# General Electric Alert Service Bulletin 72-A0137: CF34-8C SB 72-A0137 R05

- Rights: © General Electric Company. Filed by the FAA in regulations.gov docket FAA-2017-0164, the docket of AD 2017-17-18. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [General Electric Alert Service Bulletin 72-A0137](https://openairdocs.org/service-documents/ge/72-a0137.md)
- Title as filed: CF34-8C SB 72-A0137 R05
- Pages: 9
- PDF: https://openairdocs.org/files/sha256/cf/b3/cfb32f7a0536262c94021689ae40f093dc933526e5cfb25853e75bef38f3015f
- Page: https://openairdocs.org/service-documents/ge/72-a0137/file/cfb32f7a0536

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### Page 1

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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 9
CF34-8C ALERT SERVICE BULLETIN - 72- A0137 R05 Revised:06/15/2016
SB 72-A0137 R05 ENGINE - FAN ROTOR ASSEMBLY (72-00-21) -
INSPECTION OF FAN BLADES
Issued:
01/16/2007
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 (2016) General Electric Company, U.S.A.
TRANSMITTAL INFORMATION
REVISION 5 TO SERVICE BULLETIN 72-0137
Revision 5 is issued to update paragraphs 1., , 2.,PLANNING INFORMATION
, 3., , and to addMATERIAL INFORMATION ACCOMPLISHMENT INSTRUCTIONS
paragraphs 4.,  and 5., .APPENDIX A APPENDIX B
Revision 4 was issued October 29, 2013. Revision 3 was issued April 09,
2012. Revision 2 was issued August 18, 2011. Revision 1 was issued
February 19, 2010. The original was issued January 16, 2007. Revision
bars in the left margin identify changes.
1. PLANNING INFORMATION
A. Effectivity
* * * CF34-8C1
* * * CF34-8C5, -8C5B1, -8C5A1, -8C5A2, -8C5A3
* * * CF34-8C5/M, -8C5B1/M, -8C5A1/M, -8C5A2/M
* * * CF34-8C5/B, -8C5B1/B, -8C5A1/B, -8C5A2/B, -8C5A3/B
This Service Bulletin is applicable to all CF34-8C engines.
B. Concurrent Requirements
None.
C. Description
This Service Bulletin recommends an inspection initiation point

### Page 2

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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 9
of the fan blade pinholes via eddy current inspection (ECI), a
program for inspecting fan blade pinholes at recommended
intervals, a termination point of the inspection, and a
requirement to rework the fan blades.
D. Compliance
Category 2
(1) GE recommends that you begin with this inspection plan when the fan blades
accumulate the operating cycles since new (CSN) as follows:
Engine
Model
Group
Engine Thrust
Rating
Initial Inspection 
(Part Cycles)
Reduced Inspection (Part
Cycles)
Initial
Inspection
Threshold
Initial 
Inspection
Interval
Reduced 
Inspection 
Threshold
Reduced 
Inspection
Interval
Group 1
CF34-8C1,
CF34-8C5B1,
CF34-8C5B1/B
25,000 3,000 N/A N/A
Group 2
CF34-8C5, 
CF34-8C5/B,
CF34-8C5A1,
CF34-8C5A1/B,
CF34-8C5A2,
CF34-8C5A2/B
19,500 3,000 25,000 1,500
Group 3
CF34-8C5/M,
CF34-8C5A1/M,
CF34-8C5A2/M,
CF34-8C5A3
CF34-8C5A3/B
CF34-8C5B1/M
19,000 3,000 25,000 1,500
(2) GE recommends subsequent re-inspection of the affected fan blades in
compliance with this Service Bulletin as follows:
(a) At 41,000 part cycles, the fan blades are no longer serviceable and the
inspection plan terminates.
(b) At 41,000 part cycles, repair the fan blades per CF34-8C S/B  or72-0225
remove the fan blades and replace with serviceable fan blades.
Example:
For fan blades installed on CF34-8C5 that reached 19,500 part CSN, you
would do an ECI. Then, repeat the ECI at 22,500, 25,000, 26,500, 28,000,
29,500, 31,000, 32,500, 34,000, 35,500, 37,000, 38,500, and 40,000 part
cycles.
NOTE:Notice that once the fan blades reach 25,000 part CSN, the ECI interval
is reduced from 3,000 to 1,500 part cycles.
At 41,000 part CSN, the fan blades would have to be reworked per CF34-8C
S/B  or replaced with new serviceable fan blades of the same part72-0225
number.
(3) GE recommends that you do this Service Bulletin on the fan blades listed in
paragraph 1.A.,  at or as close as conveniently possible toEffectivity
the recommended inspection limits without exceeding the recommended
inspection limits.
NOTE:If the fan blades have cycles accumulated on one or more CF34 models and/or
have an unknown accumulated number of part cycles, refer to paragraph 4., 
.APPENDIX A
NOTE:This Service Bulletin can be accomplished 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

### Page 3

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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 9
decision will be taken into consideration by GE in evaluating
future product performance issues that may arise in the
operator's fleet.
E. Reason
(1) Objective:
(a) To recommend an initial inspection requirement for fan blade pinholes.
(b) To introduce an ECI and a program for inspecting fan blade pinholes at
recommended intervals.
(c) To recommend re-inspection at specified intervals until rework
procedures are completed for the affected fan blades.
(d) To introduce a termination point of the inspection plan and recommend
rework of the fan blades per CF34-8C S/B .72-0225
(e) To advise operators to maintain time since new (TSN) and CSN data of
their fan blades.
(f) To advise operators that GE has developed a rework procedure for the
fan blades. Refer to CF34-8C S/B .72-0225
(2) Condition:
Operation of fan blades beyond recommended limits could result in cracks
through one-half of a fan blade tang. These cracks could cause excessive
fan vibrations and heavy fan blade rubs which could lead to separation of
the fan blade.
(3) Cause:
During operation beyond recommended limits, the stresses in the fan blade
pinholes could result in crack initiation at pinhole surfaces, and
continuation through one-half of a fan blade tang.
(4) Improvement:
A reoccurring ECI plan has been initiated to inspect all the fan blades up
to 41,000 part cycles to reduce the probability of the cracks propagating
to failure. At 41,000 part cycles the fan blades must be reworked or
removed from service. Refer to CF34-8C S/B .72-0225
(5) Substantiation:
Analysis and component testing have indicated that the minimum fan blade
low cycle fatigue (LCF) capability is less than the published aircraft
life. The ECI initiation point is based on crack initiation. It is set
below the minimum fan blade LCF capability. The ECI interval is based on
crack propagation. The reinspection interval is below the predicted minimum
crack propagation rate.
F. Approval
This Service Bulletin has been reviewed by the FAA and the
repair(s) and modification(s) herein comply with the applicable
Federal Aviation Regulations and are FAA APPROVED for
installation in the model(s) listed in this Service Bulletin.
G. Manpower
For planning purposes, the following times apply:
*The approximate time required to remove and install a fan blade set is 
4 man-hours.
*The approximate time required to accomplish an ECI of an uninstalled fan
blade set in accordance with the recommendations in this Service Bulletin is
4 man-hours.
NOTE:The approximate time required to accomplish an ECI of a single uninstalled
fan blade is 1 man-hour.
*The approximate time required to strip and re-coat the heat cured lubricant
on an uninstalled fan blade set is 24 man-hours.
H. Weight and Balance
Weight and balance are not changed.
I. References (Use the latest version of these documents)
GEK 105091, CF34-8C Engine Manual (EM)

### Page 4

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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 9
GEK 9250, Commercial Engine Standard Practices Manual (SPM)
CF34-8C-AL S/B , ENGINE - Fan Rotor Assembly (72-21-00) -72-0225
Introduction of Fan Blade Bushing Repair
CF34-8E-AL S/B , ENGINE - Fan Rotor Assembly (72-00-21) -72-0060
Inspection of Fan Blades
J. Publications Affected
GEK 105091, CF34-8C Engine Manual (EM)
K. Interchangeability
If a fan blade is replaced in accordance with this Service
Bulletin, the replacement fan blade will be physically and
functionally interchangeable with the fan blade it replaces.
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:
(a) If fan blades need to be replaced due to inspection results, refer to
the table below.
Part Number Qty/ Eng Part Name
Unit ($) Price
Pkg Qty
Lead
Time
Days
4114T15P02 (AR) Fan Blade 12,000.00 (2) 30
NOTE:Prices are provided for planning purposes and are subject to change.
(3) Consumables:
None.
B. Industry Support Information
(1) Materials that can be required to accomplish this Service Bulletin are
listed in paragraph 2.A.(2), .Other Spare Parts
(2) Material and labor cost estimates may be obtained from any GE Aircraft
Engines authorized service or overhaul facility upon request. Material and
labor costs are the responsibility of the operator.
C. Configuration Chart
None.
D. Parts Disposition
If you do not have GE ECI certification, return the fan blades to
one of these GE certified ECI sources:
GE Aircraft Engines
Maintenance Center
Strother Field
Arkansas City, KS 67005
+1 620-442-3600
U.S.A.
OR
Standard Aero
33 Allen Dyne Road
Winnipeg, Manitoba
Canada R3H 1A1
+1 204-789-1800
OR
Lufthansa Technik AERO Alzey GmbH
Rudolf -Diesel-Strasse 10

### Page 5

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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
5 of 9
55232 Alzey, Germany
+49 6731-497-0
OR
MTU Maintenance
Berlin-Brandenburg GmbH
Dr.-Ernst-Zimmermann-Strae 2
14974 Ludwigsfelde, Germany
+49 3378-824-0
OR
IHI Mizuho Plant
229 Tonogaya Mizuho-Machi
Nishi Tama-Gun Tokyo, Japan
190-1212
+81 42-568-7371/7103
E. Tooling - Price and Availability
NOTE:For approved eddy current instruments, probe rotors, and other tooling, refer
to GEK 105091, 72-09-05, INSPECTION 001.
Tool Number Description
GE-FQAP-3XX*+ 300 Series Inspection Kit
GE-FQAP-446 Fan Blade Pin Hole Inspection Kit
J058077G01+ Guide Fixture
-- Cables and Adapters
-- Eddy Current Instrument
-- High Speed Probe Rotor
*Includes J050884G01 guide fixture (which is for the CF34-3 fan
blades; this may be omitted at request), two probes, and a
calibration standard. The kit depends of the eddy current
instrument being used.
+Locally manufactured probe alignment tooling can be used as
alternative to the recommended tooling.
Inspection kits with the reference number of GE-FQAP-XXX and
guide fixture  can be obtained from:J058077G01
GE Inspection Technologies
Attn.: NDE Kit Coordinator
50 Industrial Park Road
Lewistown, PA 17044
U.S.A.
Email: ndttooling@ge.com
Fax: 513-552-1386
3. ACCOMPLISHMENT INSTRUCTIONS
A. General
NOTE:Maintenance facilities where the inspections will be performed must be
approved by GE. Maintenance facilities that are approved to perform the ECI
for the CF34-3 fan blade pinholes are considered approved sources to perform
the ECI for the CF34-8 fan blade pinholes, although the CF34-8 guide fixture
J058077G01 might need to be procured.
NOTE:To become a GE certified ECI source, contact GE Fleet Support at:
Phone: (513) 552-3272
OR
E-mail: aviation.fleetsupport@ge.com
NOTE:To become a GE certified ECI source you must have a certified level II eddy
current inspector and must purchase the ECI equipment.
NOTE:If you do not have GE ECI certification, refer to paragraph 2.D., Parts
.Disposition

### Page 6

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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
6 of 9
B. Removal
Remove the fan blades. Refer to GEK 105091, 72-00-21, Removal.
NOTE:Mark the fan blades relative to the 0-mark. This is important to make sure
that the fan blades are reinstalled in the same order to minimize balance
issues after completing this procedure.
C. Inspection of Fan Blades
(1) Do an inspection of the fan blades pin holes. Refer to GEK 105091,
72-09-05, INSPECTION 001, step 3.C.
D. Deleted
E. Installation
Reinstall the fan blades. Refer to GEK 105091, 72-00-21,
Installation.
NOTE:Install the fan blades with the No.1 fan blade at the 0-mark to make sure
that they are installed in the same clocking locations as when they were
removed.
F. Testing
Do an on-wing test. Refer to GEK 105091, 72-00-00, Testing 001,
Figure 1312 for required testing.
4. APPENDIX A - FAN BLADES USED ON MULTIPLE MODELS OR WITH UNKNOWN
ACCUMULATED CYCLES
NOTE:If you have a situation which is not defined below, please contact your
Customer Service Manager.
A. If the quantity of part cycles accumulated on one or more CF34-8
models/configurations is accurately known and documented, the initial
inspection limit for a part used in more than one CF34-8 model/configuration
can be calculated by pro-rating the cycles consumed. Calculate the fraction of
cycles used for a part installed in a given CF34-8 model/configuration, then
calculate the remaining part CSN for the part installed in a different CF34-8
model/configuration, as follows:
(1) Calculate the fraction of life used for a part installed in initial CF34-8
model/configuration as follows:
Fraction of
life used = Cycles accumulated on CF34-8 model 1LCF limit for CF34-8 model 1
(2) Use this fraction and calculate the remaining CSN on the part if installed
in another different CF34-8 model (model 2) as follows:
Cycles
remaining
for CF34-8
model 2
= [ 1.0
Fraction of life
used
(from above)
] X LCF limit forCF34-8 model 2
(3) Determine the Inspection Interval (for fan blades which the part cycles are
known)
Once the inspection plan has begun, for a part used in more than one CF34-8
models/configurations the re-inspection interval is determined as follows:
(a) If the fan blade has not changed models/configurations since the last
inspection, follow the re-inspection interval listed below:
1 For parts that operate on group 1 engines listed in 1.D., 
, re-inspect every 3,000 part cycles.Compliance
2 For parts that operate on group 2 and group 3 engines listed in
1.D., , re-inspect every 1,500 part cycles.Compliance
(b) If the part is changing models/configurations immediately, do an
inspection of the part, then follow the re-inspection interval as
follows:
1 For parts that will operate on group 1 engines, re-inspect every
3,000 part cycles.
2 For parts that will operate on group 2 and group 3 engines,
re-inspect every 1,500 part cycles.
B. For fan blades where the part CSN is unknown, it is recommended that the

### Page 7

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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
7 of 9
operator assume that the part CSN is equal to the CSN on the highest-time
engine in the operator's fleet. Base the recommendation for inspection on that
CSN. This applies only if the operator has not purchased any fan blades with
unknown part CSN that may have been owned by a previous operator.
(1) Determine the Inspection Interval (for fan blades which the part cycles are
unknown)
If the part cycles are unknown and the assumed quantity of part cycles is
more than the inspection start point, immediately do an inspection of the
part, then follow the re-inspection interval as follows:
(a) For parts that will operate on group 1 engines, re-inspect every 3,000
part cycles.
(b) For parts that will operate on group 2 and group 3 engines, re-inspect
every 1,500 part cycles.
C. For fan blades that have been purchased with the part CSN unknown and could
have been owned by a previous operator, it is recommended that the operator
assume that the part CSN is equal to the CSN on the highest-time engine in the
fleets. Base the recommendation for inspection on that CSN. Operators should
work with their assigned Customer Support Manager to get this highest-time
engine information.
(1) Determine the Inspection Interval (for fan blades which the part cycles are
unknown)
If the part cycles are unknown and the assumed quantity of part cycles is
more than the inspection start point, immediately do an inspection of the
part, then follow the re-inspection interval as follows:
(a) For parts that will operate on group 1 engines, re-inspect every 3,000
part cycles.
(b) For parts that will operate on group 2 and group 3 engines, re-inspect
every 1,500 part cycles.
D. For fan blades that have been purchased with part CSN unknown, the initial
purchase date of the fan blade is known, and the fan blade has not been
installed on any other operator, the operator can use the maximum usage rate
of their fleet to estimate the part CSN.
(1) Determine the Inspection Interval (for fan blades which the part cycles are
unknown)
If the part cycles are unknown and the assumed quantity of part cycles is
more than the inspection start point, immediately do an inspection of the
part, then follow the re-inspection interval as follows:
(a) For parts that will operate on group 1 engines, re-inspect every 3,000
part cycles.
(b) For parts that will operate on group 2 and group 3 engines, re-inspect
every 1,500 part cycles.
NOTE:The fan blade is a common part for CF34-8C and CF34-8E engines. If the fan
blade is being moved between CF34-8C and CF34-8E fleets, the mixed fleet
methodology described in this Service Bulletin is still applicable. Please
refer to the equivalent CF34-8E-AL S/B 72-  for the inspection threshold,0060
re-inspection interval, and reduced inspection intervals (if applicable) by
thrust.
5. APPENDIX B - Examples of Prorated Calculations for Mixed Model Fan
Blades
Examples Where Part CSN and Model History is Accurately Known and Documented
Example 1 - Low Thrust to High Thrust Model Switch Before Inspection Starting Point
A set of fan blades operates on a CF34-8C5B1 for 10,000 cycles and then switches to a
CF34-8C5. The prorated initiation point is calculated as follows:
Fraction of life used = Cycles accumulated on CF34-8C5B1/LCF limit for the CF34-8C5B1
= 10,000/25,000 = 0.4
Cycles remaining for CF34-8C5 = 1 - Fraction of life used X LCF limit for CF34-8C5 =
(1-0.4)X19,500= 11,700 cycles
Therefore, the inspection would begin in 11,700 cycles (or at 21,700 part CSN). The

### Page 8

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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
8 of 9
inspection would occur every 1,500 part cycles. The fan blades should be reworked at
41,000 part CSN or sooner.
Example 2 - High Thrust to Low Thrust Model Switch Before Inspection Starting Point
A set of fan blades operates on a CF34-8C5 for 10,000 cycles and then switches to a
CF34-8C5B1. The prorated initiation point is calculated as follows:
Fraction of life used = Cycles accumulated on CF34-8C5/LCF limit for the CF34-8C5 =
10,000/19,500 = 0.52
Cycles remaining for CF34-8C5B1 = 1 - Fraction of life used X LCF limit for
CF34-8C5B1 = (1- 0.52)X25,000 = 12,000 cycles
Therefore, the inspection would begin in 12,179 cycles (or at 22,179 part CSN). The
inspection would occur every 3,000 part cycles. The fan blades should be reworked at
41,000 part CSN or sooner.
Example 3 - Low Thrust to High Thrust Model Switch After Inspection Starting Point
A set of fan blades operates on a CF34-8C5B1 for 30,000 cycles and then switches to a
CF34-8C5. Since the inspection has already occurred, there is no need to calculate
the inspection starting point.
The fan blades should be inspected before returning the engine to service and
continue to occur every 1,500 cycles. The fan blades should be reworked at 41,000
part CSN or sooner.
Example 4 - High Thrust to Low Thrust Model Switch After Inspection Starting Point
A set of fan blades operates on a CF34-8C5 for 30,000 cycles and then switches to a
CF34-8C5B1. Since the inspection has already occurred, there is no need to calculate
the inspection starting point.
The fan blades should be inspected before returning the engine to service and
continue to occur every 3,000 part cycles. The fan blades should be reworked at
41,000 part CSN or sooner.
Example 5 - Low Thrust to High Thrust Model Switch After Inspection Starting Point
A set of fan blades operates on a CF34-8C5 for 30,000 cycles and then switches to a
CF34-8C5B1. Since the inspection has already occurred, there is no need to calculate
the inspection starting point.
The fan blades should be inspected before returning the engine to service and
continue to occur every 3,000 part cycles. The fan blades should be reworked at
41,000 part CSN or sooner.
Part Cycles Accumulated are Known, but not by Model Examples
Example 6 - Mixed Fleet
You have a fleet of CF34-8C5B1 and CF34-8C5 engines. Fan blades have been switched
between the two fleets and the quantity of cycles accumulated on the individual fan
blades by model is not known. Some of the fleet has passed the inspection point
(19,500 part cycles). Treat the two fleets as CF34-8C5. Start the inspection at
19,500 part cycles and do an inspection of the part every 3,000 part cycles until
25,000 part cycles. Then do an inspection of the part every 1,500 part cycles until
41,000 part cycles where the fan blades are reworked.
Example 7 - Mixed Fleet before inspection point
You have a fleet of CF34-8C5B1 and CF34-8C5 engines. Fan blades have been switched
between the two fleets and the quantity of cycles accumulated on the individual fan
blades by model is not known. None of the fleet has passed the inspection point and
processes are in place to prevent mixing go forward. For the CF34-8C5 start the
inspection at 19,500 part cycles and do an inspection of the part every 3,000 part
cycles until 25,000 part cycles. Then do an inspection of the part every 1,500 part
cycles until 41,000 part cycles where the fan blades are reworked. For the CF34-8C5B1

### Page 9

CF34-8C Service Bulletins (SBs)
SB 72-A0137 R05 ENGINE - Fan Rotor Assembly (72-00-21) - Inspection of Fan Blades
Date Printed:
2016/12/19
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
9 of 9
start the inspection at 19,500 part cycles and do an inspection of the part every
3,000 part cycles until 41,000 part cycles where the fan blades are reworked.
GE PROPRIETARY INFORMATION - Subject to the restrictions on the media.

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