Complementary (and optional) Borescope Inspection of the Booster Stage 4 Rotor Blade Tips Through One VBV Cavity. [CFMI]

TASK 72-21-00-290-002-A
Complementary (and optional) Borescope Inspection of the Booster Stage 4 Rotor Blade Tips Through One VBV Cavity.

FIN: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
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 95 and 85 lbf.in (1.07 and 0.96 m.daN )
856A1320	1	BORESCOPE-KIT
856A1322	1	BORESCOPE-LIGHT SOURCE SET
856A2501	1	WRENCH-VBV MANUAL CONTROL

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP2101)	graphite grease

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-A	Closing of the Fan Cowl Doors
TASK 72-21-00-290-001-A	Standard Borescope Inspection of Booster Rotor Blades, Stages 2, 3 and 4 through the Booster Inlet and Borescope Port SO
TASK 78-30-00-081-041-A	Make the Thrust Reverser Serviceable after Maintenance
TASK 78-30-00-481-041-A	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-A	Opening of the Thrust Reverser Doors
TASK 78-36-00-410-040-A	Closing of the Thrust Reverser Doors
Opening of VBV Door at 3:30 O'clock
Complementary Borescope Inspection of Stage 4 Rotor Blade Tips through One of the VBV Cavities

3. Job Set-up
Subtask 72-21-00-941-065-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).

Subtask 72-21-00-010-056-A ** ON A/C NOT FOR ALL

B. Open fan cowl doors: (Ref. AMM TASK 71-13-00-010-040)
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

Subtask 72-21-00-040-051-A ** ON A/C NOT FOR ALL

C. Make the thrust reverser unserviceable (Ref. AMM TASK 78-30-00-481-041).

Subtask 72-21-00-010-057-A ** ON A/C NOT FOR ALL

D. Open the thrust reverser doors: (Ref. AMM TASK 78-36-00-010-040)
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(a) FOR [1000EM2] (ENGINE-2)
461AL 462AR

4. Procedure

NOTE: This procedure is not an alternative to the standard inspection of the stage 4 rotor blades through the (single) borescope port SO. But, if necessary, it may complement the standard procedure (Ref. TASK 72-21-00-290-00100) because of the different rear-to-front viewing angles it gives to look at the stage 4 blades. In addition, it permits to make a visual estimate (even if partial) of the condition of the static parts in the booster discharge area, specially the visible vanes of stage 4 vane assembly.

Subtask 72-21-00-020-055-A ** ON A/C NOT FOR ALL

A. Loosen the 4 captive screws which attach the fan duct panel located between struts 4 and 5 (3:30 o'clock). Remove the panel.

Subtask 72-21-00-480-052-A ** ON A/C NOT FOR ALL

B. Use 856A2501 WRENCH-VBV MANUAL CONTROL (856A2501G01) at 3:30 to manually open the VBV door.

Opening of VBV Door at 3:30 O'clock ** ON A/C NOT FOR ALL

Subtask 72-21-00-480-051-A ** ON A/C NOT FOR ALL

C. Use a 856A1320 BORESCOPE-KIT (856A1320P04 or 856A1320P05) , (field of vision 60 deg., angle of vision 130 deg.) to have a view at the trailing edges and tips of stage 4 rotor blades.

NOTE: Depending on the operator's experience, you may instead use a fiberscope set, if available. Compared to the rigid borescope probe specified, you can move a fiberscope flexible end tip nearer to the stage 4 rotor blades (axially) and partially move it (radially) either side of them.

(1) It is necessary to index and turn the fan rotor. You can turn the fan/booster rotor from the engine inlet.
(2) Connect the power supply:

CAUTION: BEFORE YOU CONNECT THE POWER SUPPLY TO THE POWER SOURCE BE SURE THE ON-OFF SWITCH IS IN THE OFF POSITION AND LIGHT INTENSITY CONTROL IS SET TO MINIMUM. MAKE SURE THAT PROJECTOR AND POWER SUPPLY ARE CORRECTLY GROUNDED.

(a) Connect power supply to grounded power source.
(3) Connect fiber light cable to rigid borescope and to port on 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322P02 or 856A1322P03 or 856A1322P04 or 856A1322P08 or 856A1322P09).
(4) Turn light source on; insert borescope through open VBV door at 3:30 and position it as necessary for inspection.

Complementary Borescope Inspection of Stage 4 Rotor Blade Tips through One of the VBV Cavities ** ON A/C NOT FOR ALL

Subtask 72-21-00-290-051-A ** ON A/C NOT FOR ALL

WARNING: BE CAREFUL WHEN YOU TURN THE FAN ROTOR MANUALLY. USE HEAVY PROTECTIVE GLOVES AND MAKE SURE THAT YOU CANNOT SLIP. IF YOU DO NOT OBEY THESE INSTRUCTIONS, INJURY CAN OCCUR.

D. Inspection of booster blade.

NOTE: Any amount of erosion/flaking of abradable lining material on the outer shroud is permitted on booster vane stage 4.

(1) Inspect condition of booster blade stage 4 tip end and check for cracked leading edge, while rotating the fan rotor in a clockwise (CW) direction (aft looking forward) to complete procedure. For maximum serviceable limits (Ref. AMM TASK 72-21-00-290-001).
(2) When the inspection is completed, turn the switch off. Let the main light source blower on for a while to cool the lamp and the housing.

Subtask 72-21-00-480-053-A ** ON A/C NOT FOR ALL

E. Use 856A2501 WRENCH-VBV MANUAL CONTROL (856A2501G01) at 3:30, to manually close the VBV door.

Subtask 72-21-00-420-054-A ** ON A/C NOT FOR ALL

F. Lightly coat the 4 captive screws of the fan duct panel with graphite grease (Material No.CP2101) and install it at 3:30 between struts 4 and 5. TORQUE bolts to between 95 and 85 lbf.in (1.07 and 0.96 m.daN )

5. Close-up
Subtask 72-21-00-410-055-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close thrust reverser doors: (Ref. AMM TASK 78-36-00-410-040)
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 72-21-00-440-051-A ** ON A/C NOT FOR ALL

B. Make the thrust reverser serviceable (Ref. AMM TASK 78-30-00-081-041).

Subtask 72-21-00-410-057-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowl doors: (Ref. AMM TASK 71-13-00-410-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:38:08 UTC