DOC AIRBUS | AMM A320FBorescope Inspection of Combustion Chamber and HPT Nozzle Guide Vanes [PW11]
TASK 72-41-00-290-802-A
Borescope Inspection of Combustion Chamber and HPT Nozzle Guide Vanes
Refer to the MPD TASK: 724000-W2
BORESCOPE INSPECTION OF COMBUSTION CHAMBER AND HPT NOZZLE GUIDE VANES.
Use this procedure to inspect the diffuser case assembly area for burning, burn-back, burn-through, chips and cracks, nicks and dents, erosion and shell distress damage.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 72-41-00-941-054-A ** ON A/C NOT FOR ALL
Subtask 72-41-00-290-052-A ** ON A/C NOT FOR ALL
Subtask 72-41-00-860-050-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 13:02:00 UTC
Borescope Inspection of Combustion Chamber and HPT Nozzle Guide Vanes
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AND THE ADJACENT COMPONENTS AFTER ENGINE SHUTDOWN. THE ENGINE, THE ENGINE OIL AND THE ADJACENT COMPONENTS CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
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 JobRefer to the MPD TASK: 724000-W2
BORESCOPE INSPECTION OF COMBUSTION CHAMBER AND HPT NOZZLE GUIDE VANES.
Use this procedure to inspect the diffuser case assembly area for burning, burn-back, burn-through, chips and cracks, nicks and dents, erosion and shell distress damage.
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 | 1 | BORESCOPE - FLEXIBLE |
| No specific | 1 | THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F |
| CTE8003 | 1 | SYSTEM BOROSCOPE (VIDEO) |
| 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 | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 71-00-00-860-817-A | Motor the Engine (Dry Method) |
| 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 72-51-00-290-802-A | Borescope Inspection of the 1st and 2nd Stage Turbine Blades |
| TASK 72-53-00-200-801-A | Borescope Inspection of the Low Pressure Turbine (LPT) Assembly |
| TASK 74-21-01-000-801-A | Removal of the Igniter Plug |
| TASK 74-21-01-400-801-A | Installation of the Igniter Plug |
| 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 |
Subtask 72-41-00-941-054-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 72-41-00-010-058-A ** ON A/C NOT FOR ALL (1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).
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) in position.
Subtask 72-41-00-040-054-A ** ON A/C NOT FOR ALL (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) in position.
C. Deactivation of the Thrust Reverser for Maintenance
Subtask 72-41-00-010-059-A ** ON A/C NOT FOR ALL 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). 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(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.
Subtask 72-41-00-290-052-A ** ON A/C NOT FOR ALL
A. Borescope Inspection of the Diffuser Case Assembly
(1) Borescope inspection interval information:
(a) Refer to the Pratt & Whitney engine maintenance plan for the recommended intervals for each engine module.
(b) These inspection intervals can be adjusted based on the operator experience and approval of the local regulatory agency.
(c) Operation at the regular inspection interval limits:
1 If the part damage is in the regular inspection interval criteria, the engine can continue in service.
2 The parts will be examined again at the next regular inspection interval.
(d) Operation at the reduced inspection limits:
1 If the parts are damaged to the reduced inspection interval limits, the engine can continue in service as noted in the inspection procedure. The parts must be examined again at the reduced inspection interval. The reduced interval is the half of the regular interval, unless specified differently. Contact Pratt & Whitney for further instructions.
(e) Operation at the additional reduced inspection interval limits:
1 If the parts are damaged in the additional reduced inspection interval limits, the engine can continue in service as specified in the inspection procedure. The parts must be examined again at the additional reduced inspection interval. The additional reduced interval is the quarter of the regular interval, unless specified differently. Contact Pratt & Whitney for more instructions.
(f) Operation at more than the additional reduced inspection limits:
1 If the parts are damaged more than the additional reduced inspection interval limits, the engine cannot continue in service for more than 30 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) Remove borescope plug access-port DIFF-1 to get access to the combustion chamber for the borescope inspection (Ref. AMM TASK 72-00-00-000-804).
(a) As an option, an igniter plug at the three and four o'clock locations can be removed for better access (Ref. AMM TASK 74-21-01-000-801).
(3) If the engine has been run recently, do a check of the temperature in the High Pressure Compressor (HPC) with the THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F.
(a) It is recommended that you wait for three to five hours after the 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 (Ref. AMM TASK 71-00-00-860-817).
(4) Do the inspection:
(6) Do the borescope inspection of the combustion chamber assembly and the HPT 1st stage vane assembly as required to identify damage. Use access port DIFF-1 on the diffuser case to do the inspection. Alternate borescope use is through the igniter bosses. See Tables 601 and 602.
The Combustion Chamber Area - (Definition of Distress in and Around Combustion Holes) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Burnback or Burnthrough) ** ON A/C NOT FOR ALL
(b) Examine the outer combustion chamber bulkhead area and the fuel nozzles for the overall combustor feature description, outer segment and shell distress descriptions, details on the crack definition, stud location and combustion hole distress descriptions. See Table 1 and the figures:
The Combustion Chamber Area - (Definition of Distress in and Around Combustion Holes) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (Outer Chamber Igniter Guides and Swirler Assembly Faces) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Burnback or Burnthrough) ** ON A/C NOT FOR ALL
(c) Examine the combustion chamber bulkhead area and fuel nozzles for the bulkhead, outer segment, shell/bulkhead distress descriptions and crack definition and stud location. See Table 1 and the figures:
The Combustion Chamber Area - (Definition of Distress in and Around Combustion Holes) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Burnback or Burnthrough) ** ON A/C NOT FOR ALL
(d) Examine the HPT 1st stage turbine vane assembly. See Table 2 and the figures:
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Cracking, Erosion and Missing Coat) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane OD Platform for Cracking) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane ID Platform for Cracking) ** ON A/C NOT FOR ALL
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly For Cracking) ** ON A/C NOT FOR ALL
(e) Determine the crack lengths as follows:
The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly For Cracking) ** ON A/C NOT FOR ALL
2 For the intersecting cracks, measure the longest distance of each crack from the start to the intersection of the cracks.
3 Add the longest distance of each crack to get the total length of the intersecting cracks.
(8) If necessary, install the igniter plug(s) at the three and four o'clock locations (Ref. AMM TASK 74-21-01-400-801).
(9) Examine the assembly for foreign objects, damage and correct assembly.
5. Close-up(1) Borescope inspection interval information:
(a) Refer to the Pratt & Whitney engine maintenance plan for the recommended intervals for each engine module.
(b) These inspection intervals can be adjusted based on the operator experience and approval of the local regulatory agency.
(c) Operation at the regular inspection interval limits:
1 If the part damage is in the regular inspection interval criteria, the engine can continue in service.
2 The parts will be examined again at the next regular inspection interval.
(d) Operation at the reduced inspection limits:
1 If the parts are damaged to the reduced inspection interval limits, the engine can continue in service as noted in the inspection procedure. The parts must be examined again at the reduced inspection interval. The reduced interval is the half of the regular interval, unless specified differently. Contact Pratt & Whitney for further instructions.
(e) Operation at the additional reduced inspection interval limits:
1 If the parts are damaged in the additional reduced inspection interval limits, the engine can continue in service as specified in the inspection procedure. The parts must be examined again at the additional reduced inspection interval. The additional reduced interval is the quarter of the regular interval, unless specified differently. Contact Pratt & Whitney for more instructions.
(f) Operation at more than the additional reduced inspection limits:
1 If the parts are damaged more than the additional reduced inspection interval limits, the engine cannot continue in service for more than 30 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) Remove borescope plug access-port DIFF-1 to get access to the combustion chamber for the borescope inspection (Ref. AMM TASK 72-00-00-000-804).
(a) As an option, an igniter plug at the three and four o'clock locations can be removed for better access (Ref. AMM TASK 74-21-01-000-801).
(3) If the engine has been run recently, do a check of the temperature in the High Pressure Compressor (HPC) with the THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F.
(a) It is recommended that you wait for three to five hours after the 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 (Ref. AMM TASK 71-00-00-860-817).
(4) Do the 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.
(a) Do the inspection with the CTE8003 SYSTEM BOROSCOPE (VIDEO).NOTE: As an option, if a larger view area is necessary, it is permitted to use the BORESCOPE - FLEXIBLE for all the steps.
(5) Insert the borescope probe through access port DIFF-1 for the examination of the combustion chamber assembly and the High Pressure Turbine (HPT) 1st stage vanes. (6) Do the borescope inspection of the combustion chamber assembly and the HPT 1st stage vane assembly as required to identify damage. Use access port DIFF-1 on the diffuser case to do the inspection. Alternate borescope use is through the igniter bosses. See Tables 601 and 602.
NOTE: Missing thermal barrier coat can cause increased bulkhead panel and liner segment deterioration.
(a) Examine the inner combustion chamber assembly for the overall combustor feature description, inner segment and shell descriptions, details on crack definition, stud location and combustion hole distress descriptions. See Table 601 and the figures: The Combustion Chamber Area - (Definition of Distress in and Around Combustion Holes) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Burnback or Burnthrough) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (Definition of Distress in and Around Combustion Holes) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (Outer Chamber Igniter Guides and Swirler Assembly Faces) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Burnback or Burnthrough) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (Definition of Distress in and Around Combustion Holes) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Burnback or Burnthrough) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly for Cracking, Erosion and Missing Coat) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane OD Platform for Cracking) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane ID Platform for Cracking) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly For Cracking) ** ON A/C NOT FOR ALL The Combustion Chamber Area - (HPT 1st Stage Turbine Vane Assembly For Cracking) ** ON A/C NOT FOR ALL NOTE: Crack refers to a crack in the base metal. Hairline cracks adjacent to the base metal cracks that do not have missing coat are cracks in the coat only because they do not go through the base metal.
1 For the continuous crack, measure the longest distance from the start to the end of the crack.2 For the intersecting cracks, measure the longest distance of each crack from the start to the intersection of the cracks.
3 Add the longest distance of each crack to get the total length of the intersecting cracks.
| EXAMINE | DAMAGE | DISPOSITION |
|---|---|---|
| The inner and outer liner segments, fuel nozzle and bulkhead segments for discoloration or carbon accumulation. | All quantities. | Permitted for regular inspection interval. |
| The front and rear inner and outer liner segments and bulkhead segments for missing thermal barrier coat. | All quantities. | Permitted for regular inspection interval. |
| The front inner and outer liner segments for cracks (includes the igniter segment) (with or without burning). | All quantities of cracks less than 0.250 in. (6.350 mm) in length maximum. | Permitted for inspection interval of 1500 hours. |
| | Cracks less than half the liner segment in axial length, separated by more than 2.500 in. (63.500 mm) and more than 0.650 in. (16.510 mm) from the circumferential edge. | Permitted for inspection interval of 1500 hours. |
| | One or more crack(s) that is (are) not more than the liner segment in axial length, separated from other cracks by more than 2.500 in. (63.500 mm) and more than 0.650 in. (16.510 mm) from the circumferential edge. | Permitted for inspection interval of 750 hours. |
| | Cracks less than half the liner segment axial length with less than 2.500 in. (63.500 mm) between cracks and more than 0.650 in. (16.510 mm) from the circumferential edge. | Permitted for inspection interval of 750 hours. |
| | Cracks less than two thirds of the liner segment axial length with less than 2.500 in. (63.500 mm) between cracks and more than 0.650 in. (16.510 mm) from the circumferential edge. | Permitted for inspection interval of 375 hours. |
| | All cracks that can connect and cause material liberation less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All cracks that cause less than 50 percent separation of one stud from the segment. | Permitted for inspection interval of 150 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All cracks that can connect and cause material liberation more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All cracks that cause more than 50 percent separation of one stud from the segment. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The rear inner and outer liner segments for cracks (with or without burning). | All quantities of cracks less than 0.250 in. (6.350 mm) in length maximum. | Permitted for inspection interval of 1500 hours. |
| | Any single crack that connects a combustion hole to the liner segment edge. | Permitted for inspection interval of 1500 hours. |
| | Cracks with length less than 1.000 in. (25.400 mm), separated by more than 1.500 in. (38.100 mm) and more than 0.750 in. (19.050 mm) from the circumferential edge. | Permitted for inspection interval of 1500 hours. |
| | Cracks that connect a combustion hole and the liner segment edge, provided the following conditions are met: A. Axial cracks are more than 0.750 in. (19.050 mm) from the circumferential edge. B. Cracks are separated by the combustion hole that has no cracks. | Permitted for inspection interval of 750 hours. |
| | Cracks with length less than 2.000 in. (50.800 mm), separated by less than 1.500 in. (38.100 mm) and more than 0.750 in. (19.050 mm) from the circumferential edge. | Permitted for inspection interval of 750 hours. |
| | Cracks with length more than 2.000 in. (50.800 mm), with less than 1.500 in. (38.100 mm) between cracks and more than 0.750 in. (19.050 mm) from the circumferential edge. | Permitted for inspection interval of 375 hours. |
| | All quantities of cracks that can connect and cause material liberation less than 0.400 in.2 (258.064 mm2). | Permitted for inspection interval of 375 hours. If it looks like the liner segment material is liberated, do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All cracks that cause less than 50 percent separation of one stud from the segment. | Permitted for inspection interval of 150 hours. |
| | All cracks that can connect and cause material liberation more than 0.400 in.2 (258.064 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All cracks that cause more than 50 percent separation of one stud from the segment. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The bulkhead segments for cracks (with or without burning). | All cracks with length less than a quarter of the distance between the segment and the swirler hole. | Permitted for inspection interval of 1500 hours. |
| | No more than one crack on each side of the segment (there must be a stud between cracks). There is no limit to crack length. | Permitted for inspection interval of 1500 hours. |
| | Two or more cracks on the same side of the segment. One crack from the segment edge to the swirler hole edge is permitted, with all other cracks less than half the distance from the segment edge to the swirler hole edge. | Permitted for inspection interval of 750 hours. |
| | Two or more cracks on the same side of the segment with crack length more than half the distance from the segment edge to the swirler hole edge. | Permitted for inspection interval of 375 hours. |
| | All cracks that can connect and cause material liberation less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. If the segment material is liberated, do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All cracks that can connect and cause material liberation more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
NOTE: There is no risk of material liberation if there is one crack from the segment edge to the swirler hole edge and the adjacent cracks are less than at two thirds distance from the segment edge to the swirler hole edge. | ||
| The front and rear inner and outer liner segments (includes the igniter segment) and the bulkhead panel for surface oxidation or erosion (no burnthrough, burnback or cracks). | All surface burns or erosion. | Permitted for inspection interval of 1500 hours. |
| The front inner and outer liner segment for burnback or burnthrough (does not include the igniter segment). | No burnthrough and no separation of studs. | Permitted for inspection interval of 1500 hours. |
| | All burnback or burnthrough less than 0.250 in. (6.350 mm) and no separation of studs. | Permitted for inspection interval of 750 hours. |
| | All burnback or burnthrough more than 0.250 in. (6.350 mm) and no separation of studs. | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough more than 0.250 in. (6.350 mm) and less than 50 percent separation of one stud from the segment. | Permitted for inspection interval of 150 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough that causes more than 50 percent separation of one stud from the segment. | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| The rear inner and outer liner segment for burnback or burnthrough. | No burnthrough and no separation of studs. | Permitted for inspection interval of 1500 hours. |
| | Burnback around combustion holes less than the length of two hole circumferences. | Permitted for inspection interval of 1500 hours. |
| | All burnback or burnthrough less than 0.250 in. (6.350 mm) and no separation of studs. | Permitted for inspection interval of 750 hours. |
| | All burnback or burnthrough more than 0.250 in. (6.350 mm) and no separation of studs. | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | Burnback or burnthrough around combustion holes that can cause the shell to be in view for less than the length of five hole circumferences. | Permitted for inspection interval of 375 hours. |
| | Burnback around combustion holes that can cause the shell to be in view for less than the length of five hole circumferences. | Permitted for inspection interval of 375 hours. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) less than 0.400 in.2 (258.064 mm2). | Permitted for inspection interval of 375 hours. If it looks like liner segment material is liberated, do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough less than 0.250 in. (6.350 mm) and less than 50 percent separation of one stud from the segment. | Permitted for inspection interval of 150 hours. |
| | All burnback or burnthrough that causes more than 50 percent separation of one stud from the segment. | Not permitted. Remove the engine in 30 flight cycles or less. |
| | Burnback around combustion holes that can cause the shell to be in view for more than the length of five hole circumferences. | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) more than 0.400 in.2 (258.064 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| The bulkhead segments for burnback or burnthrough | All burnback or burnthrough less than 0.125 in. (3.175 mm) in length maximum. | Permitted for inspection interval of 1500 hours. |
| | All burnback or burnthrough between 0.125 in. (3.175 mm) and 0.250 in. (6.350 mm) in length maximum. | Permitted for inspection interval of 750 hours. |
| | All burnback or burnthrough between 0.250 in. (6.350 mm) and 0.500 in. (12.700 mm) in length maximum and no separation of studs. | Permitted for inspection interval of 375 hours. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough that causes less than 50 percent separation of one stud from the segment. | Permitted for inspection interval of 150 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough that causes more than 50 percent separation of one stud from the segment. | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All burnback or burnthrough more than 0.500 in. (12.700 mm) in length maximum. | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| The igniter segment for burnback or burnthrough (for shell damage below the igniter segment see shell section). | All burnback or burnthrough less than 0.125 in. (3.175 mm) in length maximum. | Permitted for inspection interval of 1500 hours. |
| | All burnback or burnthrough between 0.125 in. (3.175 mm) and 0.250 in. (6.350 mm) in length maximum. | Permitted for inspection interval of 750 hours. |
| | All burnback or burnthrough between 0.250 in. (6.350 mm) and 0.500 in. (12.700 mm) in length maximum. | Permitted for inspection interval of 375 hours. |
| | All burnback and burnthrough that can cause material liberation (with or without cracks) less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough more than 0.500 in. (12.700 mm) in length maximum and less than 50 percent separation of one stud from the segment. | Permitted for inspection interval of 150 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All burnback or burnthrough that causes more than 50 percent separation of one stud from the segment. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The combustor inner and outer liner shell for cracks (does not include the area between the combustion holes and around the igniter guides). | All cracks less than 0.500 in. (12.700 mm) in length maximum. | Permitted for inspection interval of 1500 hours. |
| | All cracks between 0.500 in. (12.700 mm) and 0.750 in. (19.050 mm) in length maximum. | Permitted for inspection interval of 750 hours. |
| | All cracks more than 0.750 in. (19.050 mm) in length maximum. | Permitted for inspection interval of 375 hours. |
| | All cracks that can cause material liberation less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | All cracks that can cause material liberation more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| The combustor shell for burnback or burnthrough (with or without cracking). Includes the inner shell, outer shell and bulkhead shell for burnback and burnthrough (in zone A). | All surface burns or erosion without burnback or burnthrough. | Permitted for inspection interval of 1500 hours. |
| | Burnback or burnthrough that can cause a total shell open area (inner, outer and bulkhead) less than 0.250 in.2 (161.29 mm2). Count each full perimeter of a combustion hole as 0.200 in.2 (129.032 mm2). | Permitted for inspection interval of 750 hours. |
| | Burnback or burnthrough that can cause a total shell open area (inner, outer and bulkhead) less than 1.000 in.2 (645.16 mm2). Count each full perimeter of a combustion hole as 0.200 in.2 (129.032 mm2). | Permitted for inspection interval of 375 hours. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) less than 0.250 in.2 (161.29 mm2). | Permitted for inspection interval of 375 hours. Do the borescope inspection of the HPT 1st stage blade (Ref. AMM TASK 72-51-00-290-802). |
| | Burnback or burnthrough that can cause a total shell open area (inner, outer and bulkhead) more than 1.000 in.2 (645.16 mm2). Count each full perimeter of a combustion hole as 0.200 in.2 (129.032 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| | All burnback or burnthrough that can cause material liberation (with or without cracks) more than 0.250 in.2 (161.29 mm2). | Not permitted. Remove the engine in 30 flight cycles or less. |
| | Shell oxidation on the outer burner liner behind the igniter segment. | Not permitted. Remove the engine in 10 flight cycles or less. |
| The combustor outer liner shell at igniter guides and welds. | One crack per boss less than 0.250 in. (6.350 mm) in length maximum. | Permitted for inspection interval of 1500 hours. |
| | One crack per boss more than 0.250 in. (6.350 mm) in length maximum. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The bulkhead shell for cracks outside zone A. | All cracks. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The bulkhead shell for cracks in zone A. | All cracks not more than 0.750 in. (19.050 mm) in length maximum | Permitted for inspection interval of 750 hours. |
| | All cracks more than 0.750 in. (19.050 mm) in length maximum. | Permitted for inspection interval of 375 hours. |
| The bulkhead liner shell for burnback or burnthrough (in an area of four bulkhead segments). | All quantities of open areas. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The bulkhead liner shell for burnback or burnthrough outside of zone A. | All quantities of open areas. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The inner, outer and bulkhead liner segments for loose or missing nuts. | Maximum quantity of one missing nut per liner segment allowed at all locations on the liner segment and five missing nuts per engine combustion chamber assembly. | If missing nut(s) is (are) not in view, then do the borescope inspection of the HPT (Ref. AMM TASK 72-51-00-290-802). If damage is found on the HPT, then do the borescope inspection of the LPT (Ref. AMM TASK 72-53-00-200-801). |
| Air swirler for soot deposits on the inner and outer lip surfaces. | All quantities that do not block the swirler air passage exit plane between the inner and outer lips. | Permitted for inspection interval of 750 hours. |
| | Soot deposits that block the air passage exit plane between the inner and outer lips. | Contact Pratt & Whitney. |
| | All quantities on the internal surface of the inner swirler lip. | Permitted for inspection interval of 750 hours. |
| | Soot layer that collects thicker than 0.100 in. (2.540 mm) on the internal surface of the inner swirler lip. | Contact Pratt & Whitney. |
| Air swirler for surface erosion and oxidation on the inner and outer lip surfaces. | All quantities. | Permitted for inspection interval of 750 hours. |
| | Erosion or oxidation that touches the bulkhead segment face. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The fuel nozzle tip for soot deposits. | All quantities that do not block the fuel openings on the tip center or tip sides. | Permitted for inspection interval of 750 hours. |
| | Soot deposits that block all quantities of the fuel openings on the fuel nozzle tip. | Contact Pratt & Whitney. |
| The fuel nozzle tip for erosion or oxidation. | Erosion or oxidation not more than 25 percent of the fuel nozzle tip if it does not block the fuel openings and does not extend down the sides of the nozzle. | Permitted for inspection interval of 750 hours. |
| | Distress which is more than 25 percent of the nozzle tip or blocks the fuel openings on the nozzle tip. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The igniter guide area for burnthrough areas. | All quantities. | Not permitted. Remove the engine in 30 flight cycles or less. |
| The outer combustor conformal seal (space between the outer rear segment and 1st stage vane leading edge). | Surface erosion, burnback and cracks in all quantities of locations. | Permitted for regular inspection interval of 1500 hours. |
| | Through-thickness crack or complete burnback of the seal in one or more locations. | Contact Pratt & Whitney. |
| | Seal material that can liberate or has liberated. | Contact Pratt & Whitney. |
Table - Combustion Chamber Area Borescope Inspection
| EXAMINE | DAMAGE | DISPOSITION |
|---|---|---|
| All airfoil surfaces (including the leading and the trailing edges) and inner diameter/outer diameter vane platforms for nicks and dents. | All quantities not more than 0.010 in. (0.254 mm) in depth and not more than 0.100 in. (2.540 mm) in diameter. | Permitted for inspection interval of 1500 hours. |
| | The dent must not block a cooling hole by more than 50 percent. | Permitted for inspection interval of 1500 hours. |
| | There must be 0.050 in. (1.270 mm) minimum distance between two nicks or dents. | Permitted for inspection interval of 1500 hours. |
| | No nicks or dents are in 0.150 in. (3.810 mm) radial distance from airfoil (fillet surface) to inner diameter and outer diameter platforms. | Permitted for inspection interval of 1500 hours. |
| | No nicks or dents on the airfoil trailing edge. | Permitted for inspection interval of 1500 hours. |
| | All damage beyond the regular inspection interval. | Not permitted. Remove the engine in 10 flight cycles or less. |
| The airfoil leading edge for: | | |
| Burning/erosion | A maximum of 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for regular inspection interval. |
| | More than 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for inspection interval of 750 hours. |
| Burnthrough/material breakthrough | No more than 0.030 in. (0.762 mm) of burnthrough or material breakthrough if the burnthrough does not extend into the adjacent region and there is no additional burnthrough on the vane concave region. | Permitted for inspection interval of 750 hours. |
| | All quantities more than 0.030 in. (0.762 mm) or burnthrough that extends into adjacent region, or burnthrough on both convex and concave regions of a vane, are not permitted. | Remove the engine in 30 flight cycles or less. |
| The airfoil convex surface for: | Any quantity of burnthrough on exposed baffle. | Remove the engine in five cycle or less. |
| Burning/erosion | A maximum of 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material | Permitted for regular inspection interval. |
| | More than 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for inspection interval of 750 hours. |
| Burnthrough/material breakthrough | Not permitted. | Remove the engine in 30 flight cycles or less. |
| The airfoil concave surface for: | | |
| Burning/erosion | A maximum of 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for regular inspection interval. |
| | More than 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for inspection interval of 750 hours. |
| Burnthrough/material breakthrough | All quantities to a maximum of 0.010 in.2 (6.452 mm2) are permitted for each vane. | Permitted for inspection interval of 750 hours. |
| | All quantities to a maximum of 0.023 in.2 (14.839 mm2) are permitted for each vane. | Permitted for inspection interval of 375 hours. |
| | All quantities more than 0.023 in.2 (14.839 mm2) are not permitted. | Remove the engine in 30 flight cycles or less. |
| | Any quantity of burnthrough in exposed baffle. | Remove the engine in five cycles or less. |
| The airfoil trailing edge for: | | |
| Burnback | Less than 0.075 in. (1.905 mm) distance axially from the trailing edge. | Permitted for regular inspection interval. |
| | More than 0.075 in. (1.905 mm) and less than 0.150 in. (3.810 mm) distance axially from the trailing edge (rear-most concave airfoil cooling holes are located 0.150 in. (3.810 mm) from the trailing edge). | Permitted for inspection interval of 750 hours. |
| | More than 0.150 in. (3.810 mm) distance axially from the trailing edge (rear-most concave airfoil cooling holes are located 0.150 in. (3.810 mm) from the trailing edge). | Remove the engine in 30 flight cycles or less. |
| The inner and outer platforms for: | | |
| Burning/erosion | A maximum of 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for regular inspection interval. |
| | More than 0.75 in.2 (483.87 mm2) x 0.030 in. (0.762 mm) in depth with exposed parent material. | Permitted for inspection interval of 750 hours. |
| Burnthrough/material breakthrough | One location maximum up to 0.021 in.2 (13.548 mm2) for each vane up to a maximum of four vanes. | Permitted for inspection interval of 750 hours. |
| | One location maximum up to 0.043 in.2 (27.742 mm2) for each vane up to a maximum of four vanes. | Permitted for inspection interval of 375 hours. |
| | One location more than 0.043 in.2 (27.742 mm2) not permitted. More than four vanes are not permitted. | Remove the engine in 30 flight cycles or less. |
| The leading edge for cracks | Cracks that make a closed loop. | Remove the engine in ten cycles or less. |
| | Cracks on the vane if each crack extends between two adjacent cooling holes, no more than one crack on each hole. | Permitted for inspection interval of 1500 hours. |
| | 0.150 in. (3.810 mm) in maximum length. | Permitted for inspection interval of 1500 hours. |
| | More than 0.150 in. (3.810 mm) in length. | Permitted for inspection interval of 750 hours. |
| | One crack is permitted not more than the length of 0.250 in. (6.350 mm) from the platform. | Permitted for inspection interval of 1500 hours. |
| | Cracks more than 0.250 in. (6.350 mm) from the platform. | Remove the engine in ten cycles or less. |
| The concave and convex airfoil surfaces for: | All quantities of single cracks no more than 0.150 in. (3.810 mm) in length. | Permitted for inspection interval of 1500 hours. |
| | Three cracks maximum for each vane no more than 1.000 in. (25.400 mm) in combined length. | Permitted for inspection interval of 1500 hours. |
| | One crack can intersect with another crack at only one location if the combined length is not more than 0.500 in. (12.700 mm). | Permitted for inspection interval of 1500 hours. |
| | More than three cracks or more than 1.000 in. (25.400 mm) in combined length. | Permitted for inspection interval of 750 hours. |
| | Cracks than make a closed loop. | Remove the engine in ten flight cycles or less. |
| The trailing edge for: | Cracks from trailing edge not more than 0.150 in. (3.810 mm). Cannot intersect with other cracks. | Permitted for inspection interval of 1500 hours. |
| | Cracks from trailing edge more than 0.150 in. (3.810 mm) and less than 0.200 in. (5.080 mm). Cannot intersect with other cracks. | Permitted for inspection interval of 750 hours. |
| | Cracks that intersect. | Remove the engine in ten flight cycles. |
| The inner diameter and outer diameter platform surface (includes fillet radii) for: | A maximum of three radial cracks that do not extend more than 0.250 in. (6.350 mm) in height from the platform surfaces. | Permitted for inspection interval of 1500 hours. |
| | More than three radial cracks that extend more than 0.250 in. (6.350 mm) in length from the platform surfaces. | Not permitted. Remove the engine in ten flight cycles or less. |
| | All quantities or cracks not more than 0.150 in. (3.810 mm) in length in the inner diameter and outer diameter platform surfaces. | Permitted for inspection interval of 1500 hours. |
| The inner diameter and outer diameter platform edge for cracks: | All quantities not more than 0.125 in. (3.175 mm) in length. | Permitted for inspection interval of 1500 hours. |
| Intersecting cracks | Not permitted. | Not permitted. Remove the engine in ten flight cycles or less. |
| Missing material | Not permitted. | Not permitted. Remove the engine in ten flight cycles or less. |
| Seal slots for: | | |
| Cracks | Cracks can go into the gaspath side of the seal slot if they are 0.100 in. (2.540 mm) apart minimum. | Permitted for inspection interval of 1500 hours. |
| | Crack length must not be more than the seal slot depth. | Permitted for inspection interval of 1500 hours. |
| | Cracks must be tight and show no signs of burning. | Permitted for inspection interval of 1500 hours. |
| Intersecting cracks | Not permitted. | Not permitted. Remove the engine in ten flight cycles or less. |
| Missing material | Not permitted. | Not permitted. Remove the engine in ten flight cycles or less. |
| All the airfoil surfaces for: | | |
| Missing ceramic coat | All quantities are permitted. | Permitted for regular inspection interval. |
| Cracks on ceramic coat | All quantities are permitted. | Permitted for regular inspection interval. |
Table - HPT 1st Stage Vane Assembly Inspection
(7) Install borescope plug access-port DIFF-1 (Ref. AMM TASK 72-00-00-400-804). (8) If necessary, install the igniter plug(s) at the three and four o'clock locations (Ref. AMM TASK 74-21-01-400-801).
(9) Examine the assembly for foreign objects, damage and correct assembly.
Subtask 72-41-00-860-050-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(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 72-41-00-440-054-A ** ON A/C NOT FOR ALL (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.
B. Do the reactivation of the thrust reverser system after maintenance (Ref. AMM TASK 78-30-00-440-805).
Subtask 72-41-00-410-058-A ** ON A/C NOT FOR ALL