DOC AIRBUS | AMM A320FTest No.9A : LP Compressor (Fan) Trim Balancing - Trial Weight Method [IAE]
TASK 71-00-00-700-012-B-01
Test No.9A : LP Compressor (Fan) Trim Balancing - Trial Weight Method
A. This TASK gives an instruction of Test No.9 (Trial Weight Method).
B. Trim balance procedures for the LP compressor (fan) rotor have the two methods that follow:
(1) Test 9: This procedure uses vibration amplitude and unbalance phase angle indication which are identified by the Engine Vibration Monitoring Unit (EVMU), then the unbalance moment weight and the actual phase angle are calculated. For the calculation it is necessary to use influence coefficiences. It consists of these that follow:
(a) Mass coefficient: Relation of the vibration amplitude indication (mils) to unbalance moment weight (oz. in).
(b) Phase lag: Different angle between the actual phase angle and the EVMU phase angle indication.
(2) The detailled values at each speed are given in these procedures. Test 9 requires fewer engine runs than Test 9A.
(3) Test 9A: This procedure uses three trial trim balance weights (dummy weights). It makes you compare the actual unbalance vibration indication with the unbalance indication with the three trial trim balance weights installed at the consecutive positions (bolt holes).
The data is vectorially plotted to find the phase angle and the vibration amount necessary for the final trim balance. Test 9A is able to get more accurated balancing than Test 9.
C. As an alternative solution, you can use the Fan Trim Balance with the EVMU (refer to chapter 77-32-34 pb 501).
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Referenced Information
3. Job Set-up
Subtask 71-00-00-869-196-A ** ON A/C NOT FOR ALL
Subtask 71-00-00-750-079-A ** ON A/C NOT FOR ALL
When you measure vibration angle you must measure it in the counterclockwise direction looking from the engine front.
Trim balance weights must be installed at the same positions as the temporary marks made on the front blade retaining ring.
(1) Do Test No.8 (Ref. AMM TASK 71-00-00-700-022).
(2) Measure and record the following data.
(a) N1/N2 vibration peaks.
(b) N1/N2 speeds at which the vibration peaks occurs.
(3) Continue Test No.8 until you finish measuring the vibration at the vibration check points.
Subtask 71-00-00-750-080-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 02:28:21 UTC
Test No.9A : LP Compressor (Fan) Trim Balancing - Trial Weight Method
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
1. Reason for the JobA. This TASK gives an instruction of Test No.9 (Trial Weight Method).
B. Trim balance procedures for the LP compressor (fan) rotor have the two methods that follow:
(1) Test 9: This procedure uses vibration amplitude and unbalance phase angle indication which are identified by the Engine Vibration Monitoring Unit (EVMU), then the unbalance moment weight and the actual phase angle are calculated. For the calculation it is necessary to use influence coefficiences. It consists of these that follow:
(a) Mass coefficient: Relation of the vibration amplitude indication (mils) to unbalance moment weight (oz. in).
(b) Phase lag: Different angle between the actual phase angle and the EVMU phase angle indication.
(2) The detailled values at each speed are given in these procedures. Test 9 requires fewer engine runs than Test 9A.
(3) Test 9A: This procedure uses three trial trim balance weights (dummy weights). It makes you compare the actual unbalance vibration indication with the unbalance indication with the three trial trim balance weights installed at the consecutive positions (bolt holes).
The data is vectorially plotted to find the phase angle and the vibration amount necessary for the final trim balance. Test 9A is able to get more accurated balancing than Test 9.
C. As an alternative solution, you can use the Fan Trim Balance with the EVMU (refer to chapter 77-32-34 pb 501).
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | ACCESS PLATFORM 1M(3 FT) |
| No specific | AR | MAT - WORK |
| No specific | AR | WARNING NOTICE(S) |
| No specific | Torque wrench: range to between 220 and 180 lbf.in (2.49 and 2.03 m.daN )  | |
| 98F10103500000 | 2 | CHOCK-MLG,ENGINE RUN-UP |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.V06-069) | marker |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 70-23-11-911-013-A | General Torque Tightening Techniques |
| TASK 71-00-00-700-022-B | Test No.8 : Vibration Survey |
| TASK 71-00-00-710-018-A | Discontinued Start, Restart and Shutdown Procedures |
| TASK 71-00-00-860-010-B | Engine Operation Limits, Guidelines and Special Procedures |
| TASK 71-00-00-860-012-A | Engine Safety Precautions |
| TASK 72-38-11-000-010-A | Removal of the Inlet Cone |
| TASK 72-38-11-400-010-A | Installation of the Inlet Cone |
Tool InstallationSubtask 71-00-00-869-196-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(1) Make sure that the 98F10103500000 CHOCK-MLG,ENGINE RUN-UP are in position in front of each forward outboard MLG wheel.
(3) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to the idle position.
4. Procedure(1) Make sure that the 98F10103500000 CHOCK-MLG,ENGINE RUN-UP are in position in front of each forward outboard MLG wheel.
NOTE: For general information, refer to the engine safety precautions (Ref. AMM TASK 71-00-00-860-012) and engine operation limits, guidelines and special procedures (Ref. AMM TASK 71-00-00-860-010).
(2) 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. (3) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to the idle position.
Subtask 71-00-00-750-079-A ** ON A/C NOT FOR ALL
CAUTION:
DURING GROUND RUNNING, CONCERN FOR FAN BLADE INTEGRITY PROHIBITS STABILISED ENGINE OPERATION IN THE FOLLOWING SPEED RANGE:
- FOR PRE-SCN17/V A/C: DO NOT STABILISE THE ENGINE BETWEEN 61% TO 74% N1 SPEED RANGE
- FOR POST-SCN17/V A/C: STABILISED OPERATION OF THE ENGINE BETWEEN APPROXIMATELY 60% TO 74% N1 SPEED RANGE (LIMITS ARE A FUNCTION OF OUTSIDE TEMPERATURE) WILL BE PROHIBITED BY THE EEC, AS THE SOFTWARE INCLUDES THE KEEP-OUT-ZONE FOR ON-GROUND, STATIC OPERATION.
CAUTION:
OPERATE BOTH ENGINES FOR THIS TEST. POWER DIFFERENCE BETWEEN TWO ENGINES CAN MAKE THE AIRCRAFT UNSTABLE.
CAUTION:
DO NOT INCREASE ENGINE SPEED TO MORE THAN 85 PERCENT (4803 RPM) N1. EXCESSIVE ENGINE SPEED CAN CAUSE AIRCRAFT BUFFET.
A. Measure the Vibration Peaks NOTE: Test No.9A requires three trial trim balance weights (dummy weights). Use the actual trial trim balance weights, Fig. Item No.(14) identification No.5A0014, as the trial trim balance weights (dummy weights). Refer to Table 4.
NOTE: Test No.9A requires graphical vectorial analysis. Prepare and use a polar graph sheet.
NOTE: Speed (N1) is given as a percentage of the LP shaft turn speed. 100 percent = 5650 RPM.
NOTE: Trim phase angle (AK) is the angle from the top position (timing mark) to the unbalance position (lighter position).
NOTE: If the vibration exceeds the limits, slowly decrease the engine speed to idle, shutdown the engine and find the cause.
When you measure vibration amount and angle, you must use the same vibration channel throughout the TASK. When you measure vibration angle you must measure it in the counterclockwise direction looking from the engine front.
Trim balance weights must be installed at the same positions as the temporary marks made on the front blade retaining ring.
(1) Do Test No.8 (Ref. AMM TASK 71-00-00-700-022).
(2) Measure and record the following data.
(a) N1/N2 vibration peaks.
(b) N1/N2 speeds at which the vibration peaks occurs.
(3) Continue Test No.8 until you finish measuring the vibration at the vibration check points.
B. Measure the Vibration at the Vibration Check Points Instructed in Table 3.
(1) Slowly increase the engine speed to more than the maximum check point (83 percent N1) but not more than 85 percent N1.
(2) Slowly decrease the engine speed to the vibration check points which are shown in the Table 3.
(4) Measure the engine speeds (AS1, AS2, AS3), vibration amounts (AV1, AV2, AV3) and angles (AD1, AD2, AD3) in LP order at the three vibration check points and write on the Table 3.
(5) Go back to MIN IDLE for five minutes.
(6) Do a shutdown by the Discontinued Start, Restart and Shutdown Procedures (Ref. AMM TASK 71-00-00-710-018).
Subtask 71-00-00-750-081-A ** ON A/C NOT FOR ALL (1) Slowly increase the engine speed to more than the maximum check point (83 percent N1) but not more than 85 percent N1.
(2) Slowly decrease the engine speed to the vibration check points which are shown in the Table 3.
NOTE: When you measure the vibration you must take the measurement points going down in speed.
(3) After the engine speed gets to a vibration check point, keep the speed for one minute before you measure the vibration. (4) Measure the engine speeds (AS1, AS2, AS3), vibration amounts (AV1, AV2, AV3) and angles (AD1, AD2, AD3) in LP order at the three vibration check points and write on the Table 3.
(5) Go back to MIN IDLE for five minutes.
(6) Do a shutdown by the Discontinued Start, Restart and Shutdown Procedures (Ref. AMM TASK 71-00-00-710-018).
C. Examine the Following Vibration Peaks which are Measured and Recorded in Step A.
For the limits, refer (Ref. AMM TASK 71-00-00-860-010), engine operation limits, guidelines and special procedures, section "Vibration Limits and Fan Trim Balance Vibration Guidelines"
(1) N1/N2 vibration peaks.
(2) N1/N2 speeds at which the vibration peaks occurred.
Subtask 71-00-00-750-082-A ** ON A/C NOT FOR ALL For the limits, refer (Ref. AMM TASK 71-00-00-860-010), engine operation limits, guidelines and special procedures, section "Vibration Limits and Fan Trim Balance Vibration Guidelines"
(1) N1/N2 vibration peaks.
(2) N1/N2 speeds at which the vibration peaks occurred.
D. Prepare the Trial Trim Balance Weight
(1) Use the three trial trim balance weights, Fig. Item No.(14). identification No.5A0014 on Table 4.
Subtask 71-00-00-941-074-A ** ON A/C NOT FOR ALL (1) Use the three trial trim balance weights, Fig. Item No.(14). identification No.5A0014 on Table 4.
NOTE: The trial trim balance weight is the same as the trim balance weight, Fig. Item No.(14), identification No.5A0014.
E. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
Subtask 71-00-00-941-075-A ** ON A/C NOT FOR ALL (1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
F. Put the Ground Support Equipment in Position
(1) Put the ACCESS PLATFORM 1M(3 FT) into position to give access to the engine.
(2) Put the MAT - WORK in the air intake cowl.
Subtask 71-00-00-420-066-A ** ON A/C NOT FOR ALL (1) Put the ACCESS PLATFORM 1M(3 FT) into position to give access to the engine.
(2) Put the MAT - WORK in the air intake cowl.
NOTE: Make sure that the red warning pennants of the workmat can be seen externally.
Make sure that the workmat has sufficient dimensions to give full protection to the lower, half of the air intake cowl.
Make sure that the workmat has sufficient dimensions to give full protection to the lower, half of the air intake cowl.
G. Install trial trim balance weights to the bolts (16) which secure the inlet cone (19) to the front blade retaining ring (5) (Ref. AMM TASK 72-38-11-000-010).
(1) Make temporary marks on the front blade retaining ring with marker (Material No.V06-069) to identify the positions of the trim balance weights and the inlet cone fairing.
(a) As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(2) Remove the six bolts (17) and the inlet cone fairing (18) from the inlet cone (19).
(3) Decide the position where the three trial balance weights are to be installed.
(a) Find three consecutive bolts where the trial balance weights will be installed to compensate unbalance moment of the fan rotor from the Table 2 and 3.
(4) Find the positions at which you install the three trial trim balance weights.
(a) Make sure of the angular position AD1 which was measured in step B.(4).
The angular position AD1 was recorded on Table 3.
(6) Install the three trial balance weights (14) to the inlet cone with the three bolts.
(Ref. AMM TASK 70-23-11-911-013).
(8) Measure angle ADo counterclockwise from the timing mark to the center of the three trial balance weights.
(9) Write the angular positon ADo on the Table 7A.
(10) Install the inlet cone fairing (18).
(a) Put the inlet cone fairing in to original position on the inlet cone.
(b) Install the six bolts (17) and TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) (Ref. AMM TASK 70-23-11-911-013).
Subtask 71-00-00-942-060-A ** ON A/C NOT FOR ALL (1) Make temporary marks on the front blade retaining ring with marker (Material No.V06-069) to identify the positions of the trim balance weights and the inlet cone fairing.
(a) As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(2) Remove the six bolts (17) and the inlet cone fairing (18) from the inlet cone (19).
(3) Decide the position where the three trial balance weights are to be installed.
(a) Find three consecutive bolts where the trial balance weights will be installed to compensate unbalance moment of the fan rotor from the Table 2 and 3.
(4) Find the positions at which you install the three trial trim balance weights.
(a) Make sure of the angular position AD1 which was measured in step B.(4).
The angular position AD1 was recorded on Table 3.
NOTE: It is recommended that you install the trial trim balance weights near the angular position AD1 because it is considered that the angular AD1 is the unbalance position (lightest amount).
(b) Find three consecutive bolts which are near the angular position AD1. NOTE: The trial trim balance weight cannot be installed at the position which the existing trim balance weights are already installed.
(5) Remove the three bolts (15) and washers (16) from the inlet cone. (6) Install the three trial balance weights (14) to the inlet cone with the three bolts.
NOTE: Do not install the washer (15) at the bolt hole where the trim balance weight is installed.
(7) Torque the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) (Ref. AMM TASK 70-23-11-911-013). (8) Measure angle ADo counterclockwise from the timing mark to the center of the three trial balance weights.
(9) Write the angular positon ADo on the Table 7A.
(10) Install the inlet cone fairing (18).
(a) Put the inlet cone fairing in to original position on the inlet cone.
(b) Install the six bolts (17) and TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN )
(Ref. AMM TASK 70-23-11-911-013). H. Remove the Ground Support Equipment
(1) Remove the workmat from the air intake cowl.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
Subtask 71-00-00-750-083-A ** ON A/C NOT FOR ALL (1) Remove the workmat from the air intake cowl.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
I. Measure the Vibration at the Vibration Check Points on the Table 5
(2) Measure and write the vibration at the vibration check points.
Write the data on the Table 5.
(3) Go back to MIN IDLE for six minutes.
(4) Do a shutdown by the discontinued start, restart and shutdown procedures (Ref. AMM TASK 71-00-00-710-018).
Subtask 71-00-00-941-076-A ** ON A/C NOT FOR ALL CAUTION:
OPERATE BOTH ENGINES FOR THIS TEST. POWER DIFFERENCE BETWEEN TWO ENGINES CAN MAKE THE AIRCRAFT UNSTABLE.
CAUTION:
DO NOT INCREASE ENGINE SPEED TO MORE THAN 85 PERCENT (4803 RPM) N1. EXCESSIVE ENGINE SPEED CAN CAUSE AIRCRAFT BUFFET.
(1) Do Test No.8 (Ref. AMM TASK 71-00-00-700-022). (2) Measure and write the vibration at the vibration check points.
Write the data on the Table 5.
(3) Go back to MIN IDLE for six minutes.
(4) Do a shutdown by the discontinued start, restart and shutdown procedures (Ref. AMM TASK 71-00-00-710-018).
J. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
Subtask 71-00-00-941-077-A ** ON A/C NOT FOR ALL (1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
K. Put the Ground Support Equipment in to Position
(1) Put the ACCESS PLATFORM 1M(3 FT) in to position to give access to the engine.
(2) Put the MAT - WORK in the air intake cowl.
Subtask 71-00-00-020-062-A ** ON A/C NOT FOR ALL (1) Put the ACCESS PLATFORM 1M(3 FT) in to position to give access to the engine.
(2) Put the MAT - WORK in the air intake cowl.
NOTE: Make sure that the red warning pennants of the workmat can be seen externally.
Make sure that the workmat has sufficient dimensions to give full protection to the lower, half of the air intake cowl.
Make sure that the workmat has sufficient dimensions to give full protection to the lower, half of the air intake cowl.
L. Remove the Trial Balance Weights
(1) Remove the six bolts (17) and the inlet cone fairing (18) from the inlet cone (19) (Ref. AMM TASK 72-38-11-000-010).
(2) Remove the three bolts (16) which attach the trial balance weights to the inlet cone.
(3) Replace each trial balance weight with a washer (15).
(Ref. AMM TASK 70-23-11-911-013).
Subtask 71-00-00-750-084-A ** ON A/C NOT FOR ALL (1) Remove the six bolts (17) and the inlet cone fairing (18) from the inlet cone (19) (Ref. AMM TASK 72-38-11-000-010).
(2) Remove the three bolts (16) which attach the trial balance weights to the inlet cone.
(3) Replace each trial balance weight with a washer (15).
NOTE: The washer (15) must be installed at the bolt hole where a trim balance weight is not installed.
(4) Safety the washers with the bolts (16) and TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) (Ref. AMM TASK 70-23-11-911-013). M. Calculate the Trim Balance Effect Vectors at the Three Speeds
(1) Write the vector AV1 and AV4 on a polar coordinates, DIAGRAM 1.
(2) Write the vector AV2 and AV5 on a polar coordinates, DIAGRAM 2.
(3) Write the vector AV3 and AV6 on a polar coordinates, DIAGRAM 3.
(4) Get the vector AC1 and the angle AB1 on the polar coordinates, DIAGRAM 1.
(5) Get the vector AC2 and the angle AB2 on the polar coordinates, DIAGRAM 2.
(6) Get the vector AC3 and the angle AB3 on the polar coordinates, DIAGRAM 3.
(7) Calculate the required balance effect vectors AW1, AW2 and AW3.
(a) The amounts of the vectors AW1, AW2 and AW3 are calculated with the following equations.
(b) The directions of the vectors AW1, AW2 and AW3 are found as follows:
Subtask 71-00-00-750-085-A ** ON A/C NOT FOR ALL (1) Write the vector AV1 and AV4 on a polar coordinates, DIAGRAM 1.
(2) Write the vector AV2 and AV5 on a polar coordinates, DIAGRAM 2.
(3) Write the vector AV3 and AV6 on a polar coordinates, DIAGRAM 3.
(4) Get the vector AC1 and the angle AB1 on the polar coordinates, DIAGRAM 1.
(5) Get the vector AC2 and the angle AB2 on the polar coordinates, DIAGRAM 2.
(6) Get the vector AC3 and the angle AB3 on the polar coordinates, DIAGRAM 3.
(7) Calculate the required balance effect vectors AW1, AW2 and AW3.
(a) The amounts of the vectors AW1, AW2 and AW3 are calculated with the following equations.
| Total amount TM0 = Moment effect of the three trial trim balance weights (Fig. |
| Item No.(14), 5A0014) |
| = 6.546 oz. in (4714 g mm) |
| LENGTH AV1 |
| Amount AW1 = TM0 (6,546 oz. in) x ---------- |
| LENGTH AC1 |
| LENGTH AV2 |
| Amount AW2 = TM0 (6,546 oz. in) x ---------- |
| LENGTH AC2 |
| LENGTH AV3 |
| Amount AW3 = TM0 (6,546 oz. in) x ---------- |
| LENGTH AC3 |
(b) The directions of the vectors AW1, AW2 and AW3 are found as follows:
| direction AW1 : Counterclockwise turned from the trial trim weight direction |
| by angle AB1 that is the counterclockwise angle from AC1 to |
| AV1. |
| direction AW2 : Counterclockwise turned from the trial trim weight direction |
| by angle AB2 that is the counterclockwise angle from AC2 to |
| AV2. |
| direction AW3 : Counterclockwise turned from the trial trim weight direction |
| by angle AB3 that is the counterclockwise angle from AC3 to |
| AV3. |
N. Calculate the Required Trim Balance Weight which is Calculated from Vector Average of Vectors AW1, AW2 and AW3
(1) Calculate vector sum of vectors AW1, AW2 and AW3.
(a) Make lines of vectors AW1, AW2 and AW3 on DIAGRAM 4 as following sequence.
(b) Get vector sum AW4 and angle AB4. Vector AW4 starts at the root of AW1 and stops at the tip of AW3. AB4 is the counterclockwise angle from datum line to vector AW4.
(2) Calculate the necessary trim balance weight W to correct unbalance.
Subtask 71-00-00-750-086-A ** ON A/C NOT FOR ALL (1) Calculate vector sum of vectors AW1, AW2 and AW3.
(a) Make lines of vectors AW1, AW2 and AW3 on DIAGRAM 4 as following sequence.
| ---------------------------------------------------------------------------- |
| ! ! Start Point ! Direction ! |
| !--------------!----------------------!------------------------------------! |
| ! AW1 ! _ ! Counter clockwise ! |
| ! ! ! angle AB1 from datum ! |
| !--------------!----------------------!------------------------------------! |
| ! AW2 ! end of AW1 ! Counter clockwise ! |
| ! ! ! angle AB2 from datum ! |
| !--------------!----------------------!------------------------------------! |
| ! AW3 ! end of AW2 ! Counter clockwise ! |
| ! ! ! angle AB3 from datum ! |
| ---------------------------------------------------------------------------- |
(b) Get vector sum AW4 and angle AB4. Vector AW4 starts at the root of AW1 and stops at the tip of AW3. AB4 is the counterclockwise angle from datum line to vector AW4.
(2) Calculate the necessary trim balance weight W to correct unbalance.
| AW4 length 1 |
| W oz = ------------------ X ----------- |
| 3 7.913 |
| AW4 length 1 |
| W gm = ------------------ X ----------- |
| 3 201.00 |
NOTE: Half of PCD of the bolt holes to install the trim balance weights is 7.913 in. (200.99 mm).
(3) Get the necessary angle AK in the counterclockwise direction from the timing mark on the front retaining ring. | AK = ADo (counterclockwise angle from timing mark to trial trim balance |
| weight position) |
| + |
| AB4 (counterclockwise angle from the datum line to the vector AW4) |
O. Find the Flange at which the Trim Balance Weight is to be Installed
(1) When the weight W is less than 1 oz (28.3 g), you can balance the LP compressor with trim balance weight (10), (11), (12), (13) and (14) after removal of the inlet cone fairing (18).
If so, do Step T.
(2) When the weight W is over 1 oz (28.3 g), you can balance LP compressor with trim balance weight (1), (2), (3), and/or (4) after removal of the inlet cone fairing (18) and the inlet cone (19).
If so, do Step U.
Subtask 71-00-00-420-067-A ** ON A/C NOT FOR ALL (1) When the weight W is less than 1 oz (28.3 g), you can balance the LP compressor with trim balance weight (10), (11), (12), (13) and (14) after removal of the inlet cone fairing (18).
If so, do Step T.
(2) When the weight W is over 1 oz (28.3 g), you can balance LP compressor with trim balance weight (1), (2), (3), and/or (4) after removal of the inlet cone fairing (18) and the inlet cone (19).
If so, do Step U.
P. Install the Trim Balance Weights to the Inlet Cone Flange
(1) Make sure that the inlet cone fairing is not installed on the inlet cone.
(a) Find the trim balance weights and positions with W, FA and Table 7.
(b) Find the trim balance weights with the result of Step T. (2) (a) and Table 4.
(a) Suppose that the necessary trim balance weight W is calculated in step P.(2) 12.7 gm and that the required trim angular position AK is 321 degrees.
(b) Suppose that bolt holes "A" are 45, 105, 165, 225, 285 and 345 degrees counterclockwise apart from the timing mark.
(d) Find bolt hole "A" near to the unbalance phase, in a clockwise direction looking from the front of the engine.
The bolt hole "A" which is 105 degrees apart from the timing mark is selected.
(e) Give the numbers N1 to N24 to the bolt holes. N1 must be given to the hole "A" found in step (d). The remaining numbers must be identified in counterclockwise direction when you look from the engine front.
(f) Calculate the unbalance phase angle FA.
(g) Find the nearest unbalance amplitude on Table 7 to the W (12.7 gm).
The nearest unbalance amplitude = 15 gm
(h) Find the nearest unbalance phase angle FA on Table 7 to FA (36 degrees) found in Step (f).
The nearest unbalance phase angle FA = 35 degrees.
(i) Find the trim balance weights and positions from Table 7 Sheet 4 with 15 gm and 35 degrees.
The following data are found.
N4-11
N6-11
N15-14
N16-14
(j) The found trim balance weights and positions are shown on illustration.
(4) Install the trim balance weight at the position and install the inlet cone fairing (Ref. AMM TASK 72-38-11-400-010).
(a) To find the position where you are to install the trim balance weights, count bolt hole numbers.
Start at the bolt hole No.N1, which is near to unbalance phase, and go counterclockwise, when you look from the engine front.
(b) Make a mark on the front blade retaining ring with a marker (Material No.V06-069) to identify the positions of the trim balance weights.
1 As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(c) Remove the bolt (16) and the washer (15) at the found position. Remove the trim balance weight, if it was already installed at the position.
(d) Make sure of the identification mark and the weight value of each trim balance weight.
(e) Install the trim balance weight (10), (11), (12), (13) and/or (14) with the bolt (16) to the found positions.
(Ref. AMM TASK 70-23-11-911-013).
(g) Install the inlet cone fairing (18) and the six bolts (17).
(h) TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) (Ref. AMM TASK 70-23-11-911-013).
(5) Go to Step T.
Subtask 71-00-00-420-068-A ** ON A/C NOT FOR ALL (1) Make sure that the inlet cone fairing is not installed on the inlet cone.
NOTE: The inlet cone fairing was removed in Step K.
(2) Find the trim balance weights and positions. (a) Find the trim balance weights and positions with W, FA and Table 7.
(b) Find the trim balance weights with the result of Step T. (2) (a) and Table 4.
NOTE: If another trim balance weight (Fig. item No. (10), (11), (12), (13) and/or (14)) was already installed at the same position where you require to install the trim balance weight, add the weight value to the value found in step (a). Install the trim balance weight of a value equal to the sum.
Do not install more than one trim balance weight at one position.
(3) Example: Do not install more than one trim balance weight at one position.
(a) Suppose that the necessary trim balance weight W is calculated in step P.(2) 12.7 gm and that the required trim angular position AK is 321 degrees.
(b) Suppose that bolt holes "A" are 45, 105, 165, 225, 285 and 345 degrees counterclockwise apart from the timing mark.
NOTE: The bolt holes "A" are the holes where the bolts, which attach the inlet cone fairing, are installed.
(c) Calculate the unbalance phase angle FB. | FB = AK - 180 |
| = 321 - 180 |
| = 141 degrees |
(d) Find bolt hole "A" near to the unbalance phase, in a clockwise direction looking from the front of the engine.
The bolt hole "A" which is 105 degrees apart from the timing mark is selected.
(e) Give the numbers N1 to N24 to the bolt holes. N1 must be given to the hole "A" found in step (d). The remaining numbers must be identified in counterclockwise direction when you look from the engine front.
(f) Calculate the unbalance phase angle FA.
| FA = FB - 105 |
| = 141 - 105 |
| = 36 degrees |
(g) Find the nearest unbalance amplitude on Table 7 to the W (12.7 gm).
The nearest unbalance amplitude = 15 gm
(h) Find the nearest unbalance phase angle FA on Table 7 to FA (36 degrees) found in Step (f).
The nearest unbalance phase angle FA = 35 degrees.
(i) Find the trim balance weights and positions from Table 7 Sheet 4 with 15 gm and 35 degrees.
The following data are found.
N4-11
N6-11
N15-14
N16-14
(j) The found trim balance weights and positions are shown on illustration.
(4) Install the trim balance weight at the position and install the inlet cone fairing (Ref. AMM TASK 72-38-11-400-010).
(a) To find the position where you are to install the trim balance weights, count bolt hole numbers.
Start at the bolt hole No.N1, which is near to unbalance phase, and go counterclockwise, when you look from the engine front.
(b) Make a mark on the front blade retaining ring with a marker (Material No.V06-069) to identify the positions of the trim balance weights.
1 As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(c) Remove the bolt (16) and the washer (15) at the found position. Remove the trim balance weight, if it was already installed at the position.
(d) Make sure of the identification mark and the weight value of each trim balance weight.
(e) Install the trim balance weight (10), (11), (12), (13) and/or (14) with the bolt (16) to the found positions.
NOTE: Do not install the washer (15) at the bolt hole where the trim balance weight is installed.
(f) TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) (Ref. AMM TASK 70-23-11-911-013). (g) Install the inlet cone fairing (18) and the six bolts (17).
(h) TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN )
(Ref. AMM TASK 70-23-11-911-013). (5) Go to Step T.
Q. Install the Trim Balance Weights to the Front Blade Retaining Ring
(1) Remove the inlet cone fairing and the inlet cone from the front blade retaining ring (Ref. AMM TASK 72-38-11-000-010).
(a) Mark temporarily the position of the trim balance weight (10), (11), (12), (13) and/or (14) on the front blade retaining ring (5) with marker (Material No.V06-069) , if it is installed.
1 As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(b) Remove 18 bolts (16) and washers (15), trim balance weight (10), (11), (12), (13) and/or (14), if it is installed, and the inlet cone (19) from the front blade retaining ring (5).
(2) Find the trim balance weights and positions.
(a) Calculate the unbalance amplitude (required trim balance weight) WF on the front blade retaining ring.
FB (degrees) = AK - 180
(c) Find the trim balance weights and positions with WF, FB and Table 8.
(a) Suppose that the required trim balance weight W calculated in Step R. (2) is 28.4 gm and that required angular position AK is 241 degrees.
(b) Calculate the required trim balance weight WF on the front blade retaining ring flange.
(c) Calculate the unbalance phase angle FB.
(d) Find the nearest unbalance amplitude on Table 8 to the W (34.0 gm).
The nearest unbalance amplitude = 30 gm
(e) Find the nearest unbalance phase angle FB on Table 8 to FB (61 degrees) found in Step (c).
The nearest unbalance phase angle FB = 60 degrees.
(f) Find the trim balance weights and positions from Table 8 Sheet 18 with 30 gm and 60 degrees.
The following data are found.
H24-2
H25-4
H28-1
(g) The found trim balance weights and positions are shown on Table 6.
(4) Install the trim balance weights at the position (Ref. AMM TASK 72-38-11-400-010).
(a) To find the position where it is necessary, to install the trim balance weight- count holes counterclockwise from the timing mark on the front blade retaining ring and mark the position on the front blade retaining ring with marker (Material No.V06-069) .
1 As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(b) Remove the bolts (20) at the found position. Remove the trim balance weight, if it was already installed at the found position.
(c) Make sure of the identification mark and the weights value of each trim balance weight.
(d) Install the trim balance weight (1), (2), (3) and/or (4) with the bolt (20).
(e) TORQUE the bolt to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) (Ref. AMM TASK 70-23-11-911-013).
(5) Install the inlet cone (19) and inlet cone fairing (18) (Ref. AMM TASK 72-38-11-400-010).
(a) Install the inlet cone (19), the trim balance weight (10), (11), (12), (13) and/or (14), if it was removed in Step U. (1), and the 18 bolts (16).
.
(c) Install the inlet cone fairing, the trim balance weight (10), (11), (12), (13) and/or (14), if it was removed in Step P. (1), and the six bolts (17).
(d) TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ).
Subtask 71-00-00-942-061-A ** ON A/C NOT FOR ALL (1) Remove the inlet cone fairing and the inlet cone from the front blade retaining ring (Ref. AMM TASK 72-38-11-000-010).
(a) Mark temporarily the position of the trim balance weight (10), (11), (12), (13) and/or (14) on the front blade retaining ring (5) with marker (Material No.V06-069) , if it is installed.
1 As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(b) Remove 18 bolts (16) and washers (15), trim balance weight (10), (11), (12), (13) and/or (14), if it is installed, and the inlet cone (19) from the front blade retaining ring (5).
(2) Find the trim balance weights and positions.
(a) Calculate the unbalance amplitude (required trim balance weight) WF on the front blade retaining ring.
| WF = W x 7.913/6.540 = W x 1.210 |
NOTE: 6.540 in. (166.11 mm) is half of PCD of the bolt holes in the retaining ring.
NOTE: W is calculated in step P.(2).
(b) Calculate the unbalance phase angle FB. FB (degrees) = AK - 180
(c) Find the trim balance weights and positions with WF, FB and Table 8.
NOTE: The first element of HXX-XX on Table 8 shows bolt hole No. The second element shows Fig. Item No. of trim balance weight.
H21-4, for example, shows bolt hole No. 21 and weight (4), (25.0 gm).
(d) Find the trim balance weights with the result of Step W. (2) (c) and Table 6. H21-4, for example, shows bolt hole No. 21 and weight (4), (25.0 gm).
NOTE: If another trim balance weight (Fig. Item No. (1), (2), (3) and/or (4)), was already installed at the same position where it is necessary to install the trim balance weight, add the weight value to the value found in Step (c). Install a trim balance weight of a value equal to the sum.
Do not install more than one trim balance weight at one position.
Do not install more than one trim balance weight at one position.
NOTE: Do not install more than one trim balance weight at one position.
(3) Example: (a) Suppose that the required trim balance weight W calculated in Step R. (2) is 28.4 gm and that required angular position AK is 241 degrees.
(b) Calculate the required trim balance weight WF on the front blade retaining ring flange.
| WF = W x 1.210 |
| = 28.4 x 1.210 |
| = 34.0 gm |
(c) Calculate the unbalance phase angle FB.
| FB = AK - 180 |
| = 241 - 180 |
| = 61 degrees |
(d) Find the nearest unbalance amplitude on Table 8 to the W (34.0 gm).
The nearest unbalance amplitude = 30 gm
(e) Find the nearest unbalance phase angle FB on Table 8 to FB (61 degrees) found in Step (c).
The nearest unbalance phase angle FB = 60 degrees.
(f) Find the trim balance weights and positions from Table 8 Sheet 18 with 30 gm and 60 degrees.
The following data are found.
H24-2
H25-4
H28-1
(g) The found trim balance weights and positions are shown on Table 6.
(4) Install the trim balance weights at the position (Ref. AMM TASK 72-38-11-400-010).
(a) To find the position where it is necessary, to install the trim balance weight- count holes counterclockwise from the timing mark on the front blade retaining ring and mark the position on the front blade retaining ring with marker (Material No.V06-069) .
1 As an alternative to the marker (Material No.V06-069) , it is permitted to use a marker that is specified in IAE V2500 Standard Practices Manual (SPP-V2500-1IA) 70-09-01-400-501 - Procedure To Make Temporary Marks On Components And Assemblies.
(b) Remove the bolts (20) at the found position. Remove the trim balance weight, if it was already installed at the found position.
(c) Make sure of the identification mark and the weights value of each trim balance weight.
(d) Install the trim balance weight (1), (2), (3) and/or (4) with the bolt (20).
(e) TORQUE the bolt to between 220 and 180 lbf.in (2.49 and 2.03 m.daN )
(Ref. AMM TASK 70-23-11-911-013). (5) Install the inlet cone (19) and inlet cone fairing (18) (Ref. AMM TASK 72-38-11-400-010).
(a) Install the inlet cone (19), the trim balance weight (10), (11), (12), (13) and/or (14), if it was removed in Step U. (1), and the 18 bolts (16).
NOTE: Install the washer (15) at the bolt hole where a trim balance weight is not installed. Do not install the washer at the bolt hole where the trim balance weight is installed.
(b) TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN ) . (c) Install the inlet cone fairing, the trim balance weight (10), (11), (12), (13) and/or (14), if it was removed in Step P. (1), and the six bolts (17).
(d) TORQUE the bolts to between 220 and 180 lbf.in (2.49 and 2.03 m.daN )
. R. Remove the ground support equipment.
(1) Remove the workmat from the air intake cowl.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
Subtask 71-00-00-750-087-A ** ON A/C NOT FOR ALL (1) Remove the workmat from the air intake cowl.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
S. Test Engine
CAUTION:
OPERATE BOTH ENGINES FOR THIS TEST. POWER DIFFERENCE BETWEEN TWO ENGINES CAN MAKE THE AIRCRAFT UNSTABLE.
CAUTION:
DO NOT INCREASE ENGINE SPEED TO MORE THAN 85 PERCENT (4803 RPM) N1. EXCESSIVE ENGINE SPEED CAN CAUSE AIRCRAFT BUFFET.
(1) Do Test No.8 (Ref. AMM TASK 71-00-00-700-022) and make sure that the vibration is in the limits listed in (Ref. AMM TASK 71-00-00-860-010), engine operation limits, guidelines and special procedures, section "Vibration Limits and Fan Trim Balance Vibration Guidelines".