Fan Trim Balance with the EVMU (Vectorial Method) [CFMI]

TASK 77-32-34-750-002-A-01
Fan Trim Balance with the EVMU (Vectorial Method)

1. Reason for the Job
You can use this procedure when consecutive fan trim balances with the EVMU when you use the one shot method did not give significant results. In all other cases the one shot method is recommended.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 75 and 65 lbf.in (0.85 and 0.73 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP5062)	MoS_2 dry film lubricant

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 31-32-00-860-012-A	Procedure to Get Access to the SYSTEM REPORT/TEST/ENG Page
TASK 77-32-34-869-042-A	Acquire Unbalance Data During the Flight and Read Unbalance Data
TASK 77-32-34-869-043-A	Unbalance Parameter Acquisition on the Ground
Trim Balance - Vectorial Method

3. Job Set-up
Subtask 77-32-34-861-074-A ** ON A/C NOT FOR ALL

A. Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).

Subtask 77-32-34-865-083-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	ENGINE/ENG1 AND 2/EVMU	1EV	R44

Subtask 77-32-34-941-056-A ** ON A/C NOT FOR ALL

C. 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 77-32-34-860-070-A ** ON A/C NOT FOR ALL

D. Aircraft System Configuration
(1) On the spinner rear cone, record the identification (P0X) and the position of all the 36 balance screws.

NOTE: The balance screws are identified by a number (P0X) engraved on the screw head.

NOTE: A spherical mark is machined on the spinner rear cone to show the fan blade No.1 location. The fan blade No.1 is to the left of the mark, forward looking aft (the blades are counted counterclockwise).

Subtask 77-32-34-869-105-A ** ON A/C NOT FOR ALL

E. Aircraft Maintenance Configuration
(1) To do this procedure flight or ground vibration data must be available (Ref. AMM TASK 77-32-34-869-042) or (Ref. AMM TASK 77-32-34-869-043).
(2) On the MCDU 1(2), get the SYSTEM REPORT/TEST ENG page (Ref. AMM TASK 31-32-00-860-012).
(3) Push the key adjacent to the EVMU indication: the first EVMU page comes into view.
(4) Push the NEXT PAGE key.
(5) Push the key adjacent to the ENGINE UNBALANCE indication
(6) The EVMU ENGINE UNBALANCE menu comes into view.

4. Procedure
Subtask 77-32-34-750-055-A ** ON A/C NOT FOR ALL

A. Do the fan trim balance.

ACTION	RESULT
1.Push the line key adjacent to the ENG1(2) TRIM indication.	The EVMU ENG1(2) TRIM BALANCE menu comes into view.
2.Push the line key adjacent to the VECTORIAL TRIM BALANCE CFM56-5A indication.	The EVMU ENG1(2) VECTORIAL TRIM BAL menu comes into view.
3.Push the line key adjacent to the PREVIOUS DATA indication.	The EVMU ENG1(2) PREVIOUS INSTALLED SCREWS menu comes into view. Compare the data shown on the ENG1(2) PREVIOUS INSTALLED SCREWS menu with the data collected during the One Shot Trim Balancing procedure. If necessary update the data.
4.After the check of all the 36 holes/screw configurations, push the line key adjacent to the CONT indication.	The EVMU ENG1(2) PRE BEAR1 VIB INPUT menu comes into view. Compare the data shown on the MCDU screen with the data collected during the One Shot Trim Balancing procedure. If necessary update the data.
5.Push the line key adjacent to the CONT indication.	The EVMU ENG1(2) PRE TRF VIB INPUT menu comes into view. Compare the data shown on the MCDU screen with the data collected during the One Shot Trim Balancing procedure. If necessary update the data.
6.Push the line key adjacent to the CONT indication.	The EVMU ENG1(2) VECTORIAL TRIM BAL menu comes into view.
7.Push the line key adjacent to the SELECT CURRENT DATA indication.	The ENG1(2) CURRENT VIB INPUT menu comes into view.
8.Push the line key related to the data that you use to do the trim balance: FLIGHT DATA or GROUND DATA or MANUAL INPUT.
9.Push the line key adjacent to the CONT indication.	The ENG1(2) CURRENT INSTALLED SCREWS menu comes into view. Compare the data shown on the MCDU with the data collected in step D. for all the 36 holes and if necessary, type on the keyboard the current screw identification installed (P0X).
10.Push the line key adjacent to the CONT indication.	The ENG1(2) SCREWS TO CHANGE menu comes into view. Do a print of this page and if there is more than one page, on the MCDU keyboard, push the NEXT PAGE pushbutton and do a print of each page.
11.If you want to keep this new configuration push the line key adjacent to the UPDATE indication.
12.On the MCDU, push the line select key adjacent to the RETURN indication until the CFDS menu page comes into view.

(1) On the spinner rear cone change the balance screws as indicated.
(a) Lightly coat the balance screws with MoS_2 dry film lubricant (Material No.CP5062) .
(b) TORQUE balance screws to between 75 and 65 lbf.in (0.85 and 0.73 m.daN )

5. Close-up
Subtask 77-32-34-942-059-A ** ON A/C NOT FOR ALL

A. Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:17:11 UTC