Replacement of Individual Fan Blades [CFMB]

TASK 72-21-00-300-029-A
Replacement of Individual Fan Blades

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE
No specific	1	MAT - PROTECTIVE
No specific	1	MAT - RUBBER
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 )
856A3770	1	CFMI SOFTWARE FOR BLADE MAPPING

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP5061)	temporary marking
(Material No.CP5062)	MOS2 dry film lubricant

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-710-009-B	Vibration Check
TASK 71-00-00-750-001-B	Fan Trim Balance - 1 Sensor 3 Speed
TASK 71-00-00-750-001-B-03	Fan Trim Balance - 1 Sensor 1 Speed
TASK 72-21-00-000-005-A	Removal of the Spinner Front Cone
TASK 72-21-00-000-006-A	Removal of the Spinner Rear Cone
TASK 72-21-00-000-007-A	Removal of the Fan Rotor Blades
TASK 72-21-00-400-005-A	Installation of the Spinner Front Cone
TASK 72-21-00-400-006-A	Installation of the Spinner Rear Cone
TASK 72-21-00-400-007-A	Installation of the Fan Rotor Blades
Fan Blade Replacement
Various Balance Screw Arrangements for Given Moment Weights
Balance Screws
Diagram for Fan Blade Change in Individual

3. Job Set-up
Subtask 72-21-00-941-086-A ** ON A/C NOT FOR ALL

A. 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).
(4) Put an ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE in position.
(5) Install MAT - PROTECTIVE in the lower half of the inlet cowl.

4. Procedure
Subtask 72-21-00-020-076-A ** ON A/C NOT FOR ALL

CAUTION: DO NOT MIX PAIRS OF BLADES PRE CFM SB 72-0057 AND POST CFM SB 72-0057 ON THE SAME FAN DISK.

A. Record moment weight of blades.

NOTE: If pairs of fan blades are not available as spare, you can replace one blade individually. If the result of the fan blade plotting is not correct, you must do the inspections and corrections given below before and after the fan blade installation to make sure the engine imbalance is not more than the limits. This will also optimize the engine operation. Three conditions can exist, refer to the logic dynamic.

Diagram for Fan Blade Change in Individual ** ON A/C NOT FOR ALL

NOTE: In all cases of individual blade replacement, remove its opposite to record the moment weight of the opposite blade.

(1) Put a MAT - RUBBER in the air intake cowl.
(2) Remove the spinner front cone (Ref. AMM TASK 72-21-00-000-005).
(3) Remove the spinner rear cone (Ref. AMM TASK 72-21-00-000-006).
(4) Remove the balance screws and record their location.
(5) Record moment weight of removed blade using.
(6) Remove fan blade (Ref. AMM TASK 72-21-00-000-007).

Subtask 72-21-00-750-055-A ** ON A/C NOT FOR ALL

B. Record the moment weight of the spare blade and install the fan blade.
(1) Record the moment weight of the blade to be installed using temporary marking (Material No.CP5061) .
(2) Do a check and record the moment weight difference between the blade to be installed and the opposite blade.
(a) If the quantity of an individual blade change is less than or equal to three and if the moment weight with the opposite blade is less than 200 cm.g (80 in.g):
1 No correction is necessary.
2 Install the spare blades (Ref. AMM TASK 72-21-00-400-007).
3 Vibration survey is not necessary.
(b) If the difference between moment weights "D" is more than 200 cm.g (80 in.g), do as follows:
1 Do a static correction, given in procedure paragraph C., or do a blade mapping with 856A3770 CFMI SOFTWARE FOR BLADE MAPPING.
2 Install the spare blades (Ref. AMM TASK 72-21-00-400-007).
3 Go to paragraph D.
(c) If you change more than three fan blades, do as follows:
1 Do a static correction procedure given in paragraph C. or do a blade mapping with 856A3770 CFMI SOFTWARE FOR BLADE MAPPING.
2 Install the spare blades (Ref. AMM TASK 72-21-00-400-007).
3 Go to paragraph D.

Subtask 72-21-00-820-055-A ** ON A/C NOT FOR ALL

C. Static correction procedure. Determine the balance screws to be installed.
(1) Assume a blade with moment weight of 162750 cm.g (64075 in.g) is to be replaced in any position.
(2) A spare blade is provided with moment weight of 163296 cm.g (64290 in.g).
(3) Calculate the difference between the moment weights as below:
163296 - 162750 = 546 cm.g (215 in.g).
(4) Select the balance screws as follows:

Various Balance Screw Arrangements for Given Moment Weights ** ON A/C NOT FOR ALL

(a) Determine the solutions closest to the above difference of 546 cm.g (215 in.g).
The example corresponds to one centered screw P05 and two lateral screws P01 = 541 cm.g (213 in.g). This "correction A" permits a satisfactory correction for returning the fan near its initial balance condition.
(5) Locate the balance screws as follows:
(a) If the new blade is heavier than the removed blade, install the balance screws near the opposite blade.
(b) If the new blade is lighter than the removed blade, install the balance screw near to the removed blade.

NOTE: Balance screws are identified by a number corresponding to their moment weight (P01-P02-P03-P04-P05-P06-P07) engraved on screw head. As it may be difficult to read the numbers due to erosion and pollution, the relationship between the screw reference and screw length is shown in figure.

Balance Screws ** ON A/C NOT FOR ALL

(6) Install balance screws.
(a) Remove the P07 screws installed on the spinner rear cone and install the balance screws given in paragraph C.4 "correction A" with a thin layer of MOS2 dry film lubricant (Material No.CP5062) . TORQUE the screws to between 75 and 65 lbf.in (0.85 and 0.73 m.daN )

.
(b) If the balance screws to be removed are not P07, do as follows:
1 Determine the installed correction on the spinner rear cone, "correction B".

Various Balance Screw Arrangements for Given Moment Weights ** ON A/C NOT FOR ALL

2 Compute "correction C" (gr.in/gr.cm) = A (gr.in/gr.cm) + B (gr.in/gr.cm).
3 Determine balance screws of correction C.

Various Balance Screw Arrangements for Given Moment Weights ** ON A/C NOT FOR ALL

4 Remove the balance screws installed on spinner rear cone and prepare the balance screws "correction C" for installation.

Subtask 72-21-00-820-056-A ** ON A/C NOT FOR ALL

D. Vibration Survey
(1) Install the spinner rear cone (Ref. AMM TASK 72-21-00-400-005).
(2) Install the balance screws lightly coated with a thin layer of MOS2 dry film lubricant (Material No.CP5062) on the spinner rear cone. TORQUE the screws to between 75 and 65 lbf.in (0.85 and 0.73 m.daN )

. If you did the blade mapping with 856A3770 CFMI SOFTWARE FOR BLADE MAPPING, install a complete set of balance screws P07.
(3) Install the spinner front cone (Ref. AMM TASK 72-21-00-400-006).
(4) Remove the MAT - RUBBER from the inlet cowl.
(5) Do the vibration check (Ref. AMM TASK 71-00-00-710-009) if:
(a) You installed a new fan blade mapping.
(b) You did the static correction for more than three blades replacement.
(6) If the vibration level is out of the limits, do a trim balance (Ref. AMM TASK 71-00-00-750-001).

Diagram for Fan Blade Change in Individual ** ON A/C NOT FOR ALL

5. Close-up
Subtask 72-21-00-869-081-A ** ON A/C NOT FOR ALL

A. Make sure that the work area is clean and clear of tools and other items.

Subtask 72-21-00-942-079-A ** ON A/C NOT FOR ALL

B. Close Access
(1) Remove the MAT - PROTECTIVE from the inlet cowl.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 12:59:43 UTC