Determine the correction angle by subtracting the vibration angle from 200 degrees.
Example: 200 - 250 = - 50 = 310 degrees.
(10) Add the screw(s) best fitting the weight to be installed.
Example: 315 g.cm at 310 degrees corresponds to a PO4 screw in position No. 6.
(11) If a screw is already installed in this position, install a screw whose weight is nearest to the sum of the two screws.
| Example: One PO1 screw in position No. 6 = 84 g.cm |
| + One PO4 screw in position No. 6 = 314 g.cm |
| are equivalent to one PO5 screw in position No. 6 = 378 g.cm |
(12) Install the determined screw(s) in the required position(s).
(13) Before N1 is more than or equal to 75 percent, do this procedure:
CAUTION:
DO NOT OPEN LGCIU CIRCUIT BREAKERS 1GA, 2GA AND 52GA. IF YOU DO THIS, AIRCRAFT BRAKING THROUGH BRAKE PEDALS DOES NOT OPERATE.
(a) On the landing gear control and indicating panel 402VU: - Make sure that the A/SKID & N/WSTRG selector switch 5GG is ON.
- Make sure that the PARKING BRAKE control switch is in ON position.
(c) On the RUD TRIM/PARKING BRK panel 110VU:
- Set the PARKING BRAKE control switch to OFF.
(14) Start the two engines and let them become stable at minimum idle for 5 minutes (Ref. AMM TASK 71-00-00-710-003)
(15) Slowly increase power of the non tested engine to 60 percent N1.
(16) Increase power of the tested engine to 80 percent N1, let the engine become stable for 5 minutes for engine warm up.
(17) Accelerate the engine to T/O N1 and make sure that the vibrations are in the limits before the flight.
(18) Reduce power to minimum idle, let the engine power become stable for 5 minutes then stop the engines.
(19) Put the aircraft in the "parking brake applied" configuration:
(a) On the panel 110VU:
- Set the parking brake control switch to ON.
(20) Program the EVMU to acquire unbalance data during the next flight (Ref. AMM TASK 77-32-34-869-042). Program these speeds: 62, 84, 94, 95 and 96 percent of N1 to permit a cold trim balance procedure after landing.
Subtask 71-00-00-869-079-A ** ON A/C NOT FOR ALL
A. Make sure that the work area is clean and clear of tools and other items.