ALERT SERVICE BULLETIN REVISION NOTICE

ENGINE — AIR SEAL ASSEMBLY, 2ND STAGE HIGH PRESSURE TURBINE (HPT) —

INSPECTION OF THE SEAL FOR CRACKS

Turbojet Engine Service Bulletin No. PW4G-112-A72-330 Revision No. 2 dated July 11, 2013.

Revision History

Original Issue December 3, 2012

Revision 1 dated February 14, 2013

Revision 2 dated July 11, 2013

Reason for the Revision

To replace NDIP-1137, Revision B with NDIP-1137, Revision C dated June 19, 2013.

The List of Required Tools in the Necessary Tools section was updated.

The Training and Certification for the inspection personnel is found in NDIP-1137. The same

information was removed from the Accomplishment Instructions because it is not necessary to

state it again.

The Accomplishment Instructions step “One isolated spike of greater than 1.2 volts after a 2nd EC

inspection is performed would be considered acceptable to continue in service if this Service Bulletin

inspection is performed on a reduced interval of 600 cycles.” was changed to “One isolated spike

of greater than 1.2 volts after a 2nd EC inspection is performed would be considered acceptable

to continue in service if this Service Bulletin inspection is performed on a reduced interval of 600

cycles. During that next 600 cycle interval if there are no isolated spikes of greater than 1.2 volts for

two EC inspections the engine could return to the 1200 cycle inspection interval.”

More HPT stage 2 air seal OD cavity surface inspection criteria was added in the Accomplishment

Instructions.

Effect of Revision on Prior Compliance

None.

This is a Complete Revision (Not Applicable to the SGML version)

The contents are in accordance with the list of effective pages. All pages have the current revision

number. Technical changes are marked with black bars.

Non-Destructive Inspection Procedures

NDIP-1137, Revision C dated June 19, 2013 is attached. Please discard the previously issued copy.

MODEL APPLICATION

PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3

BULLETIN ISSUE SEQUENCE

PW4G-112 Series A72-330

P&W Distribution Code

2642 PW4G-112-A72-330

Page 1 of 2

Published in United States of America

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Page Revision No. Date

1 thru 32 2 July 11/13

A copy of this Revision Notice and any future revision notices must be filed as a permanent

record with your copy of the subject bulletin.

PW4G-112-A72-330

Page 2

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
ALERT SERVICE BULLETIN

ENGINE — AIR SEAL ASSEMBLY, 2ND STAGE HIGH PRESSURE TURBINE (HPT)

— INSPECTION OF THE SEAL FOR CRACKS

MODEL APPLICATION

PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3

BULLETIN ISSUE SEQUENCE

PW4G-112 Series A72-330

ATA NUMBER

72-52-00

UTC/P&W PROPRIETARY INFORMATION

This document is the property of United Technologies Corporation — Pratt & Whitney (UTC/P&W). You may not possess,

use, copy or disclose this document or any information in it, for any purpose, including without limitation to design,

manufacture, or repair parts, or obtain FAA or other government approval to do so, without UTC/P&W’s express written

permission. Neither receipt nor possession of this document alone, from any source, constitutes such permission.

Possession, use, copying or disclosure by anyone without UTC/P&W’s express written permission is not authorized

and may result in criminal and/or civil liability.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).

Compliance Category

3

P&W Distribution Code

2642

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 1 of 32

Published in United States of America
Summary

The function of this Alert Service Bulletin is to provide a Non-Destructive Inspection Procedure

(Reference 16, NDIP-1137) for an Eddy Current Inspection (ECI) of the Air Seal Assembly in the 2nd

Stage High Pressure Turbine (HPT), PN 54L041. This inspection is to find cracks in the forward Outer

Diameter (OD) radii. See Reference 16, NDIP-1137, Figure 1 for the inspection area. This inspection

will need to be done again until a new Service Bulletin is released that supplies a new design air seal.

Planning Information

Effectivity Data

Engine Models Applicable

PW4074, PW4077

Engine Serial Nos. — All engines that have a 2nd Stage HPT Air Seal, PN 54L041 installed

(Post Reference 13, Service Bulletin No. PW4G-112-72-271).

PW4074D, PW4077D, PW4084D, PW4090, PW4090-3

Engine Serial Nos. — All engines that have a 2nd Stage HPT Air Seal, PN 54L041 installed

(Post Reference 13, Service Bulletin No. PW4G-112-72-271).

Concurrent Requirements

There are no concurrent requirements.

Reason

1. Problem: Cracks are starting, and increasing in size, in the 2nd stage HPT Air Seal,

PN 54L041, at the forward OD area of the part. The cracks can cause an engine event.

2. Cause: An investigation has determined that loading on the forward OD flange can

cause cracks on the OD radius of the HPT 2nd stage air seal.

3. Solution: Do an Eddy Current Inspection of the 2nd Stage air seal to find cracks.

Description

Inspect the 2nd Stage HPT Air Seal, PN 54L041, to find cracks. See Figure 1.

Compliance

Category 3

Do this Alert Service Bulletin as follows:

PN 54L041 Air Seals that have accumulated less than or equal to 1,200 total cycles since

new, when this Alert Service Bulletin is released, must be inspected within 2,200 Total

Cycles (TC) since new. Air Seals that have accumulated more than 1,200 total cycles

since new, when this Alert Service Bulletin is released, must be inspected within 1,000

cycles of Alert Service Bulletin release. Once the inspection is accomplished, it must be

repeated every 1,200 cycles until the engine is removed. This information is also shown

in the table below.

If a piece part air seal is in the shop after the of release of this Alert Service Bulletin, and is

inspected using Fluorescent Penetrant Inspection (FPI) per the requirements in Reference

4, CIR Manual, and shows no crack indications, the part will require an Eddy Current

Inspection within 1,200 cycles following that piece part FPI.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 2

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Air Seal Inspection Intervals

Engine Model

Total Part Cycles

Since New (TC)

Initial Inspection

Threshold

Cycles

Subsequent

Inspection

Cycles

TC ≤ 1200 2,200 1,200

TC > 1200 1,000 1,200

PW4074, PW4077, PW4074D,

PW4077D, PW4084D, PW4090,

PW4090-3

TC > 1200 and

Air Seal receives

in-shop FPI per

Reference 4, CIR

Manual

1,200 1,200

CAUTION: CUMULATIVE TOTAL AIR SEAL CYCLES MUST NOT EXCEED

REFERENCE 5 OR 6, ENGINE MANUAL, CHAPTER 5 LIFE. IF THE

CHAPTER 5 LIFE CYCLE IS EXCEEDED, THE PART IS NOT AUTHORIZED

FOR USE.

Approval Data

The times between inspections specified in Compliance and the inspection procedures

specified in the Accomplishment Instructions agree with the applicable Federal Aviation

Regulations and are FAA-Approved for the engine model(s) given.

Manpower

The estimate of man-hours of labor directly necessary to do the intent of this Alert Service

Bulletin are as follows:

1. Open the cowl doors .......................................................................................... 1.0

2. Remove the parts to gain access to the HPT turbine exhaust case manifold

port ..................................................................................................................... 0.5

3. Do Reference 16, NDIP-1137 Eddy Current Inspection ..................................... 2.0

4. Install the parts that were removed for access .................................................. 0.5

5. Close the cowl doors .......................................................................................... 1.0

6. Total Necessary Man-hours ............................................................................... 5.0

Weight Data

No Change.

Electrical Load Data

Not Applicable.

Software Accomplishment Summary

Not Applicable.

References

1. Turbojet Engine Standard Practices Manual, Part No. 585005.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 3

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
2. PW4074, PW4077 Turbofan Engines, Illustrated Parts Catalog, Part No. 51A346.

3. PW4074D, PW4077D, PW4084D, PW4090, PW4090-3, PW4090D, PW4098 Turbofan

Engines, Illustrated Parts Catalog, Part No. 51A742.

4. PW4000 Series 112 Inch PW4074, PW4077, PW4077D, PW4084D, PW4090, PW4098

Turbofan Engines, Engine Cleaning, Inspection And Repair (CIR) Manual, Part No.

51A750.

5. PW4074, PW4077 Turbofan Engines, Engine Manual, Part No. 51A345.

6. PW4074D, PW4077D, PW4084D, PW4090, PW4090-3, PW4090D, PW4098 Turbofan

Engines, Engine Manual, Part No. 51A751.

7. Boeing 777 Aircraft Maintenance Manual (AMM).

8. Service Bulletin No. PW4G-112-72-77; Engine — Seal Assembly, Second Stage HPT

Air — Replacement Or Modification Of; The Air Seal Assembly For Improved Durability.

Issue Sequence 72-77, PW4G-112 Series.

9. Alert Service Bulletin No. PW4G-112-A72-172; Engine — Seal Assembly, Air, 2nd Stage

High Pressure Turbine (HPT) — Borescope Inspection For Cracks And Cycle Limit

Reduction. Issue Sequence 72-172, PW4G-112 Series.

10. Alert Service Bulletin No. PW4G-112-A72-197; Engine — Seal Assembly, Air, 2nd Stage

High Pressure Turbine (HPT) — Borescope Inspection For Cracks And Cycle Limit

Reduction. Issue Sequence 72-197, PW4G-112 Series.

11. Alert Service Bulletin No. PW4G-112-A72-222; Engine — Air Seal Assembly, 2nd Stage

High Pressure Turbine (HPT) — Borescope Inspection For Cracks. Issue Sequence

72-222, PW4G-112 Series.

12. Alert Service Bulletin No. PW4G-112-A72-233; Engine — Air Seal Assembly, 2nd Stage

High Pressure Turbine (HPT) — Inspection For Cracks And Cycle Limit Reduction. Issue

Sequence 72-233, PW4G-112 Series.

13. Service Bulletin No. PW4G-112-72-271; Engine — Seal Assembly, 2nd Stage High

Pressure Turbine (HPT) Air— Replace The Seal Assembly And Related Parts For

Improved Durability. Issue Sequence 72-271, PW4G-112 Series.

14. Service Bulletin No. PW4G-112-75-30; Air — Metering Orifice Plate And Seal Assemblies

— Replacement Of With Gaskets. Issue Sequence 72-30 PW4G-112 Series.

15. Service Bulletin No. PW4G-112-72-84; Engine — Turbine Vane And Blade Modulated

Cooling Air System — Removal Of, To Provide A Weight Saving. Issue Sequence 72-84

PW4G-112 Series.

16. Non-Destructive Inspection Procedure, NDIP-1137, PW4000-112” 2nd Stage HPT Air Seal

Forward Outer Diameter Eddy Current Inspection (On-Wing)

NOTE: References 8. through 15. are shown to help find configurations in relation to

this bulletin.

Publications Changed

See the Material Information Part Number Instruction — Disposition codes for cleaning,

inspection and repair compatibility between the new and old part number(s).

PW4074, PW4077 Turbofan Engines, Illustrated Parts Catalog, Part No. 51A346.

72-52-00, Figure 1

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 4

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
75-25-00, Figure 2, 8 and 9

PW4074D, PW4077D, PW4084D, PW4090, PW4090-3, PW4090D, PW4098 Turbofan

Engines, Illustrated Parts Catalog, Part No. 51A742.

72-52-00, Figure 1

75-25-00, Figure 2 and 9

Interchangeability

Not Applicable.

Information in the Appendix

Alternate Accomplishment Instructions (No)

Progression Charts (Yes)

Added Data (Yes)

Revision to Table of Limits (No)

Inspection Procedures (Yes)

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 5

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Material Information

Material — Cost and Availability

1. The estimated price of new material to do this Alert Service Bulletin depends on which

parts are replaced.

2. There are tool kits, number PWA 107958, and Machida Engine Rotator Kit, and Machida

Video Scope Kit, to do this Alert Service Bulletin. Contact your Pratt & Whitney Tool

Support Services sales manager directly, or by e-mail to pwtools@pw.utc.com for

assistance with new PWA tools, kits, calibrations, and repairs.

3. Part availability information is provided in material data Instructions — Disposition.

Industry Support Program

Not Applicable.

The material data that follows is for each engine.

NOTE: It is possible to use the Chapter/Section and Figure/Item reference number

shown below the old part number to find the part in the Illustrated Parts Catalog.

Because there are many different configurations used, it is frequently necessary

to show more than one group of parts. When this occurs, parts that are

interchangeable are shown line-by-line only, unless this is shown differently.

CAUTION: THE FOLLOWING MATERIAL DATA TABLE(S) ARE ORGANIZED BY

ILLUSTRATED PARTS CATALOG. ALL PARTS IN THE TABLE(S) MAY OR

MAY NOT BE APPLICABLE TO ALL THE ENGINE MODELS SHOWN

IN THE TABLE HEADING. YOU MUST REFER TO THE APPROPRIATE

ILLUSTRATED PARTS CATALOG FOR ENGINE MODEL APPLICABILITY

USING THE OLD PART NUMBER (PN) AND CATALOG SEQUENCE

NUMBER. FAILURE TO INSTALL THE PART(S) IN THE CORRECT

ENGINE MODEL MAY RESULT IN A CONFIGURATION THAT IS NOT FAA

APPROVED.

The material data that follows is for each engine.

For PW4074, PW4077 Engines:

New PN Qty Estimate of Unit

Price ($)

Keyword Old PN Instructions —

Disposition

1 389,400.00 SEAL ASSY —

AIR, HPT, 2STG

54L041

(72-52-00-1-160 B)

(4)(C)(X)

AR 68.60 GASKET

OPTION

ST1142-032

(75-25-00-9-80)

(75-25-00-9-150)

(C)(E)(O1)

AR 61.20 GASKET

OPTION

ST1141-60

(75-25-00-9-130)

(C)(E1)(O2)

AR 196.30 GASKET —

SPRING, TURB

CLG AIR

55T843

(A0946)

(75-25-00-8-40)

(C)(E1)

(V)

AR 74.60 BOLT MS9716-10

(75-25-00-9-140 B)

(C)(E2)

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 6

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
New PN Qty Estimate of Unit

Price ($)

Keyword Old PN Instructions —

Disposition

AR 49.70 BOLT MS9716-05

(75-25-00-9-90)

(75-25-00-9-160)

(C)(E2)

AR 20.20 BOLT ST2601-10

(75-25-00-9-20 A)

(C)(E2)

AR 296.20 BOLT ST2601-16

(75-25-00-9-25 A)

(C)(E2)

AR 63.80 GASKET

OPTION

ST2422-039

(75-25-00-9-10)

(C)(E1)(O3)

AR 45.50 BOLT — TCA MS9715-08

(75-25-00-2-20)

(C)(E2)

1 317.80 GASKET

OPTION

ST1141-03

(75-25-00-2-1)

(C)(E)(O4)

The material data that follows is for each engine.

For PW4074D, PW4077D, PW4084D, PW4090, PW4090-3 Engines:

New PN Qty Estimate of Unit

Price ($)

Keyword Old PN Instructions —

Disposition

1 389,400.00 SEAL ASSY —

AIR, HPT, 2STG

54L041

(72-52-00-1-160 B)

(4)(C)(X)

1 68.60 GASKET

OPTION

ST1142-032

(75-25-00-9-146)

(C)(E)(O1)

AR 61.20 GASKET

OPTION

ST1141-60

(75-25-00-9-130)

(C)(E)(O2)

AR 74.60 BOLT MS9716-10

(75-25-00-9-140 B)

(C)(E2)

AR 49.70 BOLT MS9716-05

(75-25-00-9-90)

(75-25-00-9-160)

(C)(E2)

AR 20.20 BOLT ST2601-10

(75-25-00-9-20 A)

(C)(E2)

AR 296.20 BOLT ST2601-16

(75-25-00-9-25 A)

(C)(E2)

AR 63.80 GASKET

OPTION

ST2422-039

(75-25-00-9-10)

(C)(E1)(O3)

AR 45.50 BOLT — TCA MS9715-08

(75-25-00-2-20)

(C)(E2)

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 7

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
New PN Qty Estimate of Unit

Price ($)

Keyword Old PN Instructions —

Disposition

1 317.80 GASKET

OPTION

ST1141-03

(75-25-00-2-1)

(C)(E)(O4)

2 434.80 GASKET —

SPRING

50U285

(72-25-00-9-145)

(C)(E)

Modification and Spares Information

Estimated part prices are provided when they are available at time of publication. The

Estimate of Unit Price is only for planning purposes and does not constitute a firm

quotation. An asterisk (*) is shown where part pricing information was unavailable. In either

case, contact Pratt & Whitney Spares Management & Logistics for firm quotations.

Parts Modification Conditions

(4) Do an inspection as specified in the Accomplishment Instructions.

Spare Parts Availability

(C) The old part will continue to be supplied.

(E) The old part is an expendable item that is necessary to do this bulletin.

(E1) The old part is an expendable item that may be necessary to do this bulletin

depending on which parts are removed from the engine.

(E2) The old part is a bolt that can break when it is removed from the engine. It

may be necessary to replace it.

(O1) Gasket Option, PN ST1142-032, consists of a gasket, PN ST1112-032

(P14U51-0039-02 PerkinElmer Inc. part number) or PN ST1122-032.

(O2) Gasket Option, PN ST1141-60, consists of a gasket PN P13U51-0049-2

(PerkinElmer Inc. part number) or PN ST1121-60.

(O3) Gasket Option, PN ST2422-039, consists of a gasket PN P14U5N0046-2

(PerkinElmer Inc. part number) and ST2412-039.

(O4) Gasket Option, PN ST1141-03, consists of a gasket PN ST1111-03

(P13U51-0004-2 PerkinElmer Inc. part number) and ST1121-03.

(V) This is the PerkinElmer Inc. part number.

(X) See Reference 2 or 3, Illustrated Parts Catalog for applicable replacement parts.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 8

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Vendor Services or Special Components/Materials

Vendor Services or Special Components/Materials

P&W

Designation

Vendor

Designation

Name Vendor Name & Address

55T843 A0946 GASKET —

SPRING, TURB

CLG AIR

ST2402-039 P14U5N0046-2 GASKET

ST1112-032 P14U51-0039-02 GASKET

ST1111-60 P13U51-0049-02 GASKET

ST1111-03 P13U51-0004-2 GASKET

PERKINELMER INC.

11642 OLD BALTIMORE PIKE

BELTSVILLE, MD 20705-1210

USA

Vendor Manufacturer’s Code: 15284

See Illustrated Parts Catalog Vendor Manufacturer’s Code List

NOTE: EXCEPT FOR WORK OR SUPPLIES TO BE PERFORMED OR FURNISHED

BY PRATT & WHITNEY, IT IS UNDERSTOOD THAT PRATT & WHITNEY

DOES NOT ENDORSE THE WORK PERFORMED BY THE COMPANY OR

COMPANIES NAMED HEREIN OR ANY OTHER COMPANY AND DOES NOT

ACCEPT RESPONSIBILITY TO ANY DEGREE FOR THE SELECTION OF

SUCH COMPANY OR COMPANIES FOR THE PERFORMANCE OF ANY

WORK OR PROCUREMENT OF SUPPLIES.

Material Data for Each Spare Engine

The material for each spare engine is as stated in the preceding material information

section.

Reidentified Parts

Not Applicable.

Necessary Tools

The following tools are required to accomplish this Alert Service Bulletin. Contact your

Pratt & Whitney Customer Representative for information regarding acquiring these tools.

List of Required Tools

KIT NUMBER NOMENCLATURE UNITS PER

ENGINE

PWA 107958* EDDY CURRENT INSPECTION Kit 1

N/A* MACHIDA ENGINE ROTATOR Kit

Model MA-TT-70 with Adapters

1

N/A* MACHIDA VIDEO SCOPE Kit

Model VSC-2-86 with Monitor

1

* Detail tool listing is found in NDIP-1137

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 9

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Other Material Information Data

Not Applicable.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 10

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Accomplishment Instructions

FOR PW4074, PW4077 ENGINES INSTALLED ON AIRCRAFT

1. Open the cowl doors to gain access to the Turbine Vane Cooling Air (TVCA) Ducts. See

Reference 7, Boeing 777 Aircraft Maintenance Manual (AMM) Chapter/Section 71-11-04.

Allow engine to cool.

2. It is permitted to use the optional TVCA duct entry port location for Eddy Current (EC)

inspection access. Remove the Upper Right TVCA Duct (AP01 or AP114) as specified in

Reference 7, Boeing AMM Task 75-25-05-000-818 or the lower left TVCA Duct (AP02) as

specified in Reference 7, Boeing AMM Task 75-25-05-000-819 based on accessibility. The

AP01 or AP114 TVCA Duct is located at the two o’clock position (See Figures 2 through 5)

and the AP02 air duct is located at the four o’clock position (See Figure 6).

The Upper Right TVCA is one of three configurations:

NOTE: Removal of the bolts from the TVCA Duct access ports when the engine is

hot without lubrication can cause the bolts to break. Apply penetration oil

to the TCA Duct Bolts prior to removal per Reference 7, Boeing 777 AMM,

Chapter/Section 70-00-00, SPOP 427. See Chapter/Section 70-00-00, Task

70-00-00-910-808-N00 for repair of broken bolts (SPOP 416).

A. Configuration 1 — Engines with the Modulated TVCA System Pre Reference 15, SB

PW4G-112-72-84. This system has a TVCA valve located between the (AP01) duct

and the (AP05) elbow. With this configuration, you must use O-ring gaskets at all four

HPT case boss locations, (AP01), (AP02), (AP03), and (AP04). See Figure 2 and 4.

B. Configuration 2 — Engines without the Modulated TVCA System (Post Reference 15,

SB PW4G-112-72-84, Method 2). This system has a optional duct (AP115) in place

of the TVCA valve. The duct (AP115) is located between the (AP01) duct and the

(AP05) elbow. With this configuration, you must use O-ring gaskets at the two HPT

case bosses, (AP02) and (AP04). The (AP01) and (AP03) locations use metering

orifice plate and seal assemblies (Engines Pre Reference 14, SB PW4G-112-75-30).

The (AP01) and (AP03) locations use O-ring gaskets at the two HPT case bosses

(Engines Post Reference 14, SB PW4G-112-75-30). See Figure 3 and 4.

C. Configuration 3 — Engines manufactured without the Modulated TVCA system or

Engines Post Reference 15, SB PW4G-112-72-84, Method 1. This system has a

duct AP114 in place of the TVCA valve, the AP01 duct, and the AP05 elbow. With

this configuration, you must use O-ring gaskets at the two HPT case bosses, (AP02)

and (AP04). The (AP114) and (AP03) locations use metering orifice plate and seal

assemblies (Engines Pre Reference 14, SB PW4G-112-75-30). The (AP01) and

(AP03) locations use O-ring gaskets at the two HPT case bosses (Engines Post

Reference 14, SB PW4G-112-75-30). See Figure 5.

3. It is permitted to use the optional entry port location for HPT stage 2 air seal temperature

measurements. Measure the HPT stage 2 air seal temperature through the EC inspection

port (previous step) with the use of a borescope to verify the thermocouple position is

on the HPT Stage 2 air seal outside diameter or remove the TCA Probe as specified in

Reference 7, Boeing 777 AMM Task 75-25-07-000-801. See Figure 7. See Reference

16., NDIP-1137, Section 3.

NOTE: Removal of the nuts from the TCA probe port studs when the engine is

hot without lubrication can result in stud breakage. Apply penetration oil to

the TCA Duct studs prior to removal per Reference 7, Boeing 777 AMM,

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 11

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Chapter/Section 70-00-00, SPOP 427. See Chapter/Section 70-00-00, Task

70-00-00-910-808-N00 for repair of broken bolts (SPOP 416).

4. Remove the main gearbox crank pad cover as specified in Reference 7, Boeing 777 AMM

Subtask 72-00-00-980-807.

5. Remove the starter as specified in Reference 7, Boeing 777 AMM Task 80-11-01-000-801.

6. Install the N2 rotor turning equipment as specified in Reference 7, Boeing 777 Aircraft

Maintenance Manual, Chapter/Section 72-00-00.

A. Install the rotator drive unit to the starter pad on the main gearbox.

B. Follow the instructions provided by the manufacturer for the assembly of the rotator kit.

C. Use the instruction manual provided by the manufacturer to operate the rotator.

7. Do Reference 16, Non-Destructive Inspection Procedure NDIP-1137. NDIP-1137 is

attached in the Appendix. See Figure 9, Sheets 1 and 2.

A. Provide the inspection result (Appendix 2 of the NDIP) to the Pratt & Whitney local

representative who will forward the results to the responsible customer technical

service contact.

B. If the mock up probe tip or EC probe tip liberates into the engine, every effort should

be used to remove the liberated material from the engine. If the mock probe tip or EC

probe tip is not accessible, it is acceptable to continue in service.

C. If the grind blend tip liberates, every effort should be used to remove the liberated

material from the engine. If the grind tip is not accessible it is acceptable to continue

in service if a visual borescope of the HPT stage 2 air seal OD cavity using the criteria

below is performed on reduced inspection interval not to exceed 60 cycles. If the

inspection is found acceptable, at this interval (60 cycles) the inspection interval

can be increased not to exceed 180 cycles. If the inspection is found acceptable at

this interval (180 cycles) the inspection interval can be increased not to exceed 360

cycles. At this 360 cycle interval this service bulletin EC NDIP 1137 Inspection should

be performed. If the inspections are found acceptable at this inspection interval,

then the HPT stage 2 air seal OD cavity and EC inspections should continue on

a repetitive 600 cycle interval.

HPT stage 2 air seal OD cavity inspection criteria as follows. See Figure 9, Sheet 3

for the specified surfaces.

Surface damage on the forward barrel fillet shown is not permitted, remove

engine in 5 cycles.

Missing material on the rear 1st stage side plate surface 1 or the forward air seal

knife edge surface 2 is not permitted, remove engine.

Missing coating of > 25% on the forward air seal knife edge surface 2 is not

permitted, remove engine in 5 cycles.

Nicks and dents greater than 0.010 inch (0.254 mm) depth in surface 4 and 5 is

not permitted, remove engine in 5 cycles.

Imbedded grind tip or dents in the forward T2V inner air seal honeycomb

surface 3 is not permitted, remove engine in 5 cycles.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 12

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
8. If HPT Stage 2 Air Seal indications are found greater than or equal to 1.2 volts peak

amplitude remove engine within five Flight Cycles (FC) (Reference 16, NDIP-1137 Step 6.1)

A. One isolated spike of greater than 1.2 volts after a 2nd EC inspection is performed

would be considered acceptable to continue in service if this Service Bulletin

inspection is performed on a reduced interval of 600 cycles. During that next 600

cycle interval if there are no isolated spikes of greater than 1.2 volts for two EC

inspections the engine could return to the 1200 cycle inspection interval.

9. If indications are within Reference 16, NDIP-1137 criteria the HPT Stage 2 Air Seal should

continue in service and be inspected on the repetitive inspection interval listed in this

Alert Service Bulletin.

10. Remove the rotator adapter from the gearbox crank pad location.

11. Install the gearbox crank pad cover as specified in Reference 7, Boeing 777 AMM Task

72-00-00-840-805.

12. Remove the N2 rotor turning equipment from the starter pad on the main gearbox.

13. Install the starter as specified in Reference 7, Boeing 777 AMM Subtask 80-11-01-400-801.

14. If removed, install the Upper Right TVCA Duct (AP01 or AP114) as specified in Reference 7,

Boeing 777 AMM, Task 75-25-05-400-818. The AP02 air duct is located at the two o’clock.

See Reference 14, Service Bulletin PW4G-112-75-30 to ensure a gasket is installed at the

HPT port in place of a metering orifice & seal assembly. See Figures 2 through 5.

15. If access to an optional HPT stage 2 vane cluster access was used, install the lower left

TVCA Duct (AP02) as specified in Reference 7, Boeing 777 AMM, Task 75-25-05-400-819.

This air duct is located at the four o’clock position. See Figure 6.

16. If removed, install TCA Probe as specified in Reference 7, Boeing 777 AMM, Task

75-25-07-400-801. See Figure 7.

17. Close the cowl doors as specified in Reference 7, Boeing 777 AMM, Chapter/Section

71-11-04.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 13

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
FOR PW4074D, PW4077D, PW4084D, PW4090, PW4090-3 ENGINES INSTALLED ON

AIRCRAFT

1. Open the cowl doors to gain access to the Turbine Vane Cooling Air (TVCA) Ducts. See

Reference 7, Boeing 777 Aircraft Maintenance Manual (AMM) Chapter/Section 71-11-04.

Allow engine to cool.

2. It is permitted to use the optional TVCA duct entry port location for Eddy Current (EC)

inspection access. Remove the TVCA Elbow (AP83) as specified in Reference 7, Boeing

AMM Task 75-25-05-000-824 or the upper right TVCA Duct AP114) as specified in

Reference 7, Boeing 777 AMM, Task 75-25-05-000-823. The AP83 elbow is attached to

the AP02 air duct and is located at the four o’clock location. See Figure 8.

NOTE: Removal of the bolts from the TVCA Duct access ports when the engine is

hot without lubrication can cause the bolts to break. Apply penetration oil

to the TCA Duct Bolts prior to removal per Reference 7, Boeing 777 AMM,

Chapter/Section 70-00-00, SPOP 427. See Chapter/Section 70-00-00, Task

70-00-00-910-808-N00 for repair of broken bolts (SPOP 416).

3. It is permitted to use the optional entry port location for HTP stage 2 air seal temperature

measurements. Measure the HPT stage 2 air seal temperature through the EC inspection

port (previous step) with the use of a borescope to verify the thermocouple position is on

the HPT stage 2 air seal OD or remove the TCA Probe as specified in Reference 7, Boeing

777 AMM Task 75-25-07-000-801. See Figure 7. See reference 16., NDIP 1137.

NOTE: Removal of the nuts from the TCA probe port studs when the engine is

hot without lubrication can result in stud breakage. Apply penetration oil to

the TCA Duct studs prior to removal per Reference 7, Boeing 777 AMM,

Chapter/Section 70-00-00, SPOP 427. See Chapter/Section 70-00-00, Task

70-00-00-910-808-N00 for repair of broken bolts (SPOP 416).

4. Remove the main gearbox crank pad cover as specified in Reference 7, Boeing 777 AMM

Subtask 72-00-00-980-807.

5. Remove the starter as specified in Reference 7, Boeing 777 AMM Task 80-11-01-000-801.

6. Install the N2 rotor turning equipment as specified in Reference 7, Boeing 777 Aircraft

Maintenance Manual, Chapter/Section 72-00-00.

A. Install the rotator drive unit to the starter pad on the main gearbox.

B. Follow the instructions provided by the manufacturer for the assembly of the rotator kit.

C. Use the instruction manual provided by the manufacturer to operate the rotator.

7. Do Reference 16, Non-Destructive Inspection Procedure NDIP-1137. NDIP-1137 is

attached in the Appendix. See Figure 9, Sheets 1 and 2.

A. Provide the inspection result (Appendix 2 of the NDIP) to the Pratt & Whitney local

representative who will forward the results to the responsible customer technical

service contact.

B. If the mock up probe tip or EC probe tip liberates into the engine, every effort should

be used to remove the liberated material from the engine. If the mock probe tip or EC

probe tip is not accessible, it is acceptable to continue in service.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 14

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
C. If the grind blend tip liberates, every effort should be used to remove the liberated

material from the engine. If the grind tip is not accessible it is acceptable to continue

in service if a visual borescope of the HPT stage 2 air seal OD cavity using the criteria

below is performed on reduced inspection interval not to exceed 60 cycles. If the

inspection is found acceptable, at this interval (60 cycles) the inspection interval

can be increased not to exceed 180 cycles. If the inspection is found acceptable at

this interval (180 cycles) the inspection interval can be increased not to exceed 360

cycles. At this 360 cycle interval this service bulletin EC NDIP 1137 Inspection should

be performed. If the inspections are found acceptable at this inspection interval,

then the HPT stage 2 air seal OD cavity and EC inspections should continue on

a repetitive 600 cycle interval.

HPT stage 2 air seal OD cavity inspection criteria as follows. See Figure 9, Sheet 3

for the specified surfaces.

Surface damage on the forward barrel fillet shown is not permitted, remove

engine in 5 cycles.

Missing material on the rear 1st stage side plate surface 1 or the forward air seal

knife edge surface 2 is not permitted, remove engine.

Missing coating of > 25% on the forward air seal knife edge surface 2 is not

permitted, remove engine in 5 cycles.

Nicks and dents greater than 0.010 inch (0.254 mm) depth in surface 4 and 5 is

not permitted, remove engine in 5 cycles.

Imbedded grind tip or dents in the forward T2V inner air seal honeycomb

surface 3 is not permitted, remove engine in 5 cycles.

8. If HPT Stage 2 Air Seal indications are found greater than or equal to 1.2 volts peak

amplitude remove engine within five Flight Cycles (FC) (Reference 16, NDIP-1137 Step 6.1)

A. One isolated spike of greater than 1.2 volts after a 2nd EC inspection is performed

would be considered acceptable to continue in service if this Service Bulletin

inspection is performed on a reduced interval of 600 cycles. During that next 600

cycle interval if there are no isolated spikes of greater than 1.2 volts for two EC

inspections the engine could return to the 1200 cycle inspection interval.

9. If indications are within Reference 16, NDIP-1137 criteria the HPT Stage 2 Air Seal should

continue in service and be inspected on the repetitive inspection interval listed in this

Alert Service Bulletin.

10. Remove the rotator adapter from the gearbox crank pad location.

11. Install the gearbox crank pad cover as specified in Reference 7, Boeing 777 AMM Task

72-00-00-840-805.

12. Remove the N2 rotor turning equipment from the starter pad on the main gearbox.

13. Install the starter as specified in Reference 7, Boeing 777 AMM Subtask 80-11-01-400-801.

14. If removed, install the TVCA elbow (AP83) as specified in Reference 7, Boeing 777 AMM,

Task 75-25-05-400-824. The AP83 elbow is attached to the AP02 air duct and is located

at the four o’clock position. See Figure 8.

NOTE: Reference 13, Service Bulletin PW4G-112-72-271 replaces the metering orifice

and seal assembly with a gasket.

15. If access to an optional High Pressure Turbine (HPT) 2nd stage vane cluster was

used, install the upper right TVCA Duct (AP114). The air duct is located at the two

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 15

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
o’clock position. Install the duct as specified in Reference 7, Boeing 777 AMM, Task

75-25-05-400-823. See Figure 5.

16. If removed, install TCA Probe as specified in Reference 7, Boeing 777 AMM, Task

75-25-07-400-801. See Figure 7.

17. Close the cowl doors as specified in Reference 7, Boeing 777 AMM, Chapter/Section

71-11-04.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 16

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
LOCATION OF THE PW4074, PW4077, PW4074D, PW4077D, PW4084D, PW4090,

AND PW4090-3 2ND STAGE HPT AIR SEAL ASSEMBLY

72-52-00

FIGURE 1

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 17

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
ENGINES WITH THE MODULATED TVCA SYSTEM (PRE REFERENCE 15, SB PW4G-112-72-84)

75-25-00

FIGURE 2

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 18

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
ENGINES WITHOUT THE MODULATED TVCA SYSTEM (POST REFERENCE

15, SB PW4G-112-72-84, METHOD 2)

75-25-00

FIGURE 3

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 19

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
TURBINE VANE COOLING AIR VALVE AND AP115 TUBE ASSEMBLY

75-25-00

FIGURE 4

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 20

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
ENGINES ORIGINALLY MANUFACTURED WITHOUT THE MODULATED TVCA SYSTEM

OR ENGINES POST REFERENCE 15, SB PW4G-112-72-84, METHOD 1

75-25-00

FIGURE 5

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 21

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
LOCATION OF THE TVCA DUCT (AP02) FOR THE PW4074 AND PW4077 ENGINES

75-25-00

FIGURE 6

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 22

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
LOCATION OF THE TURBINE COOLING AIR (TCA) PROBE

75-25-00

FIGURE 7

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 23

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
LOCATION OF THE TVCA DUCT (AP02) FOR THE PW4074D, PW4077D,

PW4084D, PW4090, AND PW4090-3 ENGINES

75-25-00

FIGURE 8

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 24

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
INSPECTION OF THE 2ND STAGE HPT AIR SEAL

FIGURE 9, SHEET 1

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 25

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
INSPECTION OF THE 2ND STAGE HPT AIR SEAL

FIGURE 9, SHEET 2

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 26

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
INSPECTION OF THE 2ND STAGE HPT AIR SEAL

FIGURE 9, SHEET 3

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 27

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Appendix

Parts Progression To Show the Changed Part in Relation to Other Parts

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 28

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
PROGRESSION OF THE PW4074 AND PW4077 2ND STAGE HPT AIR SEAL ASSEMBLY

CHART A

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 29

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
PROGRESSION OF THE PW4074D, PW4077D, PW4084D, PW4090, PW4090-3

2ND STAGE HPT AIR SEAL ASSEMBLY

CHART B

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 30

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
Added Data

Internal Reference Information

Revision No.

Reference

Document

Origination

Original EA11KCB91 BE/JEJ

1 EA11KCB91 BE/JEJ

2 EA11KCB91 BE/MJS

Number values shown in parentheses adjacent to U.S. values are International System of

units (SI) equivalents.

To calculate part life, include the hours and/or cycles since the part was made. Use the total

hours or cycles to calculate life limits that are the result of part modification, a part used in an

engine with different thrust, or for some other reason.

Inspection Procedures

NOTE: EXCEPT FOR WORK OR SUPPLIES TO BE PERFORMED OR FURNISHED BY

PRATT & WHITNEY, IT IS UNDERSTOOD THAT PRATT & WHITNEY DOES NOT

ENDORSE THE WORK PERFORMED BY THE COMPANY OR COMPANIES NAMED

HEREIN OR ANY OTHER COMPANY AND DOES NOT ACCEPT RESPONSIBILITY

TO ANY DEGREE FOR THE SELECTION OF SUCH COMPANY OR COMPANIES

FOR THE PERFORMANCE OF ANY WORK OR PROCUREMENT OF SUPPLIES.

Reference 16, Non-Destructive Inspection Procedure, NDIP-1137, PW4000-112” 2nd Stage

HPT Air Seal Forward Outer Diameter Eddy Current Inspection (On-Wing), follows.

l

December 3/12

PW4G-112-A72-330

REVISION NO. 2 - July 11/13 Page 31

UTC/P&W PROPRIETARY INFORMATION

Subject to the restrictions on the cover or first page.

Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3).
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

1

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

Applies to Models: PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090 and PW4090-3

P/N 54L041/54L043

NDIP 1137 Rev. C

WARNING

THIS DOCUMENT MAY CONTAIN INFORMATION SUBJECT TO THE INTERNATIONAL TRAFFIC IN ARMS REGULATION (ITAR) OR THE EXPORT ADMINISTRATION 

REGULATION (EAR) OF 1979. THIS INFORMATION MAY NOT BE EXPORTED, RELEASED, OR DISCLOSED TO FOREIGN NATIONALS OUTSIDE THE UNITED 

STATES WITHOUT FIRST COMPLYING WITH THE EXPORT LICENSE REQUIREMENTS OF THE INTERNATIONAL TRAFFIC IN ARMS REGULATION (ITAR) AND/OR 

THE EXPORT ADMINISTRATION REGULATION (EAR). A VIOLATION OF THE ITAR OR EAR MAY BE SUBJECT TO A PENALTY OF UP TO 10 YEARS 

IMPRISONMENT AND A FINE OF $1,000,000 UNDER 22 U.S.C 2778 OR SECTION 2410 OF THE EXPORT ADMINISTRATION ACT OF 1979. INCLUDE THIS NOTICE 

WITH ANY REPRODUCED PORTION OF THIS DOCUMENT.

RESTRICTION

PAGES OF THIS DOCUMENT MARKED WITH THE NOTICES SET FORTH BELOW CONTAIN CONTRACTOR COMPETITION SENSITIVE DATA AND/OR PRATT & 

WHITNEY PROPRIETARY DATA WHICH IS SUBMITTED IN CONFIDENCE. NO DISCLOSURE OR USE OF THIS INFORMATION IS PERMISSIBLE WITHOUT PRIOR 

WRITTEN CONSENT OF UNITED TECHNOLOGIES CORPORATION EXCEPT FOR OFFICIAL PURPOSES WITHIN THE U.S. GOVERNMENT.

DOCUMENT PROPERTY RIGHTS NOTICE

THIS DOCUMENT IS THE PROPERTY OF UNITED TECHNOLOGIES CORPORATION (UTC). YOU MAY NOT POSSESS, USE, COPY OR DISCLOSE THIS 

DOCUMENT OR ANY INFORMATION IN IT, FOR ANY PURPOSE, INCLUDING WITHOUT LIMITATION TO DESIGN, MANUFACTURE OR REPAIR PARTS, OR OBTAIN 

FAA OR OTHER GOVERNMENT APPROVAL TO DO SO, WITHOUT UTC’S EXPRESS WRITTEN PERMISSION. NEITHER RECEIPT NOR POSSESSION OF THIS 

DOCUMENT ALONE, FROM ANY SOURCE, CONSTITUTES SUCH PERMISSION. POSSESSION, USE, COPYRIGHT OR DISCLOSURE BY ANYONE WITHOUT UTC’S 

EXPRESS WRITTEN PERMISSION IS NOT AUTHORIZED AND MAY RESULT IN CRIMINAL AND OR CIVIL LIABILITY.

NOTICES

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

Approved By: Jonathan Sullivan, PL 3

Date: June 19, 2013
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

2

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

0.0 General

The objective of this procedure is to perform an eddy current (EC) inspection of the forward outer 

diameter radii of the HPT 1-2 Seal for possible indications. Since the part cannot be directly accessed 

(located inboard of the gas path) this is accomplished using a borescope and hand held remote wand 

eddy current probes. The probes enter the engine through a TCA manifold port on the HPT case, then 

through the 2nd stage vane transfer tube to then contact the seal in the desired area. The proper probe 

placement on the part surface is monitored via a 2.0 mm flexible borescope which is inserted through an 

adjacent 2nd vane transfer tube. The high pressure rotor is then rotatated via an engine rotator to effect 

scanning of the part. Figure 1 shows the cross section of the 1-2 seal, related parts and the zones of 

inspection.

FIGURE 1

0.0 Training and Certification

Formal instruction in eddy current testing:

0.1.1. Inspection personnel shall be certified to ASNT Level II, NAS 410 Level II, ATA Spec 105 Level II 

or equivalent qualification in eddy current method. 

Required for this procedure:

0.1.2. Approximately two days of instruction and familiarization with test equipment, probes and this 

inspection technique. 

0.1.3. Inspector shall demonstrate Probability of Detection (POD) flaw capability on the POD (EDM 

notched) test part. The 90% probability of detection, 95% confidence level maximum allowable 

flaw size shall be 0.012” notch depth.

1-2 Seal

OD Inspection 

Zone

2nd Vane Assy.

Transfer 

tube exit

Honeycomb

Aft

Fwd

Transfer 

tube elbow
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

3

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

0.1.4. Inspector recertification is required if more than 4 months elapse without having performed an 

engine inspection or completed training/refresher training. Recertification will require an 

approximately one day refresher course given by a Pratt & Whitney approved instructor. 

1.0 Equipment Required

1.1. Inspection Kit, PWA107958 consisting of the following:

1.1.1. EC Probe, PWA 107921** (US-2823, red stripe on handle), Figure 2

1.1.2. EC Mock-Up (dummy) Probe, 71993 (green stripe on handle)

1.1.3. Cleaning Probe, 71992, (white stripe on handle)

1.1.4. Cleaning Brush, P/N CB-2010, Figure 11, 12

1.1.5. Cleaning Brush cable clamp, P/N 74096

1.1.6. EC Probe Cable, US–94032

1.1.7. Calibration Standard, PWA107922**, Figure 5

1.1.8. Probe Tip Holder, 71984, Figure 4

1.1.9 Eddy Current Instrument, UniWest US-454, Figure 3, with accessory compact flash memory card

1.1.10 60 cc Syringe & plastic tube*

1.1.11 Fluke 16 Multi-meter and flexible thermocouple (or equivalent)

1.1.12 Probe to HPT Case Holder, 71987, Figure 19

1.1.13 Extension cord*

1.1.14 Power Strip* 

1.1.15 Flashlight* 

1.1.16 Clip Board* 

1.1.17 Misc. hand tools (allen wrench set, needlenose pliers, wire stripper/cutters, screw driver, duct 

tape, electrical tape, tie wraps) (*)

1.1.18 Machida blend tool kit, BT-4000PW, consisting of:

power supply, foot pedal control, motor handle, blending guide tube, grinding bits, collet, 

misc. tools in pouch, tool holder

1.1.19 Custom case for items 1.1.1 through 1.1.18.

* - Common tools/items can use an equivalent substitute

** - PWA tools can be replaced by latest revision letter tool

1.2 Additional Equipment Required:

1.2.1 Machida Video Scope, consisting of Model 7-6060, integrated processor/light unit and VSC-2-

86, 2.0 mm diameter, flexible videoscope. The 7-6060 includes AC power cable, video cable, 2 

GB SD storage card, reference card, users manual and roll around case, see Figure 24. 

Equivalent borescope/videoscope may be used (note: maximum borescope diameter that will fit 

through 2nd Vane transfer tube is 2.5 mm). 

1.2.2 Machida Engine Rotator Kit, MA-TT-70 includes: drive motor, 12” offset drive adapter, DR-00 

drive adapter, TT-70-A controller, AC power cable, unit to motor cable, allen wrenches, spare 10-

32 screws, user manual, roll around case, see Figure 25. Also in case are AD-03 adapter plate

and DR-03 drive adapter. An equivalent rotator may be used but must be adaptable to engine 

starter location and capable of turning engine at constant one rpm (within 5%).
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

4

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

2.0 EC Calibration

2.1. Connect the PWA107921 probe to the probe cable and US-454 EC instrument (see Kit 1.1.1, 1.1.6, Figure 

2). . 

2.2. Power on the US-454 EC instrument and allow it to warm up for a period of 5 minutes, or as specified in the 

instrument user manual (see Kit 1.1.9, Figure 3).

FIGURE 2

PWA107921 Eddy Current Probe

NOTE: Once set, the detailed instrument settings can be loaded into the unit’s memory via 

the “Save Settings” function. This will help the operators reset the unit to the desired 

values. All parameters shall be verified before proceeding with the calibration. 

NOTE: To ensure all parameters are properly set, the inspector can recall the instrument 

default settings by selecting “ENTER SETUP” then selecting “LOAD DEFAULTS” and 

pressing enter. If this is done, each and every parameter identified below must be manually 

entered. 

FIGURE 3

Eddy Current instrument (UniWest US-454)
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

5

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

2.3. Set up US-454 EC instrument to the following initial settings:

2.3.1. FREQ 1: 3 MHz 

2.3.2. F1 GAIN: 66 dB

2.3.3. F1 ROT: 90 degrees (initial phase angle) 

2.3.4. DRIVE: HIGH (probe drive)

2.3.5. LP FLT: 50 Hz (low pass filter)

2.3.6. HP FLT: 2 Hz. (High pass filter)

2.3.7. CHART: ON

2.3.8. EC DISP (Screen Mode): I-PLANE (Impedance plane)

Settings below are under ‘Enter Setup’ sub-menu

2.3.9. Sample Rate: 504 samples/sec

2.3.10. O-scope sweep rate: 1 sec/div

2.3.11. O-scope trigger source: free run

2.3.12. Report Files: BMP + TXT

2.3.13. Circular Buffer: No

2.3.14. Rundown Battery Monitor: Off (white letters on red background), then ‘cancel’.

2.4. Install probe tip in probe tip holder (71984) as shown in Figure 4. The back of the probe tip (with white line) 

should be flat against the cavity in the probe holder. Tighten the thumb screw sufficiently to hold the probe 

tip firmly but do not over tighten (see Kit 1.1.8, Figure 4).

 

FIGURE 4

Probe in probe tip holder for calibration

2.5. Place the probe/tip holder on the PWA107922 gauge standard and line it up approximately 1⁄4 inch from the 

left end (as marked) while facing the front of the standard (Figure 5). Push “null” while holding the probe in 

contact with the OD radius of the calibration standard (see Kit 1.1.8, Figure 5).

2.6 Scan the probe to the right at a constant speed of approximately 1.4 inches per second towards the EDM 

calibration notch ‘A’, making sure to keep the probe tip holder in square contact with the standard. Observe 

the indication in the impedance plane display and adjust the rotation (phase angle) to vertical as shown in 

Figure 6. The cable end of the probe should not be held; it should be allowed to slide smoothly 

along the bench/table. This will help avoid signal noise.
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

6

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 5

PWA107922 calibration standard consists of actual section of seal with EDM notch

2.7 Once phase angle is set, rotate knob to “EC Display”, push “Enter” and change to “O-Scope”. Then briefly 

push the “Display|on/off” button to switch to horizontal sweep oscilloscope display, as in Figure 7. 

2.8 Rotate the knob so that “Save Report” is highlighted on the instrument screen (do not push enter yet). 

2.9 With the probe holder lined up to left as in 2.5, push the “Erase” button and then start to scan the probe 

steadily to the right side and past the EDM notch A. Press “Enter”, and then press “Enter” again to access 

report file naming function. Enter a convenient single character for a file name and this push “Enter”.

2.10 Rotate the knob to “Recall Report” and press “Enter”. Use scroll knob to highlight the file name just saved 

and press “Enter” to display the scan. Scan speed can be estimated as follows: since the horizontal sweep 

rate of the instrument is set to 1 second/division, the scan, at constant speed, should take between 5 and 6

seconds to scan reach the notch signal (from the start of the scan), see Figure 7. 

NOTE: It is important to scan at the proper speed (and especially not too fast). Scanning too fast 

can result in significantly lower amplitude for the notch leading to excessively high gain levels. 

Calibration gain should not exceed 72 dB; if it does, re-check scan speed.

2.11 If scan speed is acceptable, observe the notch signal peak to peak amplitude (count screen divisions, each 

division is divided into 5 subdivisions or 0.2 divisions each dot). If necessary, adjust gain and repeat 2.8 -

2.11 to produce an EC signal equal in amplitude to the set up card to within +/- 0.4 divisions. See Figure 7

for typical trace over the gage standard. Note the slight increase in noise once the probe starts moving; this 

is where time of scan starts.

OD Radius

forward flange

Scan start 

position
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

7

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 6

Phase angle set to vertical on calibration notch.

FIGURE 7

O-Scope display of EDM notch signal on calibration standard.

2.12 Fill in the required information on a fresh Eddy Current Inspection Data Sheet (Appendix 1), noting the 

calibration notch ‘A’ response amplitude, the phase angle, the calibration gain, and the inspection (total) 

gain settings. Also note the seal temperature, part number, serial number and engine cycles/hours (if 

available) on the inspection sheet..

2.13 Rotate knob to “EC Display”, push “Enter” and change back to “I-Plane” display prior to collecting engine 

data. This step is required to ensure phase angle data is collected during inspection.

scan start

notch signal

between 5 

and 6 seconds

amplitude 

(peak to peak)
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

8

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

2.14 Add 12 dB of gain to the calibration gain prior to the inspection. 

2.15 The Calibration should be re-performed if the inspection has been interrupted for more than 30 minutes

or instrument loses power (shuts off) before inspection and post-inspection calibration are completed.

Remove probe tip holder, 71984, before using probe in engine.

3 Engine Access Precautions and Procedure

WARNING: Follow site protocols concerning clothing and procedures for entering engine nacelle as well as rules 

on making electrical connections. Refer to AMM 78-31-00 for tasks and safety precautions related 

to the engine thrust reverser system.

NOTE: Local management may contact the local P&W Representative to arrange for an on-site protocols 

briefing of special engine access rules.

3.1 Engine must be cool or ambient. If necessary, forced air cooling or heating may be performed (also see 3.3)

Gain entry to the inspection area by having the nacelle fully open. Optimal access to inspection location is 

via HPT case TCA manifold port located at approximately 4:00 on the case (viewed aft looking forward) on all 

affected PW4000 engine models (see title page). HPT case ports at 2:00 and 10:00 are optional choices for 

access if 4:00 port cannot be used (see Accomplishment section in the Service Bulletin).

3.2.1 Locate a suitable ladder or scaffold to allow one person comfortable access to the TCA port 

location(s) being utilized. Borescope and EC instrument should be positioned so probe and 

borescope can comfortably reach the HPT case port.

3.3 The 1-2 Seal temperature is measured via flexible thermocouple (see Kit 1.1.11) through the 2nd Vane 

transfer tube (same location as utilized for EC inspection (see Figure 10). The borescope must be used to 

visually verify that thermocouple tip is touching the 1-2 seal. An optional alternative to the 2nd Vane transfer 

tube is the TCA temperature probe location (adjacent to 10:00 TCA manifold port, see Figure 8). The TCA 

temperature probe is removed and then the flexible thermocouple is inserted (it should go in for approximately 

9 inches before the tip reaches the seal, visual confirmation is not required). Allow reading to stabilize and 

record temperature on inspection sheet (Appendix 1).

NOTE: Metal temperature must be no greater than 110 F (44 C) before inspection can take place

or damage to EC probe may result.

FIGURE 8

Alternate location for taking seal temperature

3.4 Entry of Inspectors and Equipment into Engine for Inspection
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

9

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

3.4.1 Set up the Engine Rotator control unit by connecting power cable, motor cable and controller 

(see Kit 1.2.2, Figure 25).

3.4.2 Remove the engine air starter (at approximately 5:30, aft looking forward) per the 

accomplishment section of Service Bulletin.

3.4.2.1 Set up the Engine Rotator and connect drive mechanism to the starter adapter plate per 

the accomplishment section of service bulletin. Also install the rotator gearbox adapter 

as shown in Figure 9. The adapter is only used to keep track of part rotation (see 4.1.2).

NOTE: Verify that the engine rotor is smoothly turning the seal in CW direction when aft looking 

forward (the OD surface of seal moving away from you on the borescope monitor). Line 

up the index marks on the rotator gearbox adapter (by turning rotor as needed), Figure 

9. The woodruff key slot should be positioned at 12:00 for convenience in keeping track 

of rotations. The slot will rotate 3⁄4 of a revolution for one complete rotation of the 

N2 rotor. Speed control on engine rotator should be adjusted so that 3/4 

revolution of key slot is completed in approximately 1 minute (plus or minus 5 

seconds). Rotate the engine slowly for 2 revolutions of the woodruff key and look for 

any debris or deposits on the seal inspection area that might cause problems with probe 

contact. If the inspector observes any unusual condition or debris, borescope 

photographs can be taken and forwarded to Pratt & Whitney representative for 

consultation. See Quick Reference card in kit for instructions on how to take borescope 

photos (see Kit 1.2.1, Figure 24).

FIGURE 9

3.5 Power up the borescope and carefully insert the borescope into the 2nd Vane transfer tube entrance 

exposed near the lower edge of case port (prior to Figures 10 & 11 which show EC probe inserted at this 

location). Look for any debris, damage or edge obstruction in tube or at tube exit that might obstruct

passage of the EC probe wand. Carefully push the borescope tip past the transfer tube exit until the white 

tape on borescope wand is approximately even with tube entrance. Articulate the stalk as necessary to 

view the 1-2 Seal. 

Woodruff key slot 12:00

11:00

6:00
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

10

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

 

FIGURE 10

FIGURE 11

3.6 Carefully remove the borescope stalk from this 2nd Vane tube and re-insert it in the transfer tube 

adjacent to (and above) the full view tube. It is slightly behind the HPT case outer wall but the 

borescope can easily be maneuvered to gain access. See Figure 10,11.

3.7 Prior to insertion of an actual eddy current probe, the ‘Mock-Up’ Probe, 71933, should be inserted to test 

transfer tube clearance (see Kit 1.1.2). 

3.8 Carefully insert the Mock-Up probe tip in the 2nd Vane transfer tube (fully visible tube entrance 

toward the lower edge of the port that was previously checked for debris in 3.5). The white line on 

the tip should be facing down (towards the convex side of transfer tube entrance, see Figure 11). 

Some resistance will be felt as the probe is pushed past the transfer tube elbow and tube exit (more 

resistance than borescope stalk). Be careful not to buckle the yellow tube; use two fingers to 

support it while pushing it through. Do not use excessive force; it may help to rotate the probe 

handle a bit from side to side to help ingress and using fingers to support the yellow stalk as in 

HPT Case Port

at 4:00 (AP02) 

position, aft 

looking forward

2nd Vane transfer 

tube entry location

for borescope

(partially hidden 

under case)

black mark for 

insertion depth

transfer tube 

entrance for 

EC probe

convex side of opening
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

11

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

Figure 12. Insert probe until the edge of black marking on the probe stalk is even with the transfer 

tube entrance (Figures 10,11).

3.9 Observe the probe tip by moving the borescope stalk as needed. The probe tip should be positioned in 

the groove as described in Figures 13 and 14. When tip is in correct position, rotate engine for two full 

rotations of the gearbox adapter key slot. Observe the probe wand/tip on the borescope screen and 

look for any signs of probe movement as the seal rotates. The probe should not show any noticeable 

movement which could cause lift-off and false calls. If such movement is present remove probe and 

investigate OD groove with borescope to try and determine if any surface debris is present that might 

cause the problem. If probe movement cannot be remedied, make a note of this on the inspection data 

sheet. After the first 3 – 5 seconds, the engine should rotate smoothly and consistently. If this cannot 

be achieved, make note if it on the inspection sheet.

NOTE: Be mindful that if the borescope wand is touching the seal the entire display may appear to 

move (not just the probe). If the vane honeycomb appears to be moving at same time as probe, this 

is the reason. If this occurs the it may help to reposition the borescope and check again.

FIGURE 12
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

12

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 13

FIGURE 14

Cross section showing proper side to side placement of probe tip

Remove the mock-up probe by gently pulling the handle away from the HPT case but still aligned with 

the transfer tube (avoid excessive bending of probe wand). Some resistance will be felt as the probe tip 

negotiates the transfer tube elbow. If the probe feels to be stuck, try to get a view with the borescope of 

the problem. If necessary, push probe back in to inspection position and push plunger end to extend 

vane honeycomb

Intersection of groove 

and cylindrical surface

right side of probe tip

0.020” (0.51 mm)

Seal OD surface

inspection zone

Fwd

Aft

knife edge seal

Probe tip radius sits 

evenly in groove
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

13

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

the coil, (see Figure 16) and rotate tip to an alternate position and then let tip retract (let off plunger). 

Try and extract probe again while preventing plunger spring from compressing (do not let tip selfextend). Once probe is extracted, re-inspect tube with borescope to determine cause of problem. DO 

NOT USE EXCESSIVE FORCE TO REMOVE PROBE OR TIP MAY PULL OFF AND DROP IN 

ENGINE. Carefully inspect the transfer tube exit for signs of excess casting flash (lip) or excessively 

rough casting surface in elbow that may impede probe tip movement. Also look for signs of transfer 

tube neck down at joint between tube and elbow (see Figure 15). If any of these conditions are

observed, it will be necessary to de-burr/blend this area using the procedure in Appendix 2. After 

blending, try mock-up probe again and verify it can be inserted and extracted without issue. Fill in 

Yes/No at bottom of inspection data sheet (Appendix 1) next to “Blending Required”.

NOTE: If EC probe tip or Mock Up probe tip liberates from probe stalk during withdrawal from 

engine or if a grinding tip (during transfer tube blending) separates from flexible shaft and

cannot be recovered from inside engine, see Service Bulletin for disposition.

FIGURE 15

 

FIGURE 16

Borescope view showing example of transfer 

tube/elbow joint with restricted area, preventing 

probe tip from passing through.

extended probe tip
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

14

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

3.10 Seal cleaning procedure

Note: Water is the primary solution to be used for seal cleaning but in some cases it may be 

necessary to use a stronger solvent. Isopropyl Alcohol and Acetone are permissible if water will not 

remove adhered debris on seal. It is recommended that no more than 120 cc of either solvent be 

introduced into engine. Either solvent should only be used when seal temperature is at or below 

110°F (44°C). The syringe and plastic tube are resistant to these chemicals.

3.10.1 Fill the 60 cc syringe with clean water (see Kit 1.1.10). Insert the plastic tube end through 

the vane transfer tube and position it so the black mark on the tube is even with the transfer 

tube entrance.

Note: When seal metal temperature has dropped to 200°F (93°C), it is permissible to initiate 

cleaning of seal with water. It is not recommended to use alcohol or acetone until 

temperature has dropped to 110 F (44 C). 

3.10.2 While rotating the engine, spray water into the seal area by slowly pushing the syringe 

plunger. Try to push uniformly such that the entire seal OD is wet in the inspection zone 

(avoid spraying directly on borescope tip). If necessary, spray another 60 cc of water to 

ensure the whole inspection zone is wet. Use the borescope to view the nozzle tip to ensure 

that water is spraying onto the OD groove feature (inspection zone).

3.10.3 Remove syringe/plastic tube and wait 10 minutes.

3.10.4 Insert the brush/cable into the Cleaning Probe, 71992 (see Kit 1.1.4, 1.1.3), and secure the 

cable end to the cable clamp on the probe handle (tighten white knob) see Figure 17 (also 

see Kit 1.1.5).

3.10.5 Insert the Cleaning Probe with brush and position the brush so it is in contact and centered 

in the OD groove on the seal, see Figure 18. Use borescope to view brush position.

NOTE: Use a dark colored permanent marker to blacken approximately the last inch (25 mm) of the 

probe stalk (Figure 17). This will help reduce light reflection from the probe and prevent the 

borescope from auto-dimming. It may also help to change from ‘auto’ to ‘max’ (8) on the 

borescope light control and to change ‘gain’ to ‘on’.

3.10.6 Rotate the engine for 3 key slot revolutions while observing the brush through the 

borescope to verify it stays in contact with the part. Remove cleaning probe/brush when 

complete.

 

FIGURE 17

Cleaning Brush

Use dark permanent

marker to color end of 

probe stalk to reduce 

light reflection

(approximately 1 inch).

brush cable

cable clamp
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

15

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 18

Cleaning Brush in position (borescope view)

3.10.7 Remove brush from Cleaning Probe and then re-insert the probe handle/wand, 71992, 

(without the brush) and position the end of the yellow tube so it sits in the center of the OD 

groove.

3.10.8 Apply shop air to the cleaning probe handle to force air through the tube. Rotate the engine 

for 3 key slot revolutions while blowing compressed air through the tube. This will help 

remove any loose debris in the inspection zone.

 4.0 Inspection

4.1 On the PWA107921 Eddy Current probe, align the probe tip with the black dot on the (yellow) 

probe wand, see Figure 16. The tip can be rotated by pushing in probe plunger and rotating, 

but be careful to rotate no more than 180 degrees in either direction or coil signal wires may 

twist inside handle and break (resulting in a dead probe). Carefully insert the calibrated Eddy 

Current probe tip into the transfer tube with the white line on the probe tip facing the convex 

side of the tube (facing down in Figure 10). Failure to do so may result in probe tip getting 

stuck in tube! Some resistance will be felt as the probe is pushed past the transfer tube 

elbow and elbow exit (more resistance than borescope stalk). Be careful not to buckle the 

yellow tube; use fingers to support it while pushing it through (Figure 12). Do not use excessive 

force; it may help to rotate the probe handle a bit from side to side to help ingress. Once fully 

inserted, it is also permissible to push in plunger end of handle to extend probe tip to help 

positioning tip (it is spring loaded, also see Figure 16). Insert probe until the black marking on 

the probe stalk is even with the transfer tube entrance (Figure 11).

4.2 Articulate the borescope as necessary to view the probe tip. Adjust probe tip position, if 

necessary, to ensure the tip is in full contact and is properly centered in the OD radius. 

This step is critical to a good inspection. When viewed with vane honeycomb on right side 

of borescope monitor screen, the right edge of the probe tip should be close to the intersection 
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

16

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

of the OD groove with the flat area (aft side of groove) as shown in Figure 13. Figure 14 shows 

a scale drawing of the seal cross section and how the probe tip should fit in the OD groove. 

NOTE: Be careful that the borescope tip does not get under the probe stalk and push the probe up 

off the part surface. 

NOTE: Use a dark colored permanent marker to blacken approximately the last inch (25 mm) of the probe 

stalk (Figure 17). This will help reduce light reflection from the probe and prevent the borescope 

from auto-dimming. It may also help to change from ‘auto’ to ‘max’ (8) on the borescope light 

control and to change ‘gain’ to ‘on’.

4.3 Null the probe by pressing the ‘Null’ button on US-454 EC instrument. Double check that 12 dB of 

gain was added to the calibration gain. Also check that Strip Chart and Impedance Plane are being 

displayed on US-454 display.

4.4 Observe signal trace on eddy current instrument screen. If it appears unusually flat (i.e. no baseline 

noise), double check to make sure tip is in proper contact with the OD radius and probe cable 

connections are correct and working. If proper probe tip contact cannot be achieved, try a different 

probe from the kit.

4.5 Once the probe is satisfactorily positioned, install the Probe to Case Holder, 71987 (see Kit 1.1.12, 

Figure 19). This device keeps the probe steady and prevents signal noise due to movement of probe 

handle. 

NOTE: Prior to starting inspection scan, pull the borescope back away from probe tip by 

approximately 1.5 – 2.0 inches (40 – 50 mm) to avoid borescope tip bumping into probe 

during engine rotation (which can cause false call signals)

NOTE: the inspector should not hold the probe handle during the inspection scan.
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

17

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 19

4.6 Rotate engine clockwise (aft looking forward) with the Engine Rotator, as required to align key 

slot at the 11:00 location on gearbox adapter (Figure 9). 

4.7 Prepare the US-454 eddy current instrument for recording the engine scan data by displaying the 

selection menu on the right side if the screen (push enter button once if menu is not displayed). 

Scroll as necessary to find ‘Save Data’ on the menu (Figure 20) and leave it highlighted (do not 

hit enter). Turn on the engine rotator and when key slot reaches the 12:00 position, push the 

‘Erase’ button on the US-454 to start scan data collection (see Figure 3). The erase button clears 

the instrument buffer so that all data collected will be from this point in time. 

Note: the engine should be up to one rpm scan speed before the data collection begins.

4.8 The inspector shall monitor the instrument screen for signals exceeding the rejection threshold 

criteria. When the key slot has completed 360 degrees (reaches 12:00 again), push ‘Enter’ 

button on US-454 Eddy Current Instrument (it is critical to make sure the scan overlaps the 

start position to ensure no portion of seal is missed). This will stop data collection. Push 

‘Enter’ once more and the instrument will then be ready for naming of the scan data file as shown 

in Figure 20. The scan data file must be named (with engine serial number and dash number for 

scan 1, 2 , etc.) and saved on the instrument (see 4.9). 

Probe to Case holder sits in 

lower half of boss. Hand 

tighten red thumb screw, 

then close and tighten 

probe handle clamps.
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

18

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

 Note: file name is limited to 8 characters

FIGURE 20

4.9 Rotate the scroll knob to select the first letter/number in the file name. Then use the F2 key to 

move the cursor to next location. Rotate scroll knob until next desired digit is shown, push F2 

key, etc. The F1 key can be used to back space in case of error. Once the file name is 

completed, push “Enter” enter and the file name should appear highlighted. 

4.10 All data must be reviewed by inspector. This is done by choosing ‘Recall Data’ from the screen 

menu and then selecting the file from the list of saved files (using scroll knob). The data review 

screen will appear as shown in Figure 21. The electronic strip chart of Y signal component for 

entire scan is on the left while a zoomed up portion of this signal between the green cursor lines 

is on the right. The operator shall set the controls for the zoomed portion by hitting ‘Enter’ and 

then adjusting ‘Frame Length’ to minimum value, ‘Scroll Step’ to 15%, ‘Chart Display’ to Y and 

sensitivity to 0.5 v/div, see Figure 22. After setting these parameters push the ‘cancel’ button. 

The inspector may use other sensitivity settings as convenient during data analysis (data does 

not change, only voltage scale on instrument changes).

4.11 Use the scroll knob to move the green cursor lines through the scan and record positive or 

negative indications equal to or above 1.2 volts peak amplitude. Be sure and record data 

file name on data sheet. In addition, if only a single (1) peak/event exceeds 1.2 volts after 

the re-inspection the seal is not rejectable (see 4.12 and Figure 23). However, if this 

situation occurs, the seal will need re-inspection at a reduced interval per the Service 

Bulletin. Depending on the spacing between indications, frame length may need to be raised or 

lowered to ensure the entire signal in question (and no more) is within the green frame lines. 

Note: if more than 6 signals are above reject threshold, record only the 6 of highest amplitude and 

note “numerous rejectable indications” on the inspection data sheet (Appendix 1). 

cursor control for 

moving to next letter 

(or backspace)

file naming
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

19

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 21

FIGURE 22

Green lines (cursor) 

define portion of 

scan to be zoomed 

on right

Largest Positive and Negative 

Peak Amplitude within 

zoomed area of signal

possible 

indications

phase 

information
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

20

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 23

4.12 If rejectable indications are found, the inspection should be repeated one time (repeat 

sections 2 and 4). If the data appears to have other anomalies, rectify problem and reinspect. EC probe can be removed from the 2nd Vane after all data are reviewed. If debris 

is suspect as cause of rejection it is permissible to repeat cleaning procedure, 3.11.

NOTE: If rejectable indications (equal to or greater than plus or minus 1.2 volts peak 

amplitude) are observed, repeat inspection (a spare probe may be used) per sections 2 

and 4. If 2nd scan is acceptable (see single peak exception in 4.11), the seal is

acceptable. Both scans must be recorded. If debris on seal surface is suspect, repeat 

cleaning procedure before re-scan.

4.13 At end of work shift, all scan files on the EC instrument compact flash storage card must be 

backed up to an external storage device (i.e. laptop computer). This is done by shutting off 

Single ‘event’ above 

reject threshold

Although both 

positive and 

negative peaks are 

above threshold, 

this example shows 

a single event and 

counts as a single 

peak above reject 

Example showing two 

separate peaks above 

reject threshold

It is uncertain if these 

peaks result from a 

single or double 

indication since they 

are clearly separated 

in time. As such, they 

would be considered 

as two peaks above 

reject threshold
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

21

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

EC instrument, removing the card and, using a suitable card reader, copy the data files for 

each engine to a folder name with engine serial number. 

5.1 Post-inspection probe calibration check.

5.1.1 Reinstall probe shoe, 71984, on probe tip, bring gain down 12 dB (to original calibration gain) and 

check probe calibration on notch A. It should read within 15 % of original calibration amplitude. If 

these criteria cannot be met, re-inspect OD radius per section 4.0.

5.1.2 The final determination of all reportable indications is based on the accept / reject criteria in 

section 6.0.

6.0 Analysis and Reporting of Inspection Data

6.1 Indications equal to or greater than 1.2 volts peak amplitude (positive or negative) are 

rejectable and should be recorded on Inspection Data Sheet (Appendix 1). 

7.0 Reporting / Disposition 

7.1 Provide inspection results (Appendix 1 data sheets) to the local Pratt & Whitney Field 

Representative (electronic or hard copies).

7.2 Electronic copies of the eddy current data files (as saved on the compact flash storage card) 

and a copy of the corresponding data sheet (Appendix 1) should be given/transferred to the 

local Pratt & Whitney Field Representative who will then forward these documents to Pratt & 

Whitney Materials & Process Engineering, Non-Destructive Evaluation group.

FIGURE 24

Borescope Kit
NDIP 1137

Technique Sheet for PW4000-112” HPT 1-2 Seal NDI (On-wing application)

22

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

FIGURE 25

Engine Rotator Kit
 APPENDIX 1 NDIP 1137

PW4000-112” HPT 1-2 Seal On-Wing EC Inspection ECI of OD Forward Radius

Engine Models: PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3

Probe P/N ______________ Probe S/N __________________ Seal Temp.:__________ Date: _______________

Seal P/N ____________ Seal S/N ____________ Engine Cycles/Hrs ___________ Seal Cycles/Hrs ____________ 

Aircraft Number _______________ Engine S/N ______________ Engine Position ______ Inspector: ___________

Calibration Gain:________ @ notch ‘A’ amplitude per cal card, Gauge Standard S/N: _________ , Phase Angle: ________

Total Gain: _______ (+12 dB), set Y sensitivity to 0.5 v/div, US-454 Data File Name: _________________________ 

Indication # Time (in scan) Peak Amplitude + or - (volts) Comments

Vane Blending Required ______ (yes/no)
NDIP 1137

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

24

APPENDIX 2

Special Blending Procedure (Rev08)

PW4000-112” 2nd Stage HPT Vane Transfer Tube Air Passage Tube

Engine Models: PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3

Subject: 

This blend procedure is used to provide clearance for the eddy current probe by removing material from the 

T2V transfer tube air passage. This tube allows access for eddy current inspection and if it is distorted or if 

cast portion has an excessively rough surface or has a lip of excess cast flash material at the transfer tube exit, 

the eddy current probe may not be able to pass through. 

1. Equipment: 

2.0 mm Machida Video Borescope (see Kit 1.2.1, Figure 24)

Machida blend tool kit, BT-4000PW (see Kit 1.1.18, Figure A)

FIGURE A

Machida Blend Tool
NDIP 1137

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

25

2. Inspection Preparation: 

2.1. Insert the 2 mm borescope into the HPT 2nd stage vane transfer tube entrance port and inspect the 

passage for distortion,/bulging material (Figure B ) or for excessive casting flash (Figure C).

FIGURE B

Distorted bulging material is below the arrows (above)

FIGURE C 

Lip of flashing material is between the arrows (above)

2.2. If distortion or bulging or rough casting surface is visual (Figure B, C) remove the bore scope, 

assemble the blend equipment per section 3.0 and follow the blend procedure per section 4.0 for the 

T2V air tube passage distortion/bulging

Note: a small amount of distortion is enough to impede the ECI probe

2.3. If no distortion, bulging or rough casting surface is present inside the T2V transfer tube air passage, and 

then push the scope thru the tube until the inner passage or exit opening is visible. Verify and/or Inspect 
NDIP 1137

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

26

exit opening for evidence of a lip of casting flash material at the “U” shaped portion (left side) of the 

opening (Figure C). If flash lip is evident, assemble the blend equipment per section 3.0 and follow the 

blend procedure per section 5.0 for excess casting flash.

Note a small amount of flashing is enough to impede the ECI probe

Note: Some vanes have excess flash material only at the bottom of the “U” shaped opening that 

must be removed, while others may have additional excess material on the sides of the “U” that 

must also be removed

3. Assembly of Blend Equiptment

3.1. Assemble the blend equipment. See Fig. A. and refer to instruction manual. Make sure control box power 

switch is in the off position, the direction of rotation switch is in the forward position, and speed adjustment is in the 

min position. Attach the foot pedal, put switch in foot position, move 110/220 voltage selector switch to the 

applicable supply voltage, and connect the handle power cord to the control box. NOTE: Always use the foot 

pedal. Unlock the collet on the handle by rotating the collet release ring. Insert the blend tool drive cable thru the 

Teflon tube and attach to handle by inserting the drive cable end of cone-shaped blend tool (red color on shaft) 

into the collar, leaving a gap of approximately 1/8” (3 mm) between Teflon tube end and blend tip. Lock the collet 

by rotating the collet release ring. Finger tighten the hose clamp that secures the Teflon tube to handle. Turn the 

power switch to the on position, and depress foot pedal to test the rotation of blend tool.

4. Blend Procedure for distorted/bulged T2V transfer tube air passage

4.1. If there is distorted, bulging material, or a rough casting surface to be blended, partially insert the blend 

tool first into the vane transfer tube opening, and then insert the bore scope slightly behind the blend tool. 

Push the borescope and blend tool together thru the opening, viewing the blend tool ahead of the 

borescope on the borescope monitor. Position the cone shaped blend tip slightly in front of the bulged, 

distorted material or rough casting surface. Keep a safe distance between the borescope and blend tool 

tip. See Figure D.

FIGURE D 

Blending tip in correct position while blending bulging material
NDIP 1137

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

27

4.2. Always blend at a slow speed. Always start with the smallest diameter blend tip and gradually change to 

a larger diameter tip as needed to remove additional material. The shaft of the blend tool may fail if 

the blend tip gets jammed. Use only the forward motor direction. Blend tool shaft failure may result 

from using reverse motor directions.

NOTE: Use caution not to jam blend tip in bulge area of vane transfer tube. If the blend tip liberates, 

every effort should be used to remove the liberated material. If the liberated material is not 

recoverable see the Service Bulletin accomplishment section for continue in service direction.

4.3. Turn motor switch to on position. With blend tip slightly before bulge location, press foot pedal and 

gently move cone blend tool in and out slightly to remove excess bulging material. It is possible the 

transfer tube wall becomes slightly compromised with open holes on both sides of bulged area. This is 

considered acceptable ( if there is more significant distress is the result of grinding, provide 

borescope photo to PW for evaluation).

4.4. Move power switch to off position on control box, .Remove blend tool and bore scope from vane. Insert 

mock up eddy current probe to see if it passes through vane inner passage.

4.5. If additional excess material is present, or the mock up probe cannot not pass through, the spherical

blend tool (green color on shaft) can be used to remove more excess material.

4.6. Repeat the above steps as necessary to allow access for the eddy current probe.

4.7. When blending is completed, move power switch to off position on control box. Remove all equipment from 

vane.

5. Blend Procedure for T2V Excess Casting Flash @ air passage exit to air seal

5.1. Borescope and blend tool are placed into the same T2V transfer tube, but you must insert them and 

remove them in a certain order or damage may result to the borescope. Insert the borescope first, 

and remove the borescope last. If you need to alter from this order, use caution not to damage the 

bore scope with the blend tool.

5.2. Insert the 2 mm borescope into the aft side of the vane transfer tube opening and push scope thru the tube 

until the exit opening is visible. Inspect exit opening for evidence of a lip of flashing material at the “U” 

shaped portion of the opening to the inspector’s left. Continue inserting the bore scope thru and past 

the opening towards the inner air seal.

5.3. Insert the cone shaped blend tool into the forward side of the vane transfer tube opening and gently push 

blend tool thru the vane tube. Some resistance may be experienced as it goes thru the tightly curved 

portion near ID of vane. Gently push and twist as necessary while inserting until marked portion of blend 

tool’s Teflon tube is lined up with entrance of the transfer tube opening. The blending tool tip is now in 

approximately the correct blending location at the I.D. of the T2V transfer tube exit.

5.4. Gently pull bore scope back to view blend tool tip at the air passage exit (see Figures E and F). Twist and 

position bore scope to get a good view of blending area. Keep a safe distance between the borescope 

and blend tool. Reposition blend tip as necessary to grind away edge of excess flash material. See 

Fig. E.
NDIP 1137

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

28

FIGURE E : 

Blending tip in correct position while blending

5.5. Always blend at a slow speed. Always start with the cone shaped blend tip and gradually change to 

the spherical tip as needed to remove additional material. The flexible shaft of the blend tool may fail if 

the blend tip gets jammed. Use only the forward motor direction. Blend tool shaft failure may result 

from using the reverse motor direction.

NOTE:: Use caution not to jam blend tip or cable may break. If the blend tip liberates, every effort 

should be used to recover the liberated material. If the liberated material is not recoverable, see the 

Service Bulletin accomplishment section for continue in service direction.

5.6. Turn motor switch to on position. With blend tip at correct location, press foot pedal and gently move 

cone blend tool in and out slightly to remove excess flash material on the bottom of the “U” shaped

opening. Remove as much excess material as possible with the cone blend tool. Also remove excess 

material from the sides of the “U” shaped slot if present. Move the power to off position on the

control box. Remove blend tool from vane. Inspect area with borescope. If sufficient material is 

removed (Figure F), remove borescope and try mock up probe for passage through the transfer tube. 
NDIP 1137

P&W PROPRIETARY INFORMATION ECCN 9E991- EXPORT CONTROLLED

29

FIGURE F 

HPT T2V transfer tube air passage exit after blending

5.7. If the mock up probe does not pass thru, the spherical ball blend tool (green color on shaft) can be used 

to remove additional material further up the sides of the “U” shaped opening.

5.8. Repeat the above steps as necessary to allow pass through for mock up probe.

5.9. When blending is completed, move power switch to off position on control box. Remove all equipment from 

vane.