Inspection of the Engine (After Surge or Stall) [PW11]

TASK 72-00-00-200-809-A
Inspection of the Engine (After Surge or Stall)

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.

ZONE: 400
FIN: 4020KM1 ** ON A/C NOT FOR ALL
FIN: 4020KM2 ** ON A/C NOT FOR ALL

1. Reason for the Job
A. Use this inspection procedure to examine the engine for damage after a power surge or stall.

NOTE: An engine surge or stall condition occurs when the airflow through the engine is interrupted and begins to flow in the opposite (forward) direction. This can be momentary, recoverable (engine returns to its original running parameters) and barely noticeable; or a significant flow interruption resulting in an audible "bang" with flame out of the tailpipe or possibly inlet. This type of event can be non-recoverable, with the engine being shut down and possible engine damage.

B. General
(1) Refer to the procedure 71-00-00-860-819.
(2) Do an inspection of the engine after a power surge or a high power surge.
(a) A high power engine surge event for the purpose of this inspection is defined as a surge with a burner pressure of more than 530 psig (3654 kPa) that occurs below 17,000 ft (5181 m) altitude and during takeoff, maximum continuous, maximum climb, holding or thrust reverser operation power settings. Refer to Steps 4.A.(2) and 4.A.(3).
(b) Do the inspection after a power surge if the surge burner pressure is between 350 and 530 psig (2414 to 3654 kPa). Refer to Steps 4.A.(2) only.

NOTE: It is not necessary to do the high power surge inspection.

(c) The surge can or cannot be recoverable.
(3) When a high power surge with a burner pressure of more than 530 psig (3654 kPa) occurs, a focused borescope inspection of the 2nd, 3rd, 4th, 5th and 6th High Pressure Compressor (HPC) integral blade rotor trailing edge fillet runout and an inspection of the Low Pressure Compressor (LPC) blades and vanes for damage is necessary. Refer to Steps 4.A.(2) and 4.A.(3).
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	COVER - PROTECTION

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 71-00-00-860-832-A	Procedure to Prevent Engine Motoring and to Stop the Electrical Supply to the EEC
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 72-00-00-210-809-A	Visual Examination (after an Exhaust Gas Temperature (EGT) Overtemperature)
TASK 72-00-00-210-810-A	Inspection of the Engine after N1/N2 Over Speed Operation
TASK 72-00-00-210-813-A	General Visual Inspection (GVI) of the Engine Inlet Area
TASK 72-00-00-210-816-A	Visual Examination of the Engine
TASK 72-00-00-290-811-A	Borescope Inspection of the Engine
TASK 72-31-00-290-802-A	Borescope Inspection of the Low Pressure Compressor (LPC) Assembly
TASK 72-53-00-220-801-A	Detailed Visual Inspection (DVI) of the Low Pressure Turbine (LPT) 3rd Stage Blades and Outer Air Seals
TASK 75-00-00-210-802-A	Visual Examination of the Engine Air Systems
TASK 75-31-00-200-802-A	Mechanical Check of the High Pressure Compressor (HPC) Stator Vane Control System
TASK 75-31-00-200-803-A	Mechanical Check of the Low Pressure Compressor (LPC) Stator Vane Control System
TASK 77-11-22-000-801-A	Removal of the NF Speed Probe
TASK 77-11-22-210-801-A	Visual Inspection of NF Speed Probe
TASK 77-11-22-400-801-A	Installation of the NF Speed Probe
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
Inspection of the Engine after Surger or Stall - (Trailing Edge Fillet Runout Crack)
Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction)
Inspection of the Engine after Surge or Stall - (Misaligned Vane)
Inspection of the Engine after Surge or Stall - (Borescope Examination for LPC Damage)

3. Job Set-up
Subtask 72-00-00-941-200-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring and to stop the electrical supply to the Electronic Engine Control (EEC)
(Ref. AMM TASK 71-00-00-860-832).

Subtask 72-00-00-010-369-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 an ACCESS PLATFORM 1M(3 FT) in position.

Subtask 72-00-00-040-175-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 72-00-00-010-370-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
Subtask 72-00-00-220-179-A ** ON A/C NOT FOR ALL

A. Inspection of the Engine (After Surge or Stall)

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

(1) Removal of the protection covers

CAUTION: REMOVE THE PROTECTION COVERS FROM THE OPENINGS AS NECESSARY TO PREVENT ENGINE DAMAGE.

(a) Make sure that you remove all the necessary COVER - PROTECTION to prevent damage to the engine.
(2) Do an inspection after a surge (burner pressure more than 350 psig (2414 kPa)) as follows:

NOTE: If a power surge occurs with a burner pressure from 350 psig (24.13 bar) to 530 psig (36.54 bar), engine airflow in the opposite or forward direction during the surge can cause the NF speed probe to hit the fan shaft. After a hit, there can be damage to the fan shaft and the NF speed probe. Debris can also cause damage to the local mechanical components.

(a) Do an inspection of the LPC after a power surge has occurred as follows:
1 Do a borescope inspection of the forward edge of the blade tips and the aft edge of the vanes for indications of hits (Ref. AMM TASK 72-31-00-290-802)

Inspection of the Engine after Surge or Stall - (Borescope Examination for LPC Damage) ** ON A/C NOT FOR ALL

a Make sure the LPC Inlet Guide Vanes (IGV) and LPC stages one through three are inspected.
2 Damage found must be in the limits (Ref. AMM TASK 72-31-00-290-802).
3 Do the borescope inspection in the lesser of ten hours of engine operation time or five flight cycles after a power surge.
(b) Examine the LPC IGVs for misalignment as follows:

NOTE: For the purposes of this inspection, a misaligned vane is a vane that is noticeably rotated about its axis, at a different angle than the remainder of the vanes in the set.

1 Move the LPC Stator Vane Actuator (SVA) to the fully open position (Ref. AMM TASK 75-31-00-200-803).
2 Put the flexible borescope through AP LPC-1 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

3 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the IGVs. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
4 Move the LPC SVA to the fully closed position (Ref. AMM TASK 75-31-00-200-803).
5 Put the flexible borescope through AP LPC-1 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

6 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the IGVs. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
7 Contact Pratt and Whitney if any vanes are noticeably misaligned

Inspection of the Engine after Surge or Stall - (Misaligned Vane) ** ON A/C NOT FOR ALL

(c) Inspect LPC IGV actuation system sync rings, vane arms, and vane arm claws for any distress, distortion, or separation. (Ref. AMM TASK 75-00-00-210-802).
(d) Do a check of the ground scanning report to make sure that there are no faults related to the NF speed probe as follows:
1 If there are no NF speed probe faults found, no procedures are necessary.
2 If NF speed probe faults are found, do the steps that follow:
a Remove the NF speed probe (Ref. AMM TASK 77-11-22-000-801).
b Examine the NF speed probe (Ref. AMM TASK 77-11-22-210-801).
c Install the NF speed probe (Ref. AMM TASK 77-11-22-400-801).
(3) Do an inspection after a high power surge has occurred (Pb of more than 530 psig (3654 kPa)).

NOTE: If a high power surge occurs, engine airflow in the opposite or forward direction during a surge can cause High Pressure Compressor (HPC) blade airfoil cracks. The cracks could initially be too small to be seen by borescope inspection. If not repaired, cracks can become airfoil fractures with more HPC damage and an unrecoverable engine surge. For location and appearance of a trailing edge fillet runout crack caused by a power surge

Inspection of the Engine after Surger or Stall - (Trailing Edge Fillet Runout Crack) ** ON A/C NOT FOR ALL

(a) Inspection of the 2nd, 3rd, 4th, 5th, and 6th stage HPC trailing edge runout is necessary to find and repair cracks that could become fractures.
(b) It is necessary to examine all 2nd, 3rd, 4th, 5th, and 6th stage HPC airfoils at the trailing edge fillet runout.
(c) Trailing edge fillet runout cracks identified during all inspections make it necessary to remove the engine before additional flights.
(d) Do the inspection in the lesser of 10 hours of engine operation time or five flight cycles after a high power surge occurs.
(e) Examine the IGV, 1st, 2nd, and 3rd stage HPC vanes for vanes that are not aligned as follows:

NOTE: A vane that is not aligned is turned along its axis, at a different angle than the adjacent vanes.

1 Move the HPC SVA to the fully open position (Ref. AMM TASK 75-31-00-200-802).
2 Put the flexible borescope through AP HPC-1 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

3 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the IGVs. The borescope must stay in focus on the leading edges of the airfoils. It can be helpful to record during the inspection process.
4 Put the flexible borescope through AP HPC-2 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

5 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the 1st stage vanes. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
6 Put the flexible borescope through AP HPC-3 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

7 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the 2nd stage vanes. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
8 Put the flexible borescope through AP HPC-4 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

9 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the 3rd stage vanes. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
10 Move the HPC SVA to the fully closed position (Ref. AMM TASK 75-31-00-200-802).
11 Put the flexible borescope through AP HPC-1 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

12 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the IGVs. The borescope must stay in focus on the leading edges of the airfoils. It can be helpful to record during the inspection process.
13 Put the flexible borescope through AP HPC-2 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

14 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the 1st stage vanes. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
15 Put the flexible borescope through AP HPC-3 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

16 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the 2nd stage vanes. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
17 Put the flexible borescope through AP HPC-4 and wind counterclockwise (aft looking forward) until the borescope port is in view

Inspection of the Engine after Surge or Stall - (Borescope Installation and Removal Direction) ** ON A/C NOT FOR ALL

18 Examine the vanes as you retract the borescope. The borescope must be retracted slowly to get a clear view of the airfoil at the outboard side of the 3rd stage vanes. The borescope must stay in focus on the trailing edges of the airfoils. It can be helpful to record during the inspection process.
19 Contact Pratt and Whitney if any vanes are not aligned

Inspection of the Engine after Surge or Stall - (Misaligned Vane) ** ON A/C NOT FOR ALL

(4) Do a visual inspection of the turbine exhaust area and low pressure turbine 3rd stage rotor (Ref. AMM TASK 72-53-00-220-801).
(a) Look for cracks, burning or deformation of parts.
(b) Look for pieces of metal in the exhaust area.
(5) Do a visual examination of the inlet area and fan rotor (Ref. AMM TASK 72-00-00-210-813).
(a) Look for cracks, burning or deformation of parts.
(b) Look for pieces of metal or part debris in the inlet area.
(6) If engine operation limits such as EGT overtemperature or rotor speeds are not in limits, you must inspect the other items that could have damage (Ref. AMM TASK 72-00-00-210-809) and (Ref. AMM TASK 72-00-00-210-810).
(7) If the engine was operated at higher power settings when the surge or stall occurred and the engine was in a hot condition and shut down quickly, or for emergency (without the normal cool-down period), examine the engine external parts (Ref. AMM TASK 72-00-00-210-816).
(a) Look for cracks, damage, visual deterioration or deformation.
(8) Find the cause of the surge.
(a) If the cause of the forward or reverse surge cannot be determined after following the referenced procedures, do a borescope inspection of the engine modules to ensure that there is no internal engine damage (Ref. AMM TASK 72-00-00-290-811).
(9) If the engine must be removed from the aircraft because of damage or limit exceeded, you must do the steps that follow:
(a) Record the surge or stall and the time the engine became stable or shut down.
(b) Record if the surge or stall occurred at a stable condition or temporary conditions.
(c) Record all other important information that happened during the surge or stall. All the records must go with the engine history records.
(d) Send the engine to the shop for disassembly and repair.
(10) Examine the assembly for foreign objects, damage and correct assembly.
(11) Installation of the protection covers

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

(a) Make sure that you install COVER - PROTECTION as necessary to prevent damage to the engine.

5. Close-up
Subtask 72-00-00-410-320-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 72-00-00-440-165-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 72-00-00-410-321-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] 2026.04.02 06:34:39 UTC