Borescope Inspection of the High Pressure Turbine (HPT) Vanes and Blade Outer Air Seal (BOAS) [PW11]

TASK 72-51-00-290-803-A
Borescope Inspection of the High Pressure Turbine (HPT) Vanes and Blade Outer Air Seal (BOAS)

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

WARNING: DO THE BORESCOPE INSPECTION IN AN AREA WHICH HAS PROTECTION FROM THE WEATHER. IF A BORESCOPE INSPECTION IS DONE IN WET CONDITIONS, USE SUFFICIENT PROTECTION TO PREVENT POSSIBLE ELECTRICAL SHOCK TO THE OPERATOR OR DAMAGE TO THE EQUIPMENT. AN ELECTRICAL SHOCK CAN KILL A PERSON OR CAUSE A BAD INJURY.

CAUTION: MAKE SURE THE TEMPERATURE IN THE ENGINE IS LESS THAN 150 DEG.F (65.6 DEG.C) BEFORE YOU INSTALL THE FLEXIBLE BORESCOPE IN THE ENGINE. IF THE ENGINE IS HOTTER THAN 150 DEG.F (65.6 DEG.C), THE FLEXIBLE BORESCOPE CAN MELT AND BE DAMAGED.

ZONE: 400

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE
No specific	1	BORESCOPE - FLEXIBLE
No specific	1	THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F
CTE8003	1	SYSTEM BOROSCOPE (VIDEO)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
TASK 71-13-00-010-802-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-802-A	Closing of the Fan Cowl Doors
TASK 72-00-00-000-804-A	Removal of the Borescope Plugs
TASK 72-00-00-400-804-A	Installation of the Borescope Plugs
TASK 78-30-00-040-805-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-30-00-440-805-A	Reactivation of the Thrust Reverser System after Ground Maintenance
TASK 78-36-00-010-802-A	Opening of the Thrust Reverser Cowl-Doors
TASK 78-36-00-410-802-A	Closing of the Thrust Reverser Cowl-Doors
TSM 71-00-00-810-853	Troubleshoot the Engine after a Flame Out - No/Low Fuel Flow event
TSM 71-00-00-810-871	Troubleshoot the Engine after a Flame Out - Fuel Flow Normal event
Borescope Inspection of The High Pressure Turbine (HPT)
Borescope Inspection of The High Pressure Turbine (HPT) Vanes and BOAS
Borescope Inspection of the HPT Vane and BOAS - Flame out

3. Job Set-up
Subtask 72-51-00-941-054-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).

Subtask 72-51-00-010-063-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR.
(2) Put the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE in position.

Subtask 72-51-00-040-054-A ** ON A/C NOT FOR ALL

C. Deactivation of the Thrust Reverser 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 maintenance (Ref. AMM TASK 78-30-00-040-805).

Subtask 72-51-00-010-064-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL, 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL, 462AR.

4. Procedure

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

Subtask 72-51-00-290-057-A ** ON A/C NOT FOR ALL

A. Borescope Inspection of the HPT Vanes and BOAS
(1) Operation intervals:
(a) See the Pratt and Whitney engine maintenance program for recommended intervals for each engine module.
(b) These inspection intervals can be adjusted based on the operator's experience and on the approval of the local regulatory agency.
(c) Operation at regular inspection interval limit:
1 If the damage of the parts is not more than the regular inspection limits, the engine can continue in service.
2 The parts will be examined again at the next regular inspection interval.
(d) Operation at reduced inspection interval limit:
1 If the parts are damaged to the reduced inspection interval limits, the engine can continue in service as noted in the inspection procedure. Parts must be examined again at the reduced inspection interval. Reduced interval is 1/2 the regular interval, unless specified differently. Contact Pratt & Whitney for further disposition.
(e) Operation at additional reduced inspection interval limit:
1 If the parts are damaged to the additional reduced inspection interval limits, the engine can continue in service as noted in the inspection procedure. Parts must be examined again at the reduced inspection interval. Reduced interval is 1/4 the regular interval, unless specified differently. Contact Pratt & Whitney for further disposition.
(f) Operation at more than the additional reduced inspection interval limit:
1 If the parts are damaged more than the additional reduced inspection interval limits, the engine cannot continue in service for more than five additional flight cycles unless otherwise specified in the inspection procedure for the parts.
2 The engine must be disassembled for repair or replacement of the damaged parts.
(2) If the engine has been run recently, check the temperature in the HPT with the THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F.
(a) It is recommended that you wait three to five hours after engine shutdown before you do a borescope inspection.
(b) As an option, you can dry-motor the engine with the starter to decrease the engine core temperature.
(3) Do the inspection with the CTE8003 SYSTEM BOROSCOPE (VIDEO).
(4) Remove the plug access port HPT-1 at the 4:30 o'clock position on the HPT case to view the HPT 2nd stage vanes and the 1st stage outer air seal segments.
(5) Remove the borescope plug access port TIC-1 at the 2:30 o'clock position on the HPT case to view HPT 2nd stage outer air seal segments (Ref. AMM TASK 72-00-00-000-804).
(a) The BORESCOPE - FLEXIBLE is required.
(6) Borescope inspection:

WARNING: BE CAREFUL TO EXAMINE THE POWER CABLE OF THE LIGHT SOURCE BEFORE YOU USE IT. DO NOT USE THE CABLE IF THE INSULATION HAS CUTS OR WORN OR BROKEN AREAS. INSULATION WITH THIS TYPE OF DAMAGE IS DANGEROUS BECAUSE OF POSSIBLE ELECTRICAL SHOCK TO THE OPERATOR.

CAUTION: INSTALL PROTECTION COVERS ON ALL THE OPENINGS IMMEDIATELY TO PREVENT DAMAGE TO THE ENGINE.

(a) Do the borescope inspection of the HPT 1st stage outer air seal segments and HPT 2nd stage vanes. Use access port HPT-1 for access. Refer to Tables 1 and 2.

Borescope Inspection of The High Pressure Turbine (HPT) ** ON A/C NOT FOR ALL

Borescope Inspection of The High Pressure Turbine (HPT) Vanes and BOAS ** ON A/C NOT FOR ALL

(7) Do the borescope inspection of the HPT 2nd stage outer air seal segments. Use access port HPT-1 and access port TIC-1 for access. Refer to Table 3.

Borescope Inspection of The High Pressure Turbine (HPT) Vanes and BOAS ** ON A/C NOT FOR ALL

EXAMINE	DAMAGE	DISPOSITION
General	Ceramic coating erosion or chipping is permitted in the limits that follow:
	There must be an undercoating (metal layer) on the damaged areas.	Permitted with a repetitive full wrap inspection interval of 2700 hours or 1350 cycles.
	All quantities without undercoating.	Not permitted. Remove the engine in five cycles or less.
Outer air seal segment gaspath surface for heavy rub	Transfer of blade material is permitted.	Permitted for regular inspection interval.
Outer air seal segment for axial cracks	Not permitted.	Not permitted. Remove the engine in five cycles or less.
Outer air seal segment for circumferential cracks	Not permitted.	Not permitted. Remove the engine in five cycles or less.
Erosion	0.005 in. (0.127 mm) maximum depth.	Permitted for regular inspection interval.
	All quantities more than 0.005 in. (0.127 mm) maximum depth.	Not permitted. Remove the engine in five cycles or less.
Outer air seal segment for edge burn back (missing material)	Not permitted.	Not permitted. Remove the engine in five cycles or less.
Outer air seal segment for burning into the cooling, cavity, spalling	Not permitted.	Not permitted. Remove the engine in five cycles or less.

Table - 1st Stage Outer Air Seal Segment Inspection (Nicks, Dents, Burning and Erosion)

EXAMINE	DAMAGE	DISPOSITION
Vane, platform and trailing edge cooling holes for:
Blocked condition	Fully blocked.	Contact Pratt & Whitney.
Airfoil and leading edge for:
Round bottom nicks and dents	All quantities to 0.010 in. (0.254 mm) depth. Damage less than 0.125 in. (3.175 mm) in diameter or length except at trailing edge. Damage must not expose base material.	Permitted for regular inspection interval.
	All quantities more than 0.010 in. (0.254 mm) depth and more than 0.125 in. (3.175 mm) in diameter or length.	Not permitted. Remove the engine in five cycles or less.
Trailing edge for:
Nicks and dents	Sharp edges, nicks or dents on each side not more than 0.010 in. (0.254 mm) are permitted. Damage must not block an individual cooling air slot by more than 50 per cent. Damage must not expose base material.	Permitted for regular inspection interval.
	All quantities more than 0.010 in. (0.254 mm) .	Not permitted. Remove the engine in five cycles or less.
Inner diameter and outer diameter platforms (gaspath side) for:
Round bottom nicks and dents	All quantities not more than 0.015 in. (0.381 mm) in depth. Damage must not show the base material.	Permitted for regular inspection interval.
	All quantities more than 0.015 in. (0.381 mm) in depth.	Not permitted. Remove the engine in five cycles or less.
Area A: Airfoil leading edge outer diameter and inner diameter (including fillet) for:
Cracks that you can see	Not permitted for more inspection intervals.
Area B: Airfoil leading edge (does not include fillet) for:
Cracks that you can see	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
Multiple cracks	Permitted for reduced inspection interval.	Regular (2700 hours or 1350 cycles).
Closed loop cracks	Not permitted.
Cracks that you can see that connect no more than two cooling holes	Permitted for reduced inspection interval.	Regular (2700 hours or 1350 cycles).
Cracks that you can see that connect three or more cooling holes	Permitted for additional reduced inspection intervals.	1/4 regular (675 hours or 337 cycles).
Missing material	Not permitted for more inspection intervals.
Areas C and F: Convex and concave surfaces of airfoil, includes fillet (does not include leading edge and trailing edge) for:
Axial cracks that go through to base metal between 0.650 in. (16.510 mm) and 0.690 in. (17.526 mm) in length	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
Closed loop cracks	Not permitted.
Axial cracks that go through to base metal between 0.690 in. (17.526 mm) and 0.700 in. (17.780 mm) in length	Permitted for reduced inspection interval.	1/2 regular (1350 hours or 675 cycles).
Axial cracks that go through to base metal between 0.700 in. (17.780 mm) and 0.710 in. (18.034 mm) in length	Permitted for additional reduced inspection interval.	1/4 regular (675 hours or 337 cycles).
Axial cracks that go through to base metal more than 0.710 in. (18.034 mm) in length	Remove the engine in 30 cycles or less.
Missing material that shows internal cooling circuit	Remove the engine in 30 cycles or less.
Area D: Airfoil trailing edge (includes fillet radius) for:
Axial cracks that go through to base metal, starting from the outer diameter trailing edge between 0.170 in. (4.318 mm) and 0.300 in. (7.620 mm) in length	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
Connecting cracks	Not permitted.
Axial crack through to base metal that starts from the outer diameter trailing edge between 0.300 in. (7.620 mm) and 0.450 in. (11.430 mm) in length	Permitted for reduced inspection interval.	1/2 regular (1350 or 675 cycles).
Axial cracks that go through to base metal that start from the outer diameter trailing edge between 0.450 in. (11.430 mm) and 0.520 in. (13.208 mm) in length	Permitted for additional reduced inspection interval.	1/4 regular (675 hours or 337 cycles).
Axial cracks that go through to base metal that start from the outer diameter trailing edge more than 0.520 in. (13.208 mm) in length	Remove the engine in 30 cycles or less.
Connected through to base metal cracks or missing material in the outer diameter trailing edge	Not permitted for more inspection intervals.
Regions A and B: Airfoil leading edge for:
All quantities of oxidation or erosion if it is not through the wall	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
NOTE: Through the wall means there is a hole in the wall.
All quantities of oxidation or erosion with a burn through if the internal wall has no signs of oxidation or erosion	Permitted for reduced inspection interval.	1/2 regular (1350 hours or 675 cycles).
NOTE: The term "internal wall" refers to the leading edge impingement wall between the internal space of the vane from the exterior.
All quantities of oxidation or erosion with a burn through where the internal wall does show signs of oxidation or erosion	Permitted for additional reduced inspection interval.	1/4 regular (675 hours or 337 cycles).
Oxidation or erosion that has caused a burn through of the internal wall	Remove the engine in ten cycles or less.
Region C: Concave surface of the airfoil for:
All quantities of surface oxidation or erosion with no depth	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles) .
All quantities of surface oxidation or erosion if it is not through the wall	Contact Pratt & Whitney.
Oxidation through the wall	Remove the engine in ten cycles or less.
Region D: Airfoil trailing edge for:
Burn back up to 0.125 in. (3.175 mm) axially from the trailing edge	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
Burn back more than 0.125 in. (3.175 mm) axially from the trailing edge	Contact Pratt & Whitney.
Region E: Inner platform for:
All quantities of oxidation or erosion depth less than 0.005 in. (0.127 mm)	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
All oxidation or erosion with depth more than 0.005 in. (0.127 mm)	Contact Pratt & Whitney.
Region F: Convex surface of airfoil for:
All quantities of surface oxidation or erosion with no depth	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
All quantities of surface oxidation or erosion if it is not through the wall	Permitted for reduced inspection interval.	1/2 regular (1350 hours or 675 cycles).
Oxidation through the wall	Remove the engine in ten cycles or less.
Region G: Outer platform for:
All quantities of oxidation or erosion with depth less than 0.005 in. (0.127 mm)	Permitted for regular inspection interval.	Regular (2700 hours or 1350 cycles).
All oxidation or erosion with depth more than 0.005 in. (0.127 mm)	Contact Pratt & Whitney.
Airfoil surface (both sides, includes leading edge)	Three areas of coat loss up to 0.400 in.2 (258.064 mm2) total, each side.	Permitted for regular inspection interval.
	Coat loss in an area 0.050 in. (1.270 mm) around cooling air holes.	Permitted for regular inspection interval.
	All quantities more than three areas of coat up to 0.400 in.2 (258.064 mm2).	Contact Pratt & Whitney.
Trailing edge (convex side)	All quantities of coat loss 0.100 in. (2.540 mm) from trailing edge.	Permitted for regular inspection interval.
	All quantities of coat loss more than 0.100 in. (2.540 mm) from trailing edge.	Contact Pratt & Whitney.
Trailing edge (concave side)	All quantities of coat loss 0.250 in. (6.350 mm) from trailing edge.	Permitted for regular inspection interval.
	All quantities of coat loss more than 0.250 in. (6.350 mm) from trailing edge.	Contact Pratt & Whitney.
Vane platforms for:	All quantities of coat chipping or erosion.	Permitted for regular inspection interval.
	Coat missing from an area 0.050 in. (1.270 mm) around platform cooling air hole.	Permitted for regular inspection interval.
	All quantities of coat loss more than 0.050 in. (1.270 mm) around platform cooling air holes.	Contact Pratt & Whitney.
Seals	Three seals can come out from the vane platform, at a location. No limit to the length of the seal that can be seen.	Permitted for regular inspection interval.
	More than three locations.	Not permitted. Remove the engine in five cycles or less.

Table - 2nd Stage Turbine Vane Inspection (Cooling Air Holes, Nicks, Dents, Cracks, Burning and Erosion)

EXAMINE	DAMAGE	DISPOSITION
Outer air seal segment gaspath surface for:
Heavy rub	Transfer of blade material is permitted.	Permitted for regular inspection interval.
Outer air seal segment for:
Axial cracks	Not permitted.	Not permitted. Remove the engine in five cycles or less.
Circumferential cracks	Not permitted.	Not permitted. Remove the engine in five cycles or less.
Edge burn back (missing material)	Not permitted.	Not permitted. Remove the engine in five cycles or less.
Burning into the cooling cavity	Not permitted.	Not permitted. Remove the engine in five cycles or less.
For flame out only: Raised material that is more than the length of the 2nd stage blade tip cooling holes TSM 71-00-00-810-853 and TSM 71-00-00-810-871. Borescope Inspection of the HPT Vane and BOAS - Flame out ** ON A/C NOT FOR ALL	Not permitted.	Not permitted. Remove the engine in five cycles.

Table - 2nd Stage Turbine Outer Air Seal Segment Inspection (Cracks, Missing Material, Burning and Erosion)

(8) Install the access port HPT-1 and access port TIC-1 borescope plugs (Ref. AMM TASK 72-00-00-400-804).

5. Close-up
Subtask 72-51-00-410-061-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 78-36-00-410-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL, 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL, 462AR.

Subtask 72-51-00-440-054-A ** ON A/C NOT FOR ALL

B. Do the reactivation of the thrust reverser system after maintenance (Ref. AMM TASK 78-30-00-440-805).

Subtask 72-51-00-410-062-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 13:02:11 UTC