Borescope Inspection of the High Pressure Turbine Rotor Blade (from the front) [CFMB]

TASK 72-52-00-290-004-A
Borescope Inspection of the High Pressure Turbine Rotor Blade (from the front)

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

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

1. Reason for the Job
This TASK is applicable for NON /P and NON /3 engines.
Inspection of the high pressure turbine (HPT) blades from the front is limited to the areas that can be seen with a flexible borescope installed at the spark igniter ports (S10 and S11).

NOTE: There are 80 HPT blades installed in the rotor.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	BAR LENGTH 60 CM (2 FT) BREAKER
No specific	AR	CAP - PROTECTION
No specific	AR	SPEED BRACE 3/4 IN - SQUARE DRIVE
No specific	AR	WARNING NOTICE(S)
856A1310	1	KIT, BORESCOPE GUIDE - HP TURBINE
856A1321	1	FIBERSCOPE SET
856A1322	1	BORESCOPE-LIGHT SOURCE SET
856A1323	1	MONITOR, RESOLUTION BORESCOPE
856A1488	1	MOTOR, DRIVE - CORE ENGINE ROTATION

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-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 72-00-00-200-025-A	Over-Serviceable-Limit Extensions
TASK 72-00-00-200-025-A-01	Over-Serviceable-Limit Extensions
TASK 72-42-00-290-005-A	Inspection of the Combustion Chamber and HPT Nozzle Following a Birdstrike/FOD (SAC engine)
TASK 72-42-00-290-005-A-01	Inspection of the Combustion Chamber and HPT Nozzle Following a Birdstrike/FOD (DAC engine)
TASK 72-63-00-000-002-A	Removal of the Handcranking Drive Cover
TASK 72-63-00-400-002-A	Installation of the Handcranking Drive Cover
TASK 74-21-30-000-002-A	Removal of the Spark Igniter
TASK 74-21-30-400-002-A	Installation of the Spark Igniter
TASK 78-30-00-081-041-B	Make the Thrust Reverser Serviceable after Maintenance
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
TASK 78-36-00-410-040-B	Closing of the Thrust Reverser Doors
TASK 80-11-10-000-002-A	Removal of the Pneumatic Starter
TASK 80-11-10-400-002-A	Installation of the Pneumatic Starter
NTM 720000
Inspection of the HPT Blade (Only applicable for SAC Engines)
Rub Wear Notches on the Blade Tip and Cracks (Only Applicable NON /P Engines)
High-Pressure Turbine Blade Inspection Areas (Only Applicable NON /P Engines)
High-Pressure Turbine Blade (Only Applicable NON /P Engines)
Core Rotation Drive Motor Installation
Inspection of the HPT Blade (Only applicable for DAC Engines)

3. Job Set-up
Subtask 72-52-00-941-052-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 72-52-00-010-054-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowls doors: (Ref. AMM TASK 71-13-00-010-040)
(2) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(3) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
(4) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.

Subtask 72-52-00-040-052-A ** ON A/C NOT FOR ALL

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

Subtask 72-52-00-010-055-A ** ON A/C NOT FOR ALL

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

4. Procedure
Subtask 72-52-00-290-052-A ** ON A/C NOT FOR ALL

A. Prepare for inspection:
(1) Use the 856A1323 MONITOR, RESOLUTION BORESCOPE (856A1323G01) to make sure the borescope and the light source are serviceable. See the Non-Destructive Test Manual for this procedure NTM 720000.
(2) Install the tools to turn the core engine.

NOTE: The core engine may be turned using a breaker bar (see step (a)) or with a drive motor (see step (b)).

(a) To turn the core manually with a breaker bar, do the steps that follow:
1 Remove the handcranking drive cover from the core rotation pad on the left side of the accessory gearbox (AGB), opposite the starter (Ref. AMM TASK 72-63-00-000-002).
2 Install a SPEED BRACE 3/4 IN - SQUARE DRIVE with a BAR LENGTH 60 CM (2 FT) BREAKER into the handcranking drive pad. When you do the borescope inspection, turn the core engine clockwise (CW, aft looking forward).

NOTE: To turn the core engine CW, the handcranking drive must be turned counterclockwise (CCW).

(b) To turn the core with a drive motor, do the steps that follow:
1 Remove the starter (Ref. AMM TASK 80-11-10-000-002).
2 Install the 856A1488 MOTOR, DRIVE - CORE ENGINE ROTATION (856A1488 P01 or P02) into the accessory gearbox (AGB) starter drive pad. Align the drive shaft of the drive motor with the starter drive pad drive shaft and engage the splines.

NOTE: The tool must be installed in the horizontal position with the air hoses to the rear.

3 Turn the tool until the captive bolts align with the gearbox bolt holes.
4 Tighten the two captive bolts by hand.
5 Install the clamp to secure the drive motor.
6 Attach the foot or hand control air hoses to the quick disconnects on the tool.
7 Connect the air supply to the drive motor. The air supply must be capable of 100 psi (6.9 bar). The air supply must be lubricated and filtered at 6 SCFM (170 L/minute).
(3) Remove either one of the spark igniters (Ref. AMM TASK 74-21-30-000-002).
(4) Install the CAP - PROTECTION on the lead and the spark igniter.
(5) Put the 856A1310 KIT, BORESCOPE GUIDE - HP TURBINE (856A1310G01) over the straightening rod.
(6) Push the plastic guide tube and straightening rod into the combustion chamber through the spark igniter port (S10 or S11) as far as it will go.
(7) Turn the pointed tab on the plastic guide tube to the rear of the engine and remove the straightening rod from the plastic guide tube.
(8) Installation of the borescope:

CAUTION: FOLLOW THE INSTRUCTIONS CAREFULLY FOR INSERTING OR REMOVING THE FLEXIBLE BORESCOPE. DOING THE PROCEDURE INCORRECTLY WILL DAMAGE THE TIP CONTROL FUNCTION.

(a) Connect the fiber light cable to the 856A1321 FIBERSCOPE SET (856A1321 P01 or P03) to the 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322 P03, P04 or P07).
(b) Align the borescope lens with one of the plastic tabs on the guide tube and install it into the tube. Make sure that the borescope tip is not moved up or down when putting it into the plastic guide tube.
(c) Push the borescope through the plastic guide tube until the tip comes out of the end of the tube.
(d) Push the tip of the borescope between the nozzle vanes by using the tip deflection control.
(e) Turn on the light source of the 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322 P03 or P04).
(f) Adjust the borescope equipment to get maximum clarity of view.
(9) Turn the HPT rotor CW (aft looking forward). Stop the rotor at each blade to make sure all of the defects can be seen.

NOTE: To turn the HPT rotor CW, the rotation pad drive must be turned CCW.

(10) Inspect the HPT blades (from the front) and use the limits that follow:

NOTE: It is not easy to visually tell when cooling holes are plugged. Cooling holes which are apparently plugged are permitted if any cracking, erosion or burning is within serviceable limits.

NOTE: Crack indications which are not completely identified may be sprayed with solvent (CP2011) or an equivalent substitute to remove light engine deposits.

NOTE: When a HPT blade has impact damage, you must do a 360 degree combustor borescope inspection to look for combustor distress (Ref. AMM TASK 72-42-00-290-005).

NOTE: For purposes of estimating the size of any distress, the radial spacing of the trailing edge slots is approximately 0.1 in. (2.55 mm).

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Leading edge for:
A.Axial and radial cracks in area A.	Any number 0.05 in. (1.27 mm) long if they do not connect more than 2 holes.	See limit extensions (Ref. AMM TASK 72-00-00-200-025).
B.Axial and radial cracks in areas B and C, including root radius not intersecting nose or gill holes.	Not serviceable.
C.Nicks and dents in area A.	Any amount.
D.Nicks and dents in area B.	Any amount.
E.Nicks and dents in area C, including root radius.	3 permitted, 0.05 in. (1.27 mm) long. Nicks and dents must be separated by 0.125 in. (3.17 mm) minimum.
F.Axial nose or gill hole cracks, areas B and C.	Not serviceable.	See limit extensions (Ref. AMM TASK 72-00-00-200-025).
G.Radial nose or gill hole cracks, areas B and C.	None allowed in area C, one permitted, 0.03 in. (0.76 mm) long in area B.	See limit extensions (Ref. AMM TASK 72-00-00-200-025).
H.Dirt or environmental build-up.	Any amount.
J.Missing thermal barrier coating.	Any amount.
K.Through wall hole in area A and area B.	Permitted with these conditions: a) Cavity 2 is not exposed. b) Not more than 2 blades have a through wall hole. Do the inspection again after each 100 cycles.	Refer to limit extensions (Ref. AMM TASK 72-00-00-200-025).
L.Through wall hole in area C	Permitted with these conditions: a) Engines covered by SB CFM 72-0644 or CFM 72-0849. b) Hole size less than 0.070 in. (1.8 mm) diameter. Do the inspection again after each 100 cycles.	Refer to limit extensions (Ref. AMM TASK 72-00-00-200-025).
M.Discoloration and oxidation.	Any amount if you do the inspection again after each 400 cycles.
2.Blade tip for:
NOTE: There are 4 notched blades (90 degrees apart) in the HPT rotor to show the amount of blade tip rubbing. If the notches can or cannot be seen, the condition is serviceable.
A.Radial cracks on concave side.	Any number permitted 0.7 in. (17.78 mm) max radial length.	See limit extensions (Ref. AMM TASK 72-00-00-200-025).
B.Bent, curled or missing material.	Any amount within 0.2 in. (5.08 mm) of tip.
C.Missing thermal barrier coating.	Any amount.
3.Concave and convex surfaces for:
A.Nicks or dents, area A.	Any number 0.25 in. (6.35 mm) long.
B.Nicks or dents, area B.	Any number, 0.1 in. (2.54 mm) long.
C.Nicks or dents, area C.	3 permitted, 0.05 in. (1.27 mm) long. Nicks and dents must be separated by 0.125 in. (3.17 mm) minimum.
D.Cracks, other areas.	Not serviceable.
E.Missing thermal barrier coating.	Any amount.

(11) When the inspection is completed, turn off the 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322 P03, P04 or P07) and remove the 856A1321 FIBERSCOPE SET (856A1321 P01 or P03) and guide tube.
(12) Install the spark igniter (Ref. AMM TASK 74-21-30-400-002).
(13) Remove the tools used to rotate the core as follows:

NOTE: If the breaker bar is installed see steps (a) and (b). If the drive motor is installed see steps (c) and (d).

(a) Remove the 0.75 in. (19.05 mm) square drive socket and 2 ft. (0.6 mm) breaker bar from the core rotation drive pad.
(b) Install the handcranking drive pad cover (Ref. AMM TASK 72-63-00-400-002).
(c) Remove the drive motor from the starter pad of the AGB.
(d) Install the starter (Ref. AMM TASK 80-11-10-400-002).

5. Close-up
Subtask 72-52-00-410-054-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 the thrust reverser doors (Ref. AMM TASK 78-36-00-410-040).
(3) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(4) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 72-52-00-440-052-A ** ON A/C NOT FOR ALL

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

Subtask 72-52-00-410-055-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowls (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 access platform(s).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:42:57 UTC