CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
Revised: 05/14
CF34BJ SERVICE BULLETIN - 72-0345 R00
/2024
SB 72-0345 R00 ENGINE - COMPRESSOR STATOR (72-32-00) - ONE-TIME VARIABLE Issued: 05/14
GEOMETRY SYSTEM FUNCTIONAL CHECK /2024
GE Designated: -CONFIDENTIAL-
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 part.
This technical data is considered subject to the Export Administration Regulations (EAR) pursuant to 15 CFR Parts 730-774.
Transfer of this data by any means to a Non-U.S. 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 (2024) General Electric Company, U.S.A.
1. PLANNING INFORMATION
A. Effectivity
* * * CF34-1A/-3A/-3A1/-3A2/-3B
This Service Bulletin is applicable to the below CF34-BJ engines, which have experienced a hung start in the last 24
months.
NOTE: Operators of all engines are encouraged to check their maintenance records to determine if their engines are
impacted by this Service Bulletin.
* CF34-1A/-3A/-3A2 engines, serial numbers 350103 through 350525.
* CF34-3A1 engines, serial numbers 807001 through 807661.
* CF34-3B engines, serial numbers 872001 through 873999, 950000 through 950999, and 801001 through 801714.
NOTE: For impacted engines, if the lower case P/N 6040T84P01, upper case P/N 6040T84P02, lower case P/N
6052T48P01, upper case P/N 6052T48P02, or compressor case assemblies P/N 6078T70G01 and P/N 6078T70G02
have been removed and repaired in accordance with SEI-582, 72-31-00, REPAIR 09 or SEI-782, 72-32-16,
REPAIR 07 or 72-32-17, REPAIR 07 since the last time hung start was experienced, then this Service Bulletin is
not applicable.
NOTE: For impacted engines, if Maintenance Practice 68, SEI-780, 72-00-00, MAINTENANCE PRACTICE 68 has been
performed within the past eight weeks, share results with GE for further recommendation if necessary to repeat
steps 3.A.(1) through 3.A.(3) of this Service Bulletin.
NOTE: A hung start, as defined in SEI-580, 72-00-00, FAULT ISOLATION and SEI-780, 72-00-00, FAULT
ISOLATION 07, is frequently called an N2 stagnation and it is seen when the engine lights off normally but
cannot accelerate to reach the idle speed limits specified in SEI-580, 72-00-00, TESTING, Figure 505 or SEI-780,
72-00-00, TESTING, Figure 512 in the time specified in SEI-580, 72-00-00, TESTING, Figure 504 or SEI-780, 72-
00-00, TESTING, Figure 509.
B. Description
This Service Bulletin provides instructions to do a one-time inspection of the affected engines aimed to identify
possible interface corrosion/obstruction between the compressor case, compressor case bushing, vane spindle, and
compressor stator variable vane.
C. Compliance
Category 2
GE recommends that you do this Service Bulletin as soon as possible without effect on their operation as follows:
GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or reproduced
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CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
(1) If an aircraft has two affected engines, do as follows:
(a) On one engine of the affected aircraft, obey the instructions in paragraph 3., ACCOMPLISHMENT
INSTRUCTIONS within 10 flight cycles from the issue date of this Service Bulletin.
(b) On the other engine of the affected aircraft, obey the instructions in paragraph 3., ACCOMPLISHMENT
INSTRUCTIONS within 30 flight cycles from the issue date of this Service Bulletin.
(2) If an aircraft has only one affected engine, do as follows:
(a) On the affected engine, obey the instructions in paragraph 3., ACCOMPLISHMENT INSTRUCTIONS
within 60 flight cycles from the issue date of this Service Bulletin.
Impact C
This recommendation is to address a condition that may result in a Non-Event operational disruption, Unscheduled
Engine Removals (UER), Out-Station-Removals or Aircraft on the Ground (AOG).
NOTE: This Service Bulletin can be done on wing or in shop.
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 identify engines exhibiting corrosion in and around the high pressure compressor (HPC) case variable stator
vane bores which could lead to operational disruptions.
(2) Condition:
The actuating linkage assembly has been found to bind or stick resulting in engine operation with off-schedule
variable stator vanes, leading to hung starts or potential unscheduled engine removals.
(3) Cause:
Corrosion has been found on the inside of the compressor case around the variable geometry stator vanes bores,
resulting in binding, sticking, and seizure of the compressor stator variable vanes during engine operation.
(4) Inspection:
The inspection of the actuating linkage assembly will aid operators in the early detection of corrosion build-up
on the inside of the compressor case and around the compressor vane spindle bushing bores to prevent
operational disruptions.
(5) Substantiation:
Substantiation is by analysis and fleet experience.
F. Approval
The data contained in this Service Bulletin has been reviewed by the FAA or authorized entity representing the FAA
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 actuating linkage assembly, you will need approximately 8 to 12 man-hours to do the
inspection portion of this Service Bulletin.
H. Weight and Balance
Weight and balance are not changed.
I. References (Use the latest version of these documents)
GEK 9250, Commercial Engine Standard Practices Manual (SPM)
SEI-580, CF34-BJ Maintenance Manual (MM)
SEI-581, CF34-BJ-1A_3A_3A2 Engine Illustrated Parts Catalog (IPC)
SEI-582, CF34-BJ Shop Manual (SM)
SEI-779, CF34-BJ Engine Illustrated Parts Catalog (IPC)
SEI-780, CF34-BJ Service Manual (SM)
SEI-782, CF34-BJ Heavy Maintenance Manual (HMM)
J. Publications Affected
GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or reproduced
Date Printed: 2024 without the express written consent of GE. Technical data is considered ITAR and/or EAR Page
/07/04 controlled; transfer of this data to a Non-US Person, without USG authorization, is strictly 2 of 7
prohibited.
CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
None.
K. Interchangeability
Not applicable.
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:
None.
(3) Consumables:
None.
B. Industry Support Information
None.
C. Configuration Chart
None.
D. Parts Disposition
None.
E. Tooling - Price and Availability
Tool Number Description
-- Cart, Compressed Gas (Nitrogen or Air)
3. ACCOMPLISHMENT INSTRUCTIONS
A. General
(1) Before you start these procedures, read the assembly and disassembly techniques section. Refer to GEK 9250,
70-10-00, ASSEMBLY AND DISASSEMBLY TECHNIQUES.
(2) Do a check of the variable geometry system (Figure 1) freeness in accordance with the applicable SEI-580, 72-
00-00, SPECIAL MAINTENANCE PRACTICES, paragraph 14., Variable Geometry System - Maintenance
Practice 68 or SEI-780, 72-00-00, MAINTENANCE PRACTICE 68.
(3) Do the functional checks and adjustments of the fuel system after maintenance. Use the applicable SEI-580, 72-
00-00, TESTING, Table 503 or SEI-780, 72-00-00, TESTING, Figure 510 to estimate the testing necessary as
it relates to hardware removed in accomplishment of this Service Bulletin.
(4) Do an engine test. Refer to the applicable SEI-580, 72-00-00, TESTING or SEI-780, 72-00-00 TESTING, and
as follows:
(a) Start the engine and set at idle speed for 5 minutes.
(b) Increase the engine speed to make sure that the interstage turbine temperature (ITT) is set to 1501 F (816
C) degrees or more. Operate the engine at this temperature for 23 minutes.
(c) Retard the power lever to idle speed and hold for 2 minutes.
(d) Shut down the engine and wait for 30 minutes.
(e) Start the engine.
NOTE: An engine rollover must not be done before the start procedure is tried, and the ITT must be at 248 F
(120 C) degrees or less before the engine ignition. This will help to keep the thermal state of the engine.
(5) Send the inspection report (Figure 2) to GE for tracking purposes to the e-mail addresses that follow:
E-mail (USA): aviation.fleetsupport@ge.com
E-mail (China and Asia): aviation.fleetsupport.cn@ge.com
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Date Printed: 2024 without the express written consent of GE. Technical data is considered ITAR and/or EAR Page
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CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
Variable Geometry System
Figure 1
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CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
Inspection Data Request
Figure 2
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/07/04 controlled; transfer of this data to a Non-US Person, without USG authorization, is strictly 5 of 7
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CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
Variable Geometry Actuator in the Fully-Extended Position
Figure 3
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Date Printed: 2024 without the express written consent of GE. Technical data is considered ITAR and/or EAR Page
/07/04 controlled; transfer of this data to a Non-US Person, without USG authorization, is strictly 6 of 7
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CF34BJ Service Bulletins (SBs)
SB 72-0345 R00 ENGINE - Compressor Stator (72-32-00) - One-Time Variable Geometry System Functional Check
Variable Geometry Actuator in the Fully-Closed Position
Figure 4
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GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or reproduced
Date Printed: 2024 without the express written consent of GE. Technical data is considered ITAR and/or EAR Page
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