Standard Borescope Inspection of Booster Rotor Blades, Stages 2, 3 and 4 through the Booster Inlet and Borescope Port SO [CFMI]

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

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)
856A1320	1	BORESCOPE-KIT
856A1322	1	BORESCOPE-LIGHT SOURCE SET

B. 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

C. 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 72-00-00-200-005-A	Over-Serviceable-Limit Extensions
TASK 72-21-00-290-002-A	Complementary (and optional) Borescope Inspection of the Booster Stage 4 Rotor Blade Tips Through One VBV Cavity.
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
Booster Borescope Port SO
Booster Rotor Blades Borescope Inspection
Booster Rotor Blades Damage Inspection (All 3 stages)

3. Job Set-up
Subtask 72-21-00-941-054-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 72-21-00-010-052-A ** ON A/C NOT FOR ALL

B. Open the 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 72-21-00-040-050-A ** ON A/C NOT FOR ALL

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

Subtask 72-21-00-010-055-A ** ON A/C NOT FOR ALL

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

4. Procedure
Subtask 72-21-00-290-052-A ** ON A/C NOT FOR ALL

A. Booster Inspection Methods.
(1) Inspection of booster rotor blades through borescope port SO and booster inlet.
(a) There is one borescope port (SO) located (approximately) at the 3.30 o'clock position at the periphery of the booster section and almost radially in line with the stage 3 of the booster stator. Through this port you can see the leading and trailing edges of the stage 3 and 4 rotor blades.

Booster Borescope Port SO ** ON A/C NOT FOR ALL

(b) Through, the booster inlet, you can get a borescope view of the booster rotor blades, stages 2 (LE and TE edges).
(c) To do the inspection of the booster stages 2, 3 and 4 rotor blades:
1 Use 856A1320 BORESCOPE-KIT (856A1320P04/P05) (field of view 60 deg., angle of vision 90 deg.) with a long right angle extension.
2 Use 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322P02/P03/P04/P07/P08)

NOTE: It is necessary to index and turn the fan rotor. You can turn the fan and booster rotor assembly by hand from the engine inlet.

Subtask 72-21-00-480-050-A ** ON A/C NOT FOR ALL

B. Installation of the borescope.

CAUTION: MAKE SURE THAT THE INPUT VOLTAGE OF THE BORESCOPE LIGHT SOURCE SET CORRESPONDS TO THAT OF THE POWER SUPPLY.

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

(1) Connect the 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322P02/P03/P04/P07/P08) to a grounded power supply.
(a) Connect the fiber light cable to the 856A1320 BORESCOPE-KIT (856A1320P04/P05) and to the port on the 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322P02/P03/P04/P07/P08).
(b) Turn the light source on. Engage the borescope and the long right-angle extension, and set it as necessary for inspection.

Subtask 72-21-00-290-050-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.

C. Borescope Inspection of the booster blades.

NOTE: Any amount of erosion/flaking of abradable lining material on the outer shroud is permitted on booster vane stages 3 & 4.

(1) Do the borescope inspection of the booster blades while you turn fan rotor clockwise (aft looking forward) to complete the procedure.

Booster Rotor Blades Damage Inspection (All 3 stages) ** ON A/C NOT FOR ALL

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Booster rotor blades (all stages) for: Booster Rotor Blades Damage Inspection (All 3 stages) ** ON A/C NOT FOR ALL NOTE: When the items which follow are not in the serviceable limits, refer to the over- serviceable limit extension if necessary. (Ref. AMM TASK 72-00-00-200-005).
A.Piece missing.	In area G, L/E and T/E tip corner missing, maximum number 20 blades serviceable up to 0.252 in. (6.4 mm) axial and radial
B.Cracks and tears	In area G, 0.787 in. (20 mm) from tip. Any number less than 0.256 in. (6.5 mm) radial less than 0.256 in. (6.5 mm) axial
C.Wear or local distortion of tip T/E and L/E	Any number 0.787 in. (20 mm) radial 0.492 in. (12.5 mm) axial.
D.Nicks, dents, scratches for area E	Any number, less than 0.019 in. (0.5 mm) in diameter protrusion acceptable, not thru

E.Nicks, dents, scratches for airfoil out of area "E" not L/E and T/E	Any number, less than 0.157 in. (4 mm) in diameter protrusion acceptable, not thru
F.Nicks, dents, scratches L/E and T/E out of area "E"	Maximum axial length less than 0.039 in. (1 mm).
G.Distorted L/E and T/E out of area "E"	Maximum axial length 0.197 in. (5 mm). Maximum radial length 0.59 in. (15 mm)
H.Deposits and erosion	Any amount

NOTE: A complementary (and optional) borescope inspection of the stage 4 rotor blade tips can be made through one of the VBV cavities. (Ref. AMM TASK 72-21-00-290-002)

Subtask 72-21-00-080-050-A ** ON A/C NOT FOR ALL

D. When inspection is complete, turn switch off. Leave main light source blower on for a while to cool lamp and housing.

5. Close-up
Subtask 72-21-00-410-052-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 72-21-00-440-050-A ** ON A/C NOT FOR ALL

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

Subtask 72-21-00-410-056-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 04:03:18 UTC