ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
CFM PROPRIETARY INFORMATION
The information contained in this document is CFM proprietary information and is disclosed in confidence. It is the property of CFM and shall not be used, disclosed to others or reproduced without the
express written consent of CFM, including, but without limitation, it is not to be used in the creation,
manufacture, development, or derivation of any repairs, modifications, spare parts, design, 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. The information contained in
this document may also be controlled by U.S. export control laws. Unauthorized export or re-export
is prohibited.
All technical documentation and information contained herein, with respect to assembly and disassembly, cleaning, inspection methods and limits, repair methods and limits, operational limits, life
limits and the like, have been developed and approved for use with engines and parts that have been
manufactured and/or approved by CFM and that have been maintained in accordance with CFM
technical documentation and recommendations. CFM has no contractual or legal obligation for, nor
knowledge of, non-CFM-approved parts and repairs. Accordingly, this document is not intended to
apply to non-CFM-approved parts and repairs.
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 1 of 15
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
TRANSMITTAL INFORMATION
REVISION 3 TO SERVICE BULLETIN 72-0921
Revision 3 is issued to update paragraph 3., ACCOMPLISHMENT INSTRUCTIONS.
Revision 2 was issued August 03, 2017. Revision 1 was issued October 28, 2015. The original was
issued September 04, 2015. Revision bars in the left margin identify changes.
1.
PLANNING INFORMATION
A.
Effectivity
CFM56-5B1/2P, -5B1/3, -5B1/P, -5B2/2P, -5B2/3, -5B2/P, -5B3/2P, -5B3/2P1,
-5B3/3, -5B3/3B1, -5B3/P, -5B3/P1, -5B4/2P, -5B4/2P1, -5B4/3, -5B4/3B1, -5B4/P,
-5B4/P1, -5B5/3, -5B5/P, -5B6/2P, -5B6/3, -5B6/P, -5B7/3, -5B7/P, -5B8/3, -5B8/P,
-5B9/2P, -5B9/3, -5B9/P
(1)
This Service Bulletin is applicable to engines post-CFM56-5B S/B 72-0612 or
CFM56-5B S/B 72-0672 and pre-CFM56-5B S/B 72-0906.
(2)
This Service Bulletin is applicable to production engines with engine serial
numbers (ESNs) 57T637 and up. Refer to CFM56-5B S/B 72-0612 and
CFM56-5B S/B 72-0672.
NOTE:
(3)
This Service Bulletin is not applicable to production engines beginning with
ESNs 56V435 and up. Refer to the CFM56-5B S/B 72-0906.
NOTE:
(4)
The letter "T" refers to either 6 or 7.
The letter "V" refers to either 8 or 9.
Refer to CFM56-5B S/B 72-0781 for additional information on CFM ESN
sequencing.
These serial numbers are the best available data.
B.
Description
This Service Bulletin provides instructions, limits, and corrective actions for a
flexible borescope inspection (BSI) on the affected engines in order to detect and
monitor rotation of stage 2 and stage 3 high pressure compressor (HPC) stator
inner honeycomb seals.
This Service Bulletin also provides instructions, limits, and corrective actions for a
flexible BSI on the affected engines which are also equipped with post-CFM56-5B
S/B 72-0678 (slab head) anti-rotation pins to detect and monitor the rotation of
the stage 3 slab head anti-rotation pins.
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 2
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
C.
Compliance
Category 2
CFM recommends that you do this Service Bulletin as soon as possible without
effect on revenue service for engines with 10000 plus or minus 1000 cycles since
new (CSN) or cycles since installation of overhauled HPC variable stator vane
(VSV) system post-CFM56-5B S/B 72-0612 or post-CFM56-5B S/B 72-0672 was
installed, with a recurring inspection at 5000 plus or minus 800 cycles.
For CFM56-5B engines over 10000 CSN or cycles since installation of overhauled
HPC VSV system post-CFM56-5B S/B 72-0612 or post-CFM56-5B S/B 72-0672
was installed, at the time of this Service Bulletin issuance, do this inspection within
5000 plus or minus 800 cycles since the last HPC blade BSI.
Reduced repeat inspections may be recommended. The reinspection
intervals depend on the amount of distress found. Refer to paragraph 3.,
ACCOMPLISHMENT INSTRUCTIONS.
Impact B
This recommendation is to address a condition that may result in an Increased Rate
of In-Flight Shutdowns (IFSD), Take-Off Aborts (TOA), Air Turn Backs (ATB) or
Diversions (DIV).
NOTE 1:
This Service Bulletin can be accomplished on wing or in shop.
NOTE 2:
Inspection for engines with post-CFM56-5B S/B 72-0906 is not necessary.
This Service Bulletin is offered to improve the reliability or performance of your CFM
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 CFM in evaluating future product performance
issues that may arise in the operator’s fleet.
D.
Concurrent Requirements
Check CFM56-5B S/B 72-0727 for potential concurrent compliance.
E.
Reason
(1)
Objective:
To reduce the possibility of a liberation of a metallic bushing, a stage 2 and
stage 3 radial retention pin (straight pin), or a stage 3 slab headed anti-rotation
pin. Liberation of this hardware could result in impact damage to HPC airfoils
or life limited part (LLP) hardware, and/or engine stall.
(2)
Condition:
The HPC stator inner honeycomb seals can rotate on the HPC VSV inner
shroud, which can lead to liberation of a metallic bushing, a stage 2 and stage
3 radial retention pin (straight pin), or a stage 3 slab headed anti-rotation pin.
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 3
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
(3)
Cause:
Wear on the VSV shroud anti-rotation pins (Figure 2) at the 3:00 and 9:00
o'clock positions allows the stage 2 and stage 3 honeycomb seal to shift and
rotate during operation.
For metallic bushing liberation, the seal can contact and wear through the
round headed (pre-CFM56-5B S/B 72-0678) or slab headed (post-CFM56-5B
S/B 72-0678) anti-rotation pin. If the seal continues to rotate, it is possible for
the bushing to liberate through the gap between the seal segments.
For straight pin liberations, the seal can contact and wear through the round
headed (pre-CFM56-5B S/B 72-0678) or slab headed (post-CFM56-5B S/B
72-0678) anti-rotation pin. If the seal continues to rotate, it is possible for the
straight pin to liberate aft through the gap between the seal segments.
For stage 3 slab headed (post-CFM56-5B S/B 72-0678) anti-rotation pin
liberations, the seal can rotate and contact the slab head pin. The seal can
wear into the pin head and cause the pin head to rotate with the potential to
liberate forward out of the shroud and into the HPC flowpath.
(4)
Inspection:
This Service Bulletin provides a flexible BSI of the forward side of the stage 2
and stage 3 HPC VSV inner shrouds to determine engine serviceability.
(5)
Substantiation:
Substantiation is by fleet experience.
This inspection of seal rotation and the anti-rotation pin has been
demonstrated on engines in service.
F.
Approval
The technical content of this Service Bulletin is approved by the FAA and under the
Authority of DOA No. EASA.21J.086.
G.
Manpower
Approximately 1 man-hour for each engine will be required to accomplish the
flexible BSI of the forward side of the stage 2 and stage 3 HPC VSV inner shrouds.
H.
Weight and Balance
Weight and balance are not changed.
I.
References (Use the latest version of these documents)
Airbus A318/A319/A320/A321 Aircraft Maintenance Manual (AMM)
CFM56-5B S/B 72-0612, ENGINE - HPC Stator Forward Assembly (72-32-00) Stage 2 and Stage 3 Improved Inner Bushings, Vanes, Seals and Shrouds
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 4
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
CFM56-5B S/B 72-0672, ENGINE - Compressor Front Stator Assembly (72-32-00) Introduction of New Metallic-Composite VSV Bushing
CFM56-5B S/B 72-0678, ENGINE - Compressor Front Stator (72-32-00) Introduction of a New Anti-Rotation Straight Headed Pin
CFM56-5B S/B 72-0727, ENGINE - Compressor Rotor Assembly (72-31-00) - HPC
Borescope Inspection
CFM56-5B S/B 72-0781, Engine - General (72-00-00) - CFM56-5B Engine
Serialization Manufacturing Sequence
CFM56-5B S/B 72-0906, ENGINE - Compressor Front Stator Assembly (72-32-00)
- Introduction of New Stage 2 and Stage 3 Stator Shrouds, Stage 2 and Stage 3
Stator Seals, Stage 2 and 3 Bushings, and Retention Pin
J.
Publications Affected
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
Contact your CFM Customer Service Manager (CSM) for any removals due to
this Service Bulletin application.
C.
Configuration Chart
None.
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 5
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
D.
Parts Disposition
None.
E.
Tooling - Price and Availability
(1)
(2)
Fixtures, tools, test, and support equipment (use specified tools or equivalent):
Tool Number
Description
856A1084
Cart, Stator Actuator (actuator cart)
856A1321
Fiberscope Set
856A1322
Borescope - Lightsource Set
856A1323
Monitor, Resolution - Borescope
Optional Tooling:
Locally manufactured guide tube:
. Use a 0.3125 inch (7,938 mm) outer diameter (OD) plastic tube
approximately 7.0 inches (178 mm) in length. Bend the last 1.00 inch (25,4
mm) to a 30 degree angle.
3.
ACCOMPLISHMENT INSTRUCTIONS
A.
Flexible BSI of Forward Side of Stage 2 and Stage 3 HPC VSV Inner Shrouds
(1)
Do an inspection of the forward side of the stage 2 and stage 3 HPC VSV
inner shrouds. Refer to Figure 1 and do as follows:
NOTE 1:
It is necessary to do an inspection at the 3:00 and 9:00 o′clock
positions.
NOTE 2:
If the clearance between the trailing edge (TE) area of the blades
and the leading edge (LE) area of the HPC VSV inner shrouds is not
sufficient, a 4 mm flexible borescope is recommended.
NOTE 3:
The distance from the S3 stage 2 borescope plug and S4 stage 3
borescope plug ports over the 12:00 o′clock position to the 9:00 o′clock
position inspection area is approximately 39.0 inches (991 mm).
NOTE 4:
The conditions that follow are considered normal:
.
.
.
.
Wear/polishing on any honeycomb seal J-hook caused by contact
with the rotor, if not worn through
Missing metal on any honeycomb seal J-hook caused by contact
with the rotor, up to the length of one inner shroud
Wear on the inner lip of the HPC shroud
Misalignment between two adjacent HPC shrouds
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 6
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
.
Space (gap) between the honeycomb seal J-hook and the HPC
shroud rail
(a)
Use the resolution-borescope monitor to make sure that the fiberscope
set is serviceable.
(b)
Actuate the VSV system. Refer to the Airbus A318/A319/A320/A321
AMM, 72-31-00, Subtask 72-31-00-410-055, except actuate only until
the lever of the stage 3 VSV arms becomes parallel with the HPC case
split line.
(c)
Remove the S3 stage 2 borescope plug from stage 2, to do an inspection
of the clearance between TE area of the stage 2 rotor blades and LE
area of the stage 2 stator vanes. Remove the S4 stage 3 borescope
plug from stage 4, to do an inspection of the clearance between TE area
of the stage 3 rotor blades and LE area of the stage 3 stator vanes.
(d)
Connect the fiber light cable.
(e)
Insert the local manufactured guide (optional) into the borescope port
and turn it to point the flexible borescope between stage 2 or stage 3
stator vanes, in the direction of the TE area of the stage 2 or stage
3 rotor blades as follows:
(f)
1
Insert the flexible borescope probe and push it into the area forward
of the stage 2 or stage 3 stator vanes until it travels circumferentially
counterclockwise around the HPC flowpath, aft looking forward
(ALF).
2
The probe will go up over 3:00 o′clock position and bend around
over the 12:00 o′clock position, and then head down to past the 9:00
o′clock position. If possible, insert the scope in the clearance below
the TE area of the blade platforms to get a closer view. Because of
tolerance stack-ups, it might not be possible to insert the flex scope
into the clearance between the blades and vanes (Figure 2).
3
Articulate the scope to see the anti-rotation pins or seal rotation
as necessary.
For engines post-CFM56-5B S/B 72-0612 or post-CFM56-5B S/B
72-0672 and pre-CFM56-5B S/B 72-0906, while the flex scope is
removed from the area between the stage 2 or stage 3 stator vanes
and stage 2 or 3 rotor blades respectively, do a check for honeycomb
seal rotation as follows (Figure 2):
NOTE 1:
The anti-rotation pins are found approximately 0.50 inch
(12,7 mm) from the end of the shroud segments at the 3:00
and 9:00 o'clock positions (Figure 2).
NOTE 2:
The anti-rotation pins are found on the forward face of the
HPC shroud and are visible without entering the clearance
between the HPC blade TE and the LE of the HPC shroud.
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 7
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
NOTE 3:
There are four honeycomb seal segments and the
clearances will be found at the 3:00, 12:00, 9:00, and 6:00
o'clock positions.
NOTE 4:
The anti-rotation pin should be seated against the cutout
in the honeycomb seal. This cutout is approximately 0.670
inch (17,02 mm) on stage 2 and 0.765 inch (19,43 mm)
on stage 3 in length and can be used as an aid to find the
amount of honeycomb seal rotation. Refer to Figure 2.
NOTE 5:
The anti-rotation pin post-CFM56-5B S/B 72-0678 has
an approximate width of 0.166 inch (4,22 mm) and can
be used as an aid to find the amount of honeycomb seal
rotation. Refer to Figure 2.
NOTE 6:
The inspection specified in step 3.A.(1)(f) is applicable to
pre and post-CFM56-5B S/B 72-0678.
1
At the 3:00 and 9:00 o'clock positions, articulate the flex scope until
the anti-rotation pin on the forward side of the shroud comes into
view. Do an inspection of the anti-rotation pin to make sure that the
honeycomb seal has not rotated past this pin.
2
Make sure that the end of the honeycomb seal is aligned with the
end of the HPC shroud segment. Articulate the scope to make sure
that the alignment is correct.
3
Engine serviceability and reinspection intervals depend on the
amount of seal rotation as follows:
a
If the honeycomb seal is rotated less than 0.50 inch (12,7 mm)
beyond the end of the HPC shroud segment, the condition is
serviceable until the next recommended inspection specified in
paragraph 1.C., Compliance.
b
If the honeycomb seal has rotated between 0.50-0.90 inch
(12,7-22,7 mm) beyond the end of the HPC shroud segment,
do as follows:
c
1)
Do an HPC BSI of the stages 4 and 8 HPC blades. Refer to
the Airbus A318/A319/A320/A321 AMM, 72-31-00, TASK
72-31-00-290-002-A for procedures and serviceability
limits.
2)
If damage is found, do an inspection of the remaining
stages of the HPC blades.
3)
Reinspect for the amount of seal rotation at 1,600 plus or
minus 100 cycles.
If the honeycomb seal has rotated more than 0.90 inch (22,7
mm) beyond the end of the HPC shroud segment, do as follows:
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 8
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
(g)
1)
Do an HPC BSI of the stages 4 and 8 HPC blades. Refer to
the Airbus A318/A319/A320/A321 AMM, 72-31-00, TASK
72-31-00-290-002-A for procedures and serviceability
limits.
2)
If damage is found, do an inspection of the remaining
stages of the HPC blades.
3)
Remove the engine within 100 flight cycles.
For engines post-CFM56-5B S/B 72-0612 or post-CFM56-5B S/B
72-0672 and pre-CFM56-5B S/B 72-0906 with post-CFM56-5B S/B
72-0678 anti-rotation pins, while the flex scope is removed from the area
between the stage 3 stator vanes and stage 3 rotor blades, do a check
for slab headed anti-rotation pin rotation as follows (Figure 2):
NOTE 1:
The anti-rotation pins are found approximately 0.50 inch
(12,7 mm) from the end of the shroud segments at the 3:00
and 9:00 o'clock positions.
NOTE 2:
The anti-rotation pins are found on the forward face of the
HPC shroud and are visible without entering the clearance
between the HPC blade TE and the LE of the HPC shroud.
NOTE 3:
The anti-rotation pin should be seated against the cutout in
the honeycomb seal.
NOTE 4:
Inspection for engines with pre-CFM56-5B S/B 72-0678
is not necessary.
1
At the 3:00 and 9:00 o'clock positions, articulate the flex scope
until the anti-rotation pin on the forward side of the shroud comes
into view.
2
Engine serviceability and reinspection intervals depend on the
amount of pin rotation as follows:
a
If the slab headed pin has rotated less than 90 degrees, the
condition is serviceable until the next recommended inspection
specified in paragraph 1.C., Compliance.
b
If the slab headed pin has rotated 90 degrees or more, remove
the engine within 100 flight cycles.
c
If the slab headed pin is found missing, do as follows:
1)
September 04, 2015
Revision 03, October 30, 2018
Do an HPC BSI of the stages 4 and 8 HPC blades. Refer to
the Airbus A318/A319/A320/A321 AMM, 72-31-00, TASK
CFM56-5B S/B 72-0921
PAGE 9
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
72-31-00-290-002-A for procedures and serviceability
limits.
2)
If damage is found, do an inspection of the remaining
stages of the HPC blades.
3)
Remove the engine within 100 flight cycles.
(h)
Slowly pull the flex scope back out of the port after inspection is
complete.
(i)
Reinstall the S3 stage 2 borescope plug and the S4 stage 3 borescope
plug. Refer to the Airbus A318/A319/A320/A321 AMM, 72-31-00, TASK
72-31-00-290-002-A.
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 10
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
Flexible BSI
Figure 1
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 11
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
Borescope of Stage 3 VSV Anti-Rotation Pin
Figure 2, ( Sheet 1 of 4 )
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 12
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
Borescope of Stage 3 VSV Anti-Rotation Pin
Figure 2, ( Sheet 2 )
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 13
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
Borescope of Stage 3 VSV Anti-Rotation Pin
Figure 2, ( Sheet 3 )
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 14
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.
ENGINE - Compressor Front Stator Assembly (72-32-00) - On-Wing Borescope Inspection of
Metallic/Hybrid VSV System
Borescope of Stage 3 VSV Anti-Rotation Pin
Figure 2, ( Sheet 4 )
September 04, 2015
Revision 03, October 30, 2018
CFM56-5B S/B 72-0921
PAGE 15
CFM PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.