W DOC AIRBUS | AMM A320F

Borescope Inspection of Stage 2-7 Low Pressure Turbine (LPT) Nozzle Segments [CFML]

TASK 72-00-00-290-819-A
Borescope Inspection of Stage 2-7 Low Pressure Turbine (LPT) Nozzle Segments

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.
ZONE: 210
ZONE: 400
1. Reason for the Job
This procedure gives criteria for the borescope inspection of stage 2-7 Low Pressure Turbine (LPT) nozzle segments.
NOTE: You can use equivalent alternatives for standard tools, equipment and consumable materials.
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
1
ACCESS PLATFORM 1M(3 FT)
No specific
AR
WARNING NOTICE(S)
 B. Work Zones and Access Panels
ZONE/ACCESS
ZONE DESCRIPTION
210
CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
400
POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 461AL, 462AR
 C. Referenced Information
REFERENCE
DESIGNATION
TASK 71-00-51-000-803-A
Removal of the Power Plant with 2D Bootstrap
TASK 71-00-51-400-803-A
Installation of the Power Plant with 2D Bootstrap
TASK 71-13-00-010-803-A
Opening of the Fan Cowl Doors
TASK 71-13-00-410-803-A
Closing of the Fan Cowl Doors
TASK 72-00-00-290-812-A
Engine Borescope Examination Preparation
TASK 78-30-00-040-809-A
Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-30-00-440-809-A
Reactivation of the Thrust Reverser System after Ground Maintenance
TASK 78-36-00-010-806-A
Opening of the Thrust Reverser Cowl Doors
TASK 78-36-00-410-806-A
Closing of the Thrust Reverser Cowl Doors
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
F Area Z
F Forward Deflector
F Visual Inspection of the Flow Path Area G - Coating Bubbles
F Borescope Inspection of the Low Pressure Turbine (LPT) Nozzle Segments
3. Job Set-up
Subtask 72-00-00-941-252-A
A. Safety Precautions
   (1) On the center pedestal, on ENG panel 115VU:
     (a) Make sure that the ENG/MODE selector switch is in the NORM position.
     (b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
     (c) Put a WARNING NOTICE(S) in position to tell persons not to operate:
  • The ENG/MODE selector switch
  • The ENG/MASTER 1(2) control switch.
   (2) On the ENG section of maintenance panel 50VU:
     (a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
     (b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).
Subtask 72-00-00-010-344-A
B. Get Access
   (1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
     (a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
     (b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
   (2) Put an ACCESS PLATFORM 1M(3 FT) in position.
Subtask 72-00-00-040-165-A
C. Deactivation of the Thrust Reverser System for Maintenance
WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.
   (1) Do the deactivation of the thrust reverser system for ground maintenance (Ref. AMM TASK 78-30-00-040-809).
Subtask 72-00-00-010-345-A
D. Get Access
   (1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-806):
     (a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
     (b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR
4. Procedure
Subtask 72-00-00-010-352-A
A. Removal of Borescope Plugs
   (1) Remove the borescope plugs (Ref. AMM TASK 72-00-00-290-812).
Subtask 72-00-00-480-088-A
B. Assemble the Borescope Inspection Tools
   (1) Assemble the borescope inspection tools (Ref. AMM TASK 72-00-00-290-812).
Subtask 72-00-00-290-146-A
C. Visual inspection of:
  • LPT stage 2 nozzle segments (1)
  • LPT stage 3 nozzle segments (2)
  • LPT stage 4 nozzle segments (3)
  • LPT stage 5 nozzle segments (4)
  • LPT stage 6 nozzle segments (5)
  • LPT stage 7 segments (6).
INSPECT/CHECK
MAXIMUM SERVICEABLE LIMITS
REMARKS
1.Visual inspection of all areas:
A.Evidence of burning missing metal
Stage 2, stage 3, stage 4, stage 5, stage 6 and stage 7 nozzle segments: Not serviceable.
Replace the engine (Ref. AMM TASK 71-00-51-000-803) and (Ref. AMM TASK 71-00-51-400-803).
B.Discoloration, heat scaling
Stage 2, stage 6 and stage 7 nozzle segments: Any amount if no distortion.

C.Metal deposit
Stage 2, stage 6 and stage 7 nozzle segments: Any amount with a maximum size/dimension of 0.047 in. (1.19 mm).
D.Peeling of particles
Stage 2, stage 6 and stage 7 nozzle segments: Any amount if the airfoils are not bowed or melted.

E.Porosity
Stage 2, stage 6 and stage 7 nozzle segments: Any amount.

F.Burns
Not serviceable.

G.Casting marks
Stage 2 nozzle segments: Any amount.

H.Corrosion
Stage 3, stage 4 and stage 5 nozzle segments: Any amount acceptable for 3200 cycles if no missing material.
NOTE: This continue-in-service limit is a repeat inspection.
2.Visual inspection of the Leading Edge (LE) (except fillets) in area Q:
See the sheets 2 to 7 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Cracks
  • Stage 2 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length if the cumulative length with a crack in the Trailing Edge (TE) section is not more than 0.16 in. (4.06 mm) on four airfoils maximum per segment
  • Stage 3 nozzle segments: No more than one crack per nozzle segment and maximum length up to 0.0299 in. (0.76 mm)
  • Stage 4 nozzle segments: Not serviceable
  • Stage 5 nozzle segments: No more than one radial crack per nozzle segment up to 0.0299 in. (0.76 mm) in length. Axial cracks not permitted
  • Stage 6 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length
  • Stage 7 nozzle segments: Any number if not more than 0.04 in. (1.02 mm) in length.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
B.Nicks, dents
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
C.Pitting, corrosion
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
D.Distortion
Stage 2, stage 6 and stage 7 nozzle segments: Not serviceable.
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, if more than the maximum serviceable limits.
3.Visual inspection of the LE fillets in area V:
See the sheets 2 to 7 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Cracks
  • Stage 2 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length if the cumulative length with a crack in the TE section is not more than 0.16 in. (4.06 mm) on four airfoils maximum per segment
  • Stage 3 nozzle segments: Not serviceable
  • Stage 4 nozzle segments: Not serviceable
  • Stage 5 nozzle segments: Not serviceable
  • Stage 6 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length
  • Stage 7 nozzle segments: Any number if not more than 0.04 in. (1.02 mm) in length.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
B.Nicks, dents
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
C.Pitting, corrosion
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
D.Distortion
Stage 2, stage 6 and stage 7 nozzle segments: Not serviceable.
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, if more than the maximum serviceable limits.
4.Visual inspection of the TE except fillets in area R:
See the sheets 2 to 7 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Cracks
  • Stage 2 nozzle segments: Any number if not more than 0.08 in. (2.03 mm) in length if the cumulative length with a crack in the LE section is not more than 0.16 in. (4.06 mm) in length on four airfoils maximum per segment
  • Stage 3 nozzle segments: On airfoil 1, axial cracks up to 0.078 in. (2.0 mm) in length are permitted, provided that all the cracks are located within one area with a height of no more than 0.039 in. (1.0 mm) and they are all located in area E or on any airfoil, no more than one axial crack per nozzle segment and maximum length up 0.0299 in. (0.76 mm). Radial cracks not permitted
  • Stage 4 nozzle segments: Not serviceable
  • Stage 5 nozzle segments: No more than one axial crack per nozzle segment and maximum length up to 0.0299 in. (0.76 mm). Radial cracks not permitted
  • Stage 6 nozzle segments: Any number if not more than 0.0492 in. (1.25 mm) in length
  • Stage 7 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
B.Nicks, dents
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
C.Pitting, corrosion
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
D.Distortion:
See the sheet 4 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
  • Stage 2 nozzle segments: Distortion acceptable if Dim P is not more than 0.04 in. (1.02 mm) for a Dim L of 0.35 in. (8.89 mm) minimum
  • Stage 6 nozzle segments: Distortion acceptable if Dim P is not more than 0.05 in. (1.27 mm). for a Dim L of 0.50 in. (12.70 mm) minimum
  • Stage 7 nozzle segments: Distortion acceptable if Dim P is not more than 0.05 in. (1.27 mm) for a Dim L of 0.50 in. (12.70 mm) minimum.
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, if more than the maximum serviceable limits.
E.Local deformation of TE
  • Stage 4 nozzle segments: Dimension L up to 0.196 in. (5 mm) and dimension P up to 0.019 in. (0.5 mm), provided minimum distance between two deformations is four times the length of the bigger deformation
  • Stage 5 nozzle segments: Dimension L up to 0.196 in. (5 mm) and dimension P up to 0.039 in. (1.0 mm), provided minimum distance between two deformations is four times the length of the bigger deformation.

F.Tears or axial cracks on TE, on airfoil 3 (except at fillet with inner platform)
  • Stage 5 nozzle segments: No more than one tear or crack per nozzle segment, up to 0.039 in. (1.0 mm) in length, provided it is located at more than 0.19 in. (5 mm) from outer platform and that the associated deformation has dimensions P up to 0.031 in. (0.8 mm) in depth, dimension L up to 10 percent of the TE length and the length/depth ratio is more than 10.

5.Visual inspection of the TE fillets in area U:
See the sheets 2 to 7 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Cracks
  • Stage 2 nozzle segments: Any number if not more than 0.08 in. (2.03 mm) in length if the cumulative length with a crack in the LE section is not more than 0.16 in. (4.06 mm) in length on four airfoils maximum per segment
  • Stage 3 nozzle segments: Not serviceable
  • Stage 4 nozzle segments: Not serviceable
  • Stage 5 nozzle segments: Not serviceable
  • Stage 6 nozzle segments: Any number if not more than 0.0492 in. (1.25 mm) in length
  • Stage 7 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length.
CONTINUE-IN-SERVICE LIMIT:
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
B.Nicks, dents
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
C.Pitting, corrosion
  • Stage 2 nozzle segments: Any number if not more than 0.012 in. (0.30 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.0138 in. (0.35 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.016 in. (0.41 mm) in depth.
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, with this condition:
Not more than one airfoil, maximum length up to 0.283 in. (7.19 mm).
D.Distortion:
See the sheet 4 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
  • Stage 2 nozzle segments: Distortion acceptable if Dim P is not more than 0.04 in. (1.02 mm) for a Dim L of 0.35 in. (8.89 mm) minimum
  • Stage 6 nozzle segments: Distortion acceptable if Dim P is not more than 0.05 in. (1.27 mm) for a Dim L of 0.50 in. (12.70 mm) minimum
  • Stage 7 nozzle segments: Distortion acceptable if Dim P is not more than 0.05 in. (1.27 mm) for a Dim L of 0.50 in. (12.70 mm) minimum.
Stage 2, stage 6 and stage 7 nozzle segments:
The continue-in-service limit is 100 cycles, if more than the maximum serviceable limits.
E.Local deformation of TE
  • Stage 4 nozzle segments: Not serviceable
  • Stage 5 nozzle segments: Not serviceable.

6.Visual inspection of the concave and the convex surfaces in area T:
See the sheets 2 to 7 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Cracks
  • Stage 2, stage 6 and stage 7 nozzle segments: Serviceable if cracks do not start from the concave and convex surfaces
  • Stage 3, stage 4 and stage 5 nozzle segments: except at fillets, no more than one crack per segment and within length of 0.059 in. (1.5 mm).

B.Nicks (except at fillets)
  • Stage 2 nozzle segments: Any number if not more than 0.0059 in. (0.15 mm) in depth
  • Stage 3, stage 4 and stage 5 nozzle segments: Any number up to 0.0031 in. (0.08 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.008 in. (0.20 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

C.Nicks at fillets
  • Stage 2 nozzle segments: Any number if not more than 0.0059 in. (0.15 mm) in depth
  • Stage 3 nozzle segments: Not serviceable
  • Stage 4 nozzle segments: Not serviceable
  • Stage 5 nozzle segments: Not serviceable
  • Stage 6 nozzle segments: Any number if not more than 0.008 in. (0.20 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

D.Dents (except at fillet)
  • Stage 2 nozzle segments: Any number if not more than 0.0059 in. (0.15 mm) in depth
  • Stage 3 nozzle segments: Any number up to 0.0098 in. (0.25 mm) in depth. Coating has to be ensured
  • Stage 4 and stage 5 nozzle segments: Any number up to 0.0098 in. (0.25 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.008 in. (0.20 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

E.Dents at fillets
  • Stage 2 nozzle segments: Any number if not more than 0.0059 in. (0.15 mm) in depth
  • Stage 3 nozzle segments: Any number up to 0.0098 in. (0.25 mm) in depth, provided that they are smoothly rounded with length/depth ratio equal to or higher than 10. Coating has to be ensured
  • Stage 4 and stage 5 nozzle segments: Any number up to 0.0098 in. (0.25 mm) in depth, provided that they are smoothly rounded with length/depth ratio equal to or higher than 10
  • Stage 6 nozzle segments: Any number if not more than 0.008 in. (0.20 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

F.Pitting, corrosion
  • Stage 2 nozzle segments: Any number if not more than 0.0059 in. (0.15 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.008 in. (0.20 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

G.Scratches
  • Stage 2 nozzle segments: Any number if not more than 0.0059 in. (0.15 mm) in depth
  • Stage 6 nozzle segments: Any number if not more than 0.008 in. (0.20 mm) in depth
  • Stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

7.Visual inspection of the flow path area J and S of the outer platforms:
See the sheets 9 and 11 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Axial cracks
  • Stage 2 nozzle segments: Serviceable if cracks do not start from the rear platform lips. Any number if not more than 0.2 in. (5.08 mm) in length
  • Stage 3 nozzle segments: No more than one crack per nozzle segment and maximum length up to 0.059 in. (1.5 mm)
  • Stage 4 nozzle segments: No more than one crack per nozzle segment and maximum length up to 0.039 in. (1.0 mm)
  • Stage 5 nozzle segments: No more than one crack per nozzle segment and maximum length up to 0.059 in. (1.5 mm)
  • Stage 6 nozzle segments: Any number if not more than 0.049 in. (1.24 mm) in length
  • Stage 7 nozzle segments: Any number if not more than 0.059 in. (1.50 mm) in length.

B.Circumferential cracks
  • Stage 2, stage 6 and stage 7 nozzle segments: Not serviceable
  • Stage 3, stage 4 and stage 5 nozzle segments: Not serviceable.
Replace the engine (Ref. AMM TASK 71-00-51-000-803) and (Ref. AMM TASK 71-00-51-400-803).
C.Nicks, dents
  • Stage 2, stage 6 and stage 7 nozzle segments: Any number if not more than 0.02 in. (0.51 mm) in depth
  • Stage 3, stage 4 and stage 5 nozzle segments: Nicks up to 0.0031 in. (0.08 mm) in depth. Dents up to 0.0098 in. (0.25 mm) in depth.

D.Pitting, corrosion
Stage 2, stage 6 and stage 7 nozzle segments: Any number if not more than 0.02 in. (0.51 mm) in depth.

8.Visual inspection of the flow path areas M, N, T and B of the outer platforms:
See the sheets 9 and 11 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Nicks, dents
  • Stage 2, stage 6 and stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

9.Visual inspection of the flow path areas H and P of the inner platforms:
See the sheets 8 and 10 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Circumferential cracks
  • Stage 2, stage 6 and stage 7 nozzle segments: Not serviceable
  • Stage 3, stage 4 and stage 5 nozzle segments: Not serviceable.
Replace the engine (Ref. AMM TASK 71-00-51-000-803) and (Ref. AMM TASK 71-00-51-400-803).
B.Radial cracks
  • Stage 2, stage 6 and stage 7 nozzle segments: Not serviceable
  • Stage 3, stage 4 and stage 5 nozzle segments: Not serviceable.
Replace the engine (Ref. AMM TASK 71-00-51-000-803) and (Ref. AMM TASK 71-00-51-400-803).
C.Nicks, dents
  • Stage 2, stage 6 and stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth
  • Stage 3, stage 4 and stage 5 nozzle segments: Nicks up to 0.0031 in. (0.08 mm) in depth. Dents up to 0.0098 in. (0.25 mm) in depth.

D.Pitting, corrosion
Stage 2, stage 6 and stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

E.Discoloration and heat scaling
Stage 2, stage 6 and stage 7 nozzle segments: Any amount if no distortion.

F.Evidence of burning, missing metal
Stage 2, stage 6 and stage 7 nozzle segments: Not serviceable.

G.Porosity
Stage 2, stage 6 and stage 7 nozzle segments: Any amount.

10.Visual inspection of the flow path areas K, L, Q and A of the inner platforms:
See the sheets 8 and 10 of the figure:
F Low Pressure Turbine (LPT) Stage 2 to 7 Nozzle Segments and LPT Stage 2 to 7 Borescope Segments
A.Nicks, dents
Stage 2, stage 6 and stage 7 nozzle segments: Any number if not more than 0.0098 in. (0.25 mm) in depth.

PRE SB 72-0332
11.Visual inspection of the area Z of the inner platform:
See the figure:
F Area Z
A.Cracks
  • Stage 6 nozzle segments: Not serviceable distortion
  • Stage 6 nozzle segments: Not serviceable.

B.Wear
Stage 6 nozzle segments: Any amount.
END OF PRE SB 72-0332
12.Visual inspection of the forward deflectors:
See the figure:
F Forward Deflector
A.Rub marks on inner band forward deflectors
Stage 5 nozzle segments: Any amount if not associated to deformation of the deflector.

B.Wear
Stage 3, stage 4 and stage 5 nozzle segments: Not serviceable.

13.Visual inspection of the flow path area G:
See the figure:
F Visual Inspection of the Flow Path Area G - Coating Bubbles
A.Coating bubbles
Stage 2 nozzle segments: Any amount.
Subtask 72-00-00-080-079-A
D. Removal of the Borescope
   (1) Remove the borescope (Ref. AMM TASK 72-00-00-290-812).
Subtask 72-00-00-410-304-A
E. Installation of the Borescope Plugs
CAUTION: WHEN YOU INSTALL THE BORESCOPE PLUGS, MAKE SURE THAT:
  • THE LOCKING FEATURE IS IN ONE OF THE TWO GROOVES ON THE BORESCOPE BOSS, AND
  • THERE IS NO GAP BETWEEN THE BORESCOPE BOSS AND PLUGS IN THE END.
IF YOU DO NOT OBEY THESE CONDITIONS, THE BORESCOPE PLUGS WILL NOT BE CORRECTLY INSTALLED.
   (1) Install the borescope plugs (Ref. AMM TASK 72-00-00-290-812):
F Borescope Inspection of the Low Pressure Turbine (LPT) Nozzle Segments
5. Close-up
Subtask 72-00-00-410-300-A
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 78-36-00-410-806):
     (a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
     (b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR
Subtask 72-00-00-440-157-A
B. Do the reactivation of the thrust reverser system after ground maintenance (Ref. AMM TASK 78-30-00-440-809).
Subtask 72-00-00-410-301-A
C. Close Access
   (1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
     (a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
     (b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
   (2) Remove the access platform(s).
   (3) Remove the WARNING NOTICE(S).
[Rev.10 from 2021] 2026.04.01 02:50:58 UTC
"Aviabrain" 2025