# General Electric Service Bulletin 72-0331: No revision named

- Rights: © General Electric Company. Filed by the FAA in regulations.gov docket FAA-2018-0224, the docket of AD 2018-14-12. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [General Electric Service Bulletin 72-0331](https://openairdocs.org/service-documents/ge/sb-72-0331.md)
- Title as filed: GEnx-1B-SB-72-0331-R01 (1)
- Pages: 5
- PDF: https://openairdocs.org/files/sha256/46/45/4645a181a3eaadfc1fd7b6e66d77963f93ab5f1fabed97df0d80841d45254b66
- Page: https://openairdocs.org/service-documents/ge/sb-72-0331/file/4645a181a3ea

## Text

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### Page 1

GEnx-1B (LR) Service Bulletins (SBs)
SB 72-0331 R01 ENGINE - LPT Module (72-00-02) - Introduction of Reworked Extension Duct
Date Printed:
2017/12/08
GE PROPRIETARY INFORMATION - Not to be used, disclosed to
others or reproduced without the express written consent of
GE. Technical data is considered ITAR and/or EAR controlled;
transfer of this data to a Non-US Person, without USG
authorization, is strictly prohibited.
Page
1 of 5
GEnx-1B SERVICE BULLETIN - 72-0331 R01 Revised:08/21/2017
SB 72-0331 R01 ENGINE - LPT MODULE (72-00-02) -
INTRODUCTION OF REWORKED EXTENSION DUCT
Issued:
09/16/2016
GE PROPRIETARY INFORMATION
The information contained in this document is GE proprietary
information and is disclosed in confidence. It is the property of GE
and shall not be used, disclosed to others or reproduced without the
express written consent of GE, including, but without limitation, it is
not to be used in the creation, manufacture, development, or derivation
of any repairs, modifications, spare parts, designs, or configuration
changes or to obtain FAA or any other government or regulatory approval
to do so. If consent is given for reproduction in whole or in part,
this notice and the notice set forth on each page of this document
shall appear in any such reproduction in whole or in part.
This technical data is considered EAR controlled pursuant to 15 CFR
Parts 730-774 respectively. Transfer of this data by any means to a
Non-US Person, whether in the United States or abroad, without the
proper U.S. Government authorization (e.g., License, exemption, NLR,
etc.), is strictly prohibited.
Copyright (2017) General Electric Company, U.S.A.
TRANSMITTAL INFORMATION
REVISION 1 TO SERVICE BULLETIN 72-0331
Revision 1 is issued to update paragraph 1.C., .Compliance
The original was issued September 16, 2016. Revision bars in the left
margin identify changes.
1. PLANNING INFORMATION
A. Effectivity
* * * GEnx-1B64, -1B64/P1, -1B64/P2, -1B67, -1B67/P1, -1B67/P2, -1B70, -1B70/75/P1,
-1B70/75/P2, -1B70/P1, -1B70/P2, -1B70C/P1, -1B70C/P2, -1B74/75/P1, -1B74/75/P2
This Service Bulletin is applicable to these GEnx-1B engines:
*GEnx-1B engines, serial numbers 956-001 through 956-806.
This Service Bulletin has been introduced in production to these
GEnx-1B engines:
*GEnx-1B engines, serial numbers 956-807 and up.
These serial numbers are the best available data.
The air/oil (A/O) extension ducts (extension ducts) P/N 
 and P/N  are affected by this Service2332M85P01 2331M25G03
Bulletin.
B. Description
This Service Bulletin introduces a new extension duct P/N

### Page 2

GEnx-1B (LR) Service Bulletins (SBs)
SB 72-0331 R01 ENGINE - LPT Module (72-00-02) - Introduction of Reworked Extension Duct
Date Printed:
2017/12/08
GE PROPRIETARY INFORMATION - Not to be used, disclosed to
others or reproduced without the express written consent of
GE. Technical data is considered ITAR and/or EAR controlled;
transfer of this data to a Non-US Person, without USG
authorization, is strictly prohibited.
Page
2 of 5
 and a reworked extension duct P/N .2332M85P02 2331M25G04
Also, this Service Bulletin provides instructions to rework the
affected extension ducts.
C. Compliance
Category 3
GE recommends that you do this Service Bulletin at the next shop
visit of the engine/module.
Impact A
This recommendation is to address a condition that may affect
Flight Safety.
NOTE:This Service Bulletin can be done in shop.
NOTE:This applies also to quick-turn shop visits.
This Service Bulletin is offered to improve the reliability or
performance of your GE product, or to help prevent the occurrence
of the event or condition described in this Service Bulletin. If
the operator elects not to participate in the bulletin, that
decision will be taken into consideration by GE in evaluating
future product performance issues that may arise in the
operator's fleet.
D. Concurrent Requirements
None.
E. Reason
(1) Objective:
To introduce new parts, rework parts, and improve maintainability.
(2) Condition:
Routine teardowns have occurred at overhaul shop, finding tannic oil
collected in the fan mid shaft (FMS) with deteriorating paint, seals, coke,
and corrosion pittings of the FMS.
(3) Cause:
Oil leaking into the FMS inner cavity causes corrosion on the FMS inner
surface and degradation in O-rings and/or seal assembly.
(4) Improvement:
Introduction of a new extension duct with air holes in the front flange as
countermeasure against oil leaks into the FMS inner surface. A pressurized
air flow path through the holes avoids leaks during the operation.
For field engines: Rework the extension ducts with 18 air holes of 0.1968
inch (5.00 mm) diameter on the front flange as countermeasure against oil
leaking into the FMS.
(5) Substantiation:
Substantiation is by analysis and comparative analysis.
F. Approval
The data contained in this Service Bulletin has been reviewed by
the appropriate governmental authority and the repair(s) and
modification(s) herein comply with the applicable Aviation
Regulations and are APPROVED for installation in the model(s)
listed in this Service Bulletin.
G. Manpower
After you get access to the FMS, you will need approximately 4
man-hours for each engine or component.
H. Weight and Balance
Weight and balance are not changed.
I. References (Use the latest version of these documents)
GEK 112851, GEnx-1B Engine Manual (EM)

### Page 3

GEnx-1B (LR) Service Bulletins (SBs)
SB 72-0331 R01 ENGINE - LPT Module (72-00-02) - Introduction of Reworked Extension Duct
Date Printed:
2017/12/08
GE PROPRIETARY INFORMATION - Not to be used, disclosed to
others or reproduced without the express written consent of
GE. Technical data is considered ITAR and/or EAR controlled;
transfer of this data to a Non-US Person, without USG
authorization, is strictly prohibited.
Page
3 of 5
GEK 112862, GEnx-1B Cleaning, Inspection, and Repair Manual (CIR)
GEK 112864, GEnx-1B Engine Illustrated Parts Catalog (EIPC)
Repair Document (RD) 810-336 (L1 or higher), Low Pressure Turbine
Extension Duct - Alteration - Additional Air Holes to Forward
Flange
NOTE:The reference documents listed below are for the engine manufacturer's
internal use only:
CID: 943081
BPP: 16-79-00-55093
J. Publications Affected
GEK 112851, GEnx-1B Engine Manual (EM)
GEK 112862, GEnx-1B Cleaning, Inspection, and Repair Manual (CIR)
GEK 112864, GEnx-1B Engine Illustrated Parts Catalog (EIPC)
K. Interchangeability
One-way interchangeable.
L. Software Accomplishment Summary
Not applicable.
2. MATERIAL INFORMATION
A. Material - Price and Availability
(1) Parts necessary to do this Service Bulletin:
None.
(2) Other Spare Parts:
Part Number
Qty/
Eng Part Name
Unit ($)
Price 
Pkg
Qty
Lead Time
Days
2332M85P02 (1) Duct, A/O
Extension
16,270.00 (1) Quote
NOTE:Prices are provided for planning purposes and are subject to change.
(3) Consumables:
None.
B. Industry Support Information
None.
C. Configuration Chart
New 
Part Number
Qty/
Eng Part Name
Old Part Number/
IPC Location
Qty/
Eng
Op
Code
Chg/
Sprt
Code
(PRODUCTION ONLY)
2376M20G06/
G07/G08/G09
(X) Assembly,
Propulsor Module
2376M20G06/
G07/G08/G09
(X) RM -/-
2447M20G01/
G02/G03/G04
(X) Assembly,
Propulsor Module
2447M20G01/
G02/G03/G04
(X) RM -/-
.  2332M85P02
 45-270B,72-00-02
(1) Duct, A/O
Extension
(SIN 810A8)
.  2332M85P01
 45-270A,72-00-02
(1) RE/
RW/RI
1/A
(FIELD ONLY)
2376M20G05/
G06/G07/G08/
G09
(X) Assembly,
Propulsor Module
2376M20G05/
G06/G07/G08/
G09
(X) RM -/-
2447M20G01/
G02/G03/G04
(X) Assembly,
Propulsor Module
2447M20G01/
G02/G03/G04
(X) RM -/-
.  2332M85P02
 45-270B,72-00-02
(1) Duct, A/O
Extension
(SIN 810A8)
.  2332M85P01
 45-270A,72-00-02
(1) RE/
RW/RI
1/A
2376M20G05 (X) Assembly, 2376M20G05 (X) RM -/-

### Page 4

GEnx-1B (LR) Service Bulletins (SBs)
SB 72-0331 R01 ENGINE - LPT Module (72-00-02) - Introduction of Reworked Extension Duct
Date Printed:
2017/12/08
GE PROPRIETARY INFORMATION - Not to be used, disclosed to
others or reproduced without the express written consent of
GE. Technical data is considered ITAR and/or EAR controlled;
transfer of this data to a Non-US Person, without USG
authorization, is strictly prohibited.
Page
4 of 5
Propulsor Module
.  2331M25G04
 45-270C,72-00-02
(1) Duct, A/O
Extension
(SIN 810A8)
.  2331M25G03
 45-270,72-00-02
(1) RW/
RI
1/-
Operation Codes
RE=Replace
RI=Reidentify
RM=Remains
RW=Rework
Change Codes
1=One-way interchangeable.
Support Codes
A=Old parts will no longer be supplied.
D. Parts Disposition
Rework.
E. Tooling - Price and Availability
None.
3. ACCOMPLISHMENT INSTRUCTIONS
A. General
(1) Remove the extension duct (1, Refer to the GEnx-1B EM,Figure 1). 
72-00-04, DISASSEMBLY 001.
NOTICE
APPROVAL OF REWORK SOURCES
The repair referred to below contains complex processes that could affect
engine reliability and/or performance. Therefore it is necessary to
substantiate the ability and adequacy of a repair source to successfully
accomplish the repair. A Technical License Agreement is also required.
Information concerning a Technical License Agreement is available from:
ATTN.: Manager, Technical Licensing
GE Aviation
One Neumann Way, M/D RM100
Cincinnati, Ohio 45215-6301
U.S.A.
After the repair source has obtained a Technical License Agreement, the Repair
Document and the Repair Source Substantiation requirements may be obtained
from:
ATTN.: Repair Substantiation
GE Aviation
One Neumann Way, M/D S171
Cincinnati, Ohio 45215-6301
U.S.A.
OR
Phone: (513) 552-9563
Fax: (513) 552-9587
(2) Rework and reidentify the old extension duct (1, Refer to RDFigure 1). 
810-336.
(3) Install the new or reworked extension duct (1, Refer to theFigure 1). 
GEnx-1B EM, 72-00-04, ASSEMBLY 001, CONFIGURATION 01.

### Page 5 (OCR)

GEnx-1B (LR) Service Bulletins (SBS)
SB 72-0331 R01 ENGINE - LPT Module (72-00-02) - Introduction of Reworked Extension Duct
OLD CONFIGURATION
1 REF
LEGEND:
1. EXTENSION DUCT
REPLACE OLD PART
WITH NEW
P/N 2332M85P02 OR
REWORKED  NEW CONFIGURATION
P/N 2332M85P02 OR
P/N 2331M25G04  5033544-00
Extension Duct Replacement
Figure 1
GE PROPRIETARY INFORMATION - Subject to the restrictions on the media.
GE PROPRIETARY INFORMATION - Not to be used, disclosed to
Date Printed:  others or reproduced without the express written consent of  Page
2017/12/08  GE. Technical data is considered ITAR and/or EAR controlled;  5 of 5
transfer of this data to a Non-US  Person, without USG
authorization, is strictly prohibited.

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