Inspection of the Stage 4 Blades [CFMB]

TASK 72-54-00-290-006-A
Inspection of the Stage 4 Blades

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	1	WRENCH 1/4 IN - RATCHET
No specific	Torque wrench: range to between 60 and 55 lbf.in (0.68 and 0.62 m.daN )
No specific	Torque wrench: range to between 110 and 95 lbf.in (1.24 and 1.07 m.daN )
856A1320	1	BORESCOPE-KIT
856A1322	1	BORESCOPE-LIGHT SOURCE SET

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP2101)	graphite grease
(Material No.CP2619)	Never Seez-Pure Nickel, Special
(Material No.CP8001)	lockwire 0.032 in. (0.8 mm) dia.
(Material No.CP8002)	lockwire 0.032 in. (0.8 mm) dia

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-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 72-54-00-210-004-A	Optional Visual Inspection of the Stage 4 Blades from the Rear of the Engine
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
Location of the Borescope Ports and Possible Borescope Access Via One Instrumentation Boss
Low-Pressure Turbine Borescope Inspection
Low-Pressure Turbine Blades and Nozzle Indications Description

3. Job Set-up
Subtask 72-54-00-941-057-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 72-54-00-010-068-A ** ON A/C NOT FOR ALL

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

Subtask 72-54-00-040-057-A ** ON A/C NOT FOR ALL

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

Subtask 72-54-00-010-076-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
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR

4. Procedure
Subtask 72-54-00-010-069-A ** ON A/C NOT FOR ALL

A. Remove the plugs which follow:

CAUTION: DO NOT REMOVE THE NUTS WHICH HOLD THE LPT BORESCOPE PLUG BOSS. TACK WELDS HOLD THE NUTS IN THEIR POSITIONS. THE REMOVAL OF THE NUTS CAN CAUSE DAMAGE TO THE STUDS.

(1) Let the temperature of parts decrease to ambient temperature.

PRE SB CFMI 72-0376

(2) Cut and remove the lockwire from the borescope plug S20. Remove the plug.

NOTE: The plug S20 is the aftmost borescope plug located at 5:00 o'clock on the LPT case (ALF).

END OF PRE SB CFMI 72-0376

POST SB CFMI 72-0376

(3) Remove the self locking borescope cap assembly S20.

NOTE: The plug S20 is the aftmost borescope cap assembly located at 5:00 o'clock on the LPT case (ALF).

NOTE: Specific procedure is not required to remove a self-locking borescope cap assembly. You can use a WRENCH 1/4 IN - RATCHET to loosen it.

END OF SB CFMI 72-0376

(4) Locate the instrumentation boss located at the 8:30 o'clock position (ALF) on the turbine frame.
(a) Remove the 2 bolts and nuts which attach a blanking plug to this turbine frame boss.
(b) Remove the blanking plug and its gasket.

NOTE: This gives you a borescope access to look at the trailing edge and tip shroud of the stage 4 LPT blades.

Subtask 72-54-00-480-055-A ** ON A/C NOT FOR ALL

B. Install the 856A1320 BORESCOPE-KIT (856A1320P04/P05) as follows:
(1) 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 the power supply to a grounded 110 VAC 60Hz power source.
(2) Connect light source cable to rigid borescope and to port on 856A1322 BORESCOPE-LIGHT SOURCE SET (856A1322P02/P03/P04/P07/P08).
(3) Turn light source on; insert borescope and position it as desired for inspection.

Subtask 72-54-00-290-055-A ** ON A/C NOT FOR ALL

C. The stage 4 LPT rotor blades are long span blades. To fully examine their airfoil surface, it is recommended to do these steps.
(1) Turn the fan rotor slowly and smoothly to examine the blades.
(2) Change the probe engagement depth to see the airfoils as the blades move in front of the probe.
(3) While you change the probe engagement depth, turn the probe (azimuth). This will let you have a maximum view for given turn speed of the rotor.

NOTE: The stage 4 blades have the longest span of the blade stages. So, as the full engagement of the probe is necessary, you may have to make 2, 3 or more turns of the LPT rotor to see all the blade areas.

(4) When you look at the leading edges of the blades, turn the rotor so that the concave side (or pressure face) of the blades comes toward the borescope.
(5) When you look at the trailing edges, turn the rotor in the opposite direction so that the convex side (suction face) comes toward the borescope.
(6) Do the inspection of the stage 4 blades for the damage as follows:

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Cracks	Not serviceable	See limit extensions (Ref. AMM TASK 72-00-00-200-025)
2.Nicks on concave or convex sides. Does not include area E.	Not more than 0.02 in. (0.5 mm) deep	See limit extensions (Ref. AMM TASK 72-00-00-200-025)
3.Dents on concave or convex sides. Does not include area E.	Not more than 0.01 in. (0.25 mm) deep	See limit extensions (Ref. AMM TASK 72-00-00-200-025)
4.Nicks and/or dents on leading or trailing edges. Does not include area E.	Not more than 0.02 in. (0.5 mm) deep	See limit extensions (Ref. AMM TASK 72-00-00-200-025)
5.Nicks and/or dents in area E.	Not more than 0.01 in. (0.25 mm) deep	See limit extensions (Ref. AMM TASK 72-00-00-200-025)
For CFM56-5B non/P engines
6.Tip shroud out of flush.	Not more than 0.0150 in. (0.38 mm)	See limit extensions (Ref. AMM TASK 72-00-00-200-025).
For CFM56-5B/P engines
7.Tip shroud out of flush.	Not more than 0.0354 in. (0.90 mm)	See limit extensions (Ref. AMM TASK 72-00-00-200-025) NOTE: If this out of flush condition is caused by over welding and if there is no evidence of unusual wear on the mating or hard faces all along the notch and the interlocks do fit one in another, this condition is serviceable. If different, refer to the criteria
8.Root platform out of flush.	Not more than 0.039 in. (1.0 mm)	See limit extensions (Ref. AMM TASK 72-00-00-200-025)
For ALL CFM56-5B engines
9.Shingled or unlatched tip shrouds.	Not serviceable	If you find the blade tip shrouds shingled or unlatched on different borescope inspections, it may be the sign of a wear of the hard-facing on the blade tip interlock surfaces. The 4th stage blades may be unshingled or relatched by hand (Ref. AMM TASK 72-54-00-210-004) See limit extensions (Ref. AMM TASK 72-00-00-200-025) See NOTE below.
10.Hard-facing wear.	Any quantity that does not cause a mismatch of the blade tip shroud aft face of more than 0.059 in. (1.50 mm). NOTE: 0.059 in. (1.5 mm) is corresponding to one cell width of the outer stationary air seal.	See limit extensions (Ref. AMM TASK 72-00-00-200-025). See NOTE below.
11.Blade airfoil pretwist that causes gaps such as interlocks do not touch each other.	Not serviceable.	See limit extensions (Ref. AMM TASK 72-00-00-200-025). See NOTE below. NOTE: If the aircraft maintenance schedule permits, it is recommended to do a visual inspection when you find these defects. Blades that are shingled or unlatched may be put back in their correct interlock positions, in following the special procedure (Ref. AMM TASK 72-54-00-210-004).
12.Distortion of leading edge caused by overtemperature.	Not serviceable
13.Deposit material peeling off airfoil.	Any amount, provided there is no evidence of bowing and/or melting

Subtask 72-54-00-080-055-A ** ON A/C NOT FOR ALL

D. Removal of Borescope
(1) When inspection is completed, turn lamp switch off, leave main light source blower on for a while to cool lamp and housing.
(2) Remove the borescope.

Subtask 72-54-00-410-068-A ** ON A/C NOT FOR ALL

E. Install the Borescope Plug S20 on the LPT Case

PRE SB CFMI 72-0376

(1) Apply graphite grease (Material No.CP2101) or CP2619Never Seez-Pure Nickel, Special, to the threads of the plug.

END OF PRE SB CFMI 72-0376

POST SB CFMI 72-0376

(2) Apply graphite grease (Material No.CP2101) to the threads of the self-locking borescope cap assembly.

END OF SB CFMI 72-0376

PRE SB CFMI 72-0376

(3) Install the plug on the LPT case. TORQUE to between 60 and 55 lbf.in (0.68 and 0.62 m.daN )

.

END OF PRE SB CFMI 72-0376

POST SB CFMI 72-0376

(4) Install the self-locking borescope cap assembly on the LPT case. TORQUE to between 60 and 55 lbf.in (0.68 and 0.62 m.daN )

NOTE: To achieve the correct installation of the self-locking borescope cap assembly, the slot of its ring must be positioned on the borescope boss lug at the final tightening.

END OF SB CFMI 72-0376

PRE SB CFMI 72-0376

(5) Safety the plug with CP8001lockwire 0.032 in. (0.8 mm) dia. or CP8002lockwire 0.032 in. (0.8 mm) dia.

END OF PRE SB CFMI 72-0376

Subtask 72-54-00-410-089-A ** ON A/C NOT FOR ALL

F. Install the blanking plug on the turbine frame instrumentation boss at 8:30 o'clock (ALF) as follows:
(1) Lubricate the threads of the 2 plug attachment bolts with graphite grease (Material No.CP2101) .
(2) Install the gasket on the blanking plug and engage the plug in the turbine frame boss.
(3) Install the 2 bolts and the 2 nuts (self-locking) to attach the plug to the boss.
(4) TORQUE the 2 nuts to between 110 and 95 lbf.in (1.24 and 1.07 m.daN )

5. Close-up
Subtask 72-54-00-410-069-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 cowl doors (Ref. AMM TASK 78-36-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 72-54-00-440-057-A ** ON A/C NOT FOR ALL

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

Subtask 72-54-00-410-077-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 12:59:35 UTC