Best Practices Optimizing CFM56 Bearing Care ( core engine bearings focused )
**** Hidden Message ***** April, 00 Rev. A - Prelim 1CFMI Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited.
Best Practices
Optimizing CFM56 Bearing Care
( core engine bearings focused )
April, 00 Rev. A - Prelim 2
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OVERVIEW
– Why / How
• observations
• actions
• documents
– Do / Do not
• engine level
• shop level
• #4 bearing level
• test level
– Self assessment check-list
– Appended sketches and photos
April, 00 Rev. A - Prelim 3
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• CFMI observations :
Reliability
(12 month rolling averages ) :
• #1, #2, #5 bearings << 0.1 per million EFH
• # 3 bearing failure rate 0.3 per million EFH
• # 4 bearing failure rate 1.4 per million EFH
• gearboxes bearing failures case-by-case considered
- ----> Focus: #3 and #4 bearing
Prevalent
failure causes :
• # 3 bearing -----> hard particle contamination
• #4 bearing -----> outer race spalling
- no "prime" aggressor identified
- ---> every aggressor targeted
Major
aggressors to address :
• contamination
• corrosion (moisture)
• impacts
- transportation
- handling
- assembly
April, 00 Rev. A - Prelim 4
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• Actions
• Increase resistance to aggressor
• manufacturer
• Minimize "aggressors"
• manufacturer
• airline
• overhaul
• Documents
• Best practices
• chronological list for "off-wing" good practices
• includes self-assessment check-list
• Memorandum -CESM- 3rd quarter 1999
CFM56-3 No. 054
CFM56-5A No. 029
CFM56-5B No. 008
CFM56-5C No. 009
April, 00 Rev. A - Prelim 5
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tools
workstations
processes
engine
transportation
cleanliness &
organization
modules and bearings
handling/ protection / storage
assembly
engine
storage & preservation
Best environment for
bearings reliability
stands
covers & plugs
consumables
SHOP & LINE
SHOP
training
April, 00 Rev. A - Prelim 6
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RISKS
DO
Ref.
- Moisture in sumps / wetting of bearing hardware
- Corrosion
- Use :
Corrosion inhibitors in oil
Covers / canvas / plugs
Bags of desiccant
- Respect intervals :
1 month / 3 months / 1 year
- Apply :
Drain instructions
Oil circuit preservation
Dry-out / relube after an IFSD
- Store engine in humid/salty/dusty areas
- Leave ports / openings unplugged
STORAGE (engine)
Aircraft Maintenance Manual , section 71-00-03 or 72-00-00
Appended sketches
DO NOT
April, 00 Rev. A - Prelim 7
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DO
Ref.
TRANSPORTATION
(engine)
- Brinelling of bearing races
- Use approved cradle / stands / dollies
- Check condition of :
dampers
pins / clevis
- Tie down stand base to trailer bed
- Use pneumatic suspension trucks
- Check transportation and storage
container condition before shipping
- Use non-conformed / modified devices
- Tie down cradle directly to trailer bed
- Aircraft Maintenance Manual , section 71-00-04 or 05-xx-xx
- Appended sketches
RISKS
DO NOT
April, 00 Rev. A - Prelim 8
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RISKS
DO
Ref.
SHOP organization :
workstation - Contamination : abrasives media, hard particles
- Work beside :
• machining areas (grinding)
• abrasive tools (wheels, stones)
• airborne abrasives (fan)
- Store parts on/near ScotchBrite® pads
- Use ScotchBrite® pads around bearing
assembly areas
- Use cleanable and cleaned work table
- Use disposable craft paper
Appended photos
DO NOT
April, 00 Rev. A - Prelim 9
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RISKS
DO
Ref.
SHOP organization :
bearing handling - Hard particle transfer to bearing
- Corrosion (sweat, moisture)
- Use clean gloves
• white lint-free for inspection
• rubber for cleaning
• thermal : keep separate, covered
and clean (for bearing specific use
only) .
- Use dedicated oven for heating
parts / tooling
- Perform cleaning / blending of parts
with abrasives / ScotchBrite® in areas
where bearings are exposed
Appended photos
DO NOT
April, 00 Rev. A - Prelim 10
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RISKS
DO
Ref.
SHOP organization :
bearing protection
- Hard particle transfer to bearing (airborne, contact)
- Moisture --> corrosion
- Impacts
- Use protections:
• grease-proof barrier paper
• plastic film (#4 bearing inner race on LPT shaft)
• aluminum sheet
• bubble paper
• clean, covered, dedicated storage box (for
wrapped #4 brg. outer race)
- Minimize the #4 bearing exposures
during inspection -cleaning - storage cycle
--> remove outer race from HPT rear shaft /
protect immediately after LPT module removal
--> wrap inner race in plastic film
- Leave bearings packed-protected until
last minute / ready to install
- Leave #4 bearing unprotected :
• outer race in HPT shaft
• inner race assy. on LPT shaft
DO NOT
Engine Shop Manual 72-00-52, 72-00-03
Appended photos
April, 00 Rev. A - Prelim 11
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RISKS
DO
Ref.
SHOP organization :
bearing adjacent parts care - Hard particle transfer to bearing
- Keep clean sumps and pipes
- Plug pipes / housing ports / nipples
- Cover frame openings
- Use clean covers (caps/plugs/canvas)
- Schedule maintenance of sets of
covers (cleaning, reprovisioning)
- Check for cleanliness
• IGB housing
• Fan Frame
• (TRF) rear cover
- Blend in-situ without protection / masking
(frames / supports / brackets...)
- Use unproved plugs / covers...
- Store tubes in "bunches" / in the
unplugged condition .
DO NOT
April, 00 Rev. A - Prelim 12
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RISKS
DO
Ref.
SHOP organization :
tooling condition survey - Transfer particles to bearings
- Scores and marks
DO NOT
- Keep clean tooling that contacts
bearings :
• wipe with alcohol before use
• store in clean container
- Periodically check tooling for:
• cleanliness
• magnetization
• retractable fingers condition
Appended photos
April, 00 Rev. A - Prelim 13
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RISKS
DO DO NOT
Ref.
SHOP organization
cleaning & coating, fluids - Hard particle contaminating fluids-->bearing
- Corrosion
Cleaning
- Filter cleaning bath 10 microns
- Maintain tanks and baths
check deposits --> flush
periodically :
- flush isopropyl alcohol bath
(hydroscopic)
- replace filters
Coating
- Use one master can for oil &
one master can for grease to fill :
- sister oil pipette
- sister grease (and fonolene) tin
( wash before every refilling )
- Clean brand new bearings (ready to use)
April, 00 Rev. A - Prelim 14
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RISKS
DO DO NOT
Ref.
SHOP organization
Miscellaneous
- Hard particle capture (magnetization)
- Brinelling
- Corrosion
- Contamination
- Check magnetism with gaussmeter
- Demagnetize bearing
- Use dampened trucks / dollies
- Cover parts / sumps for work-stoppage
(for more than 1 hour delay )
- Carry / store by electrical fields
(take caution of electric trucks / stations)
- Use rigid axled trucks (bumps, vibrations)
Appended photos
Engine Shop Manual 72-09-01
April, 00 Rev. A - Prelim 15
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RISKS
DO DO NOT
Ref.
SHOP organization :
training
- Contamination
- Corrosion
- Handling / installation faults
- Schedule training for new personnel
- Periodic re-training
- Provide new personnel with the support
of experienced personnel
- Allow non-trained mechanics to install
the LPT module
April, 00 Rev. A - Prelim 16
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RISKS
DO DO NOT
Ref.
SHOP organization :
cleaning / inspection / storage
"cycle"
- clean immediately before inspection
- preserve immediately after inspection
- Corrosion
- Contamination
- Apply proper storage process / corrosion prevention
products
• short term : MIL-L-6085
• long term :MIL-C-11796 class.3
• no further depreservation needed
- pack components individually , then as a set (#4 brg.)
- cover stored components
- separate matched sets
(roller bearings)
- allow metal to metal
contact for stored parts
Engine Shop Manual 72-09-01
Appended photos
April, 00 Rev. A - Prelim 17
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RISKS
DO DO NOT
Ref.
#4 bearing :
inner race
installation
- race mismating LPT shaft
- particles entering cage pockets
- heat race with assembly tool
- check actual temperature (150°C)
of race with thermometer
- use dedicated clean thermal gloves
- store gloves separately
- wrap in triple 360° plastic film when cool (~40°C)
(allowed only for shop conditions)
- use anything other than
dedicated gloves
- leave inner race unprotected
Appended photos
Engine Shop Manual 72-55-00
April, 00 Rev. A - Prelim 18
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RISKS
DO
DO NOT
Ref.
#4 bearing :
outer race installation
- mismatching inner-outer bearing races
- misinstallation
- corrosion, particles
- check races pairing (same S/N)
- rotate heating tooling for constant
temperature distribution
- check actual temperature (170°C)
of HPT rear shaft with thermometer
at two locations
- grease / oil using dedicated tin / bottle
- use dedicated clean thermal gloves
- store gloves separately
- torque nut while still hot and
fit lock ring immediately
- plug cooling holes with excess grease
- use anything other than dedicated :
• oil and grease containers
• gloves
Appended photos
Engine Shop Manual 72-00-52
April, 00 Rev. A - Prelim 19
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RISKS
DO DO NOT
Ref.
#4 bearing :
LPT module installation
- rollers / outer race impact
- stresses
- use scale between hook and hoist
- use level gages
- use centering tool
- preset LPT rotor forward
- oil outer race & use fonolene to retain rollers
- make a trail fit of module
- check actual outer race temperature at two
locations (12:00 and 6:00)
- approach slowly with 2 stops
- rotate fan while pulling/screwing LPT shaft / nut
- complete procedure within 5 min. after
temperature check
- work with no scale/level gages
- let parts cool down
- shake LPT module to help fit
- forget fan rotation
- leave excess fonolene forward
of the rollers and cage
- adjust CG fixture after stops
have been removed
(when bearing rollers are
engaged in outer race)
Engine Shop Manual section 72-00-03
Appended photos
April, 00 Rev. A - Prelim 20
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RISKS
DO
DO NOT
Ref.
Engine Test - damaged bearing release
- contamination
- prime oil supply lines with oil before test
- check MCD (ECD , DMS) after test
- install a brand new supply filter after test
- use recycled oil
April, 00 Rev. A - Prelim 21
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Check-list
Category Activity or Shop Practice Yes No Comment Impact
Storage Is engine oil circuit preserved (inhibitors) for long/short term storage? High
Are approved corrosion inhibitors used? High
Is an approved dry-out procedure applied after a water wash? Med.
Are covers used on modules and containers? / Condition controlled? High
Are bags of desiccant used? Med.
Is storage planning documented and controlled? High
Are engines dried-out / relubed after an IFSD? Med.
Module
Transportation
Do all cradles conform to tiedown and shock absorption
requirements with control by periodic review?
Qty accounted for: Med.
And Handling Do all shipping stands conform to tiedown and shock absorption
requirements with control by periodic review?
Qty accounted for: Med.
Is damper/shock absorber condition checked before shipping? Low
Is cradle tie-down condition checked before shipping? High
Shop Are worktables clean? Periodic thorough cleaning planned? High
Organization Are work and storage areas isolated from airborne abrasives? Med.
Are grinding operations in a separate room? Med.
Are ScotchBrite pads banned from the assembly and handling
areas?
Med.
Are protective shields used when doing in-situ blending or rework? High
Are inspection gloves clean? High
Is rubber handling gloves clean? Med.
Are insulated thermal gloves clean and dedicated to bearing assembly
uses only?
Qty accounted for: High
Is barrier paper or film used to protect the #4 bearing after installation? High
Is bubble paper/wrap used for bearing packing? Med.
Are clean and dedicated boxes used for the #4 bearing outer race? Qty accounted for: Med.
Are there periodic cleanliness checks of sumps and pipes? High
Are frame openings covered? Med.
Are ports and pipes plugged on modules and component hardware? High
Are plug sets maintained in place until actual mating part is attached? High
Are there periodic IGB housing / Fan Frame / Rear cover cleanliness
checks?
Med.
Does the shop have a periodic tool-cleaning schedule? Med.
Are clean sealed containers used for tools used in contact with or in
close proximity to bearings?
Med.
April, 00 Rev. A - Prelim 22
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Check-list
C a te g o ry A c tiv ity o r S h o p P ra c tic e Y e s N o C om m e n t Im p a c t
D o p ro c e d u re s in c lu d e w ip in g / c le a n in g to o ls in c o n ta c t w ith b e a rin g s ? H ig h
Is th e re p e rio d ic to o l m a g n e tiz a tio n c h e c k ? M e d .
A re c le a n in g b a th flu id s filte re d b e fo re u s e o r d u rin g re c irc u la tio n ? M e d .
Is th e re a p e rio d ic flu s h o f c le a n in g b a th s ? M e d .
A re o il b o ttle s a n d g re a s e tin s c le a n a n d d e d ic a te d to b e a rin g
a s s em b ly ?
L ow
Is a b e a rin g m a g n e tiz a tio n c h e c k p e rfo rm e d p rio r to a s s em b ly ? H ig h
R ig id a x le / u n d am p e n e d tru c k s a b s e n t from a s s em b ly a n d s h ip p in g ? L ow
E le c ./M a g . fie ld s a b s e n t from b e a rin g w o rk , s to ra g e a n d
tra n s p o rta tio n a re a s ?
M e d .
D o te c h n ic ia n /m e c h a n ic s h a v e in itia l b e a rin g a s s em b ly tra in in g ? H ig h
D o te c h n ic ia n /m e c h a n ic s h a v e p e rio d ic re tra in in g o n b e a rin g is s u e s ? M e d .
A re b e a rin g s im m e d ia te ly in s p e c te d a fte r c le a n in g ? H ig h
A re b e a rin g s im m e d ia te ly p re s e rv e d a fte r in s p e c tio n ? H ig h
D o a ll s to ra g e p ro d u c ts , p a c k a g e s , s e a lin g c o n fo rm to c le a n lin e s s
n e e d s ?
H ig h
# 4 B e a rin g
In s ta lla tio n
A re in s u la te d th e rm a l g lo v e s c le a n a n d d e d ic a te d to b e a rin g a s s em b ly
u s e s o n ly ?
H ig h
Is th e in n e r ra c e a c tu a l tem p e ra tu re c h e c k e d ? M e d .
Is th e in n e r ra c e w ra p p e d a fte r in s ta lla tio n (a fte r c o o l d ow n )? M e d .
Is th e o u te r ra c e / in n e r ra c e p a ir c h e c k e d fo r s e ria l n um b e r m a tc h ? H ig h
A re o il b o ttle s a n d g re a s e tin s c le a n a n d d e d ic a te d to b e a rin g
a s s em b ly ?
M e d .
Is o u te r ra c e re ta in in g n u t to rq u e d w h ile s till h o t? L ow
# 4 B e a rin g / Is th e s c a le u s e d a n d w a tc h e d b e tw e e n h o o k a n d h o is t? H ig h
LP T In s ta lla tio n A re le v e l g a g e s u s e d to e n s u re a lig nm e n t (H PC / LP T fla n g e s p a ra lle l)? H ig h
Is th e p ro p e r c e n te rin g to o lin g u s e d ? H ig h
IS H P /LP m o d u le s tra il fit p rio r to fin a l a s s em b ly ? H ig h
Is th e o u te r ra c e a c tu a l tem p e ra tu re c h e c k e d ? H ig h
Is th e LP m o d u le in s e rte d w ith a p ro g re s s iv e s low a p p ro a c h ? H ig h
Is th e fa n ro ta te d d u rin g LP T p u llin g ? H ig h
Is fin a l c o u p lin g c om p le te d w ith in 1 0m in . o f th e o u te r ra c e /s h a ft
tem p e ra tu re c h e c k ?
H ig h
T e s t Is n ew , n o n -re c y c le d , c le a n o il u s e d in fillin g th e ta n k (filte re d if b u lk )? H ig h
Is th e M C D (E C D /DM S ) c h e c k e d a fte r te s t? H ig h
April, 00 Rev. A - Prelim 23
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( shipping stand and base )
April, 00 Rev. A - Prelim 24
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( road transportation )
pneumatic shock absorbers
tie down of stand base on trailer bed
April, 00 Rev. A - Prelim 25
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(sumps relubrication device)
April, 00 Rev. A - Prelim 26
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(dry-out of engine after an IFSD)
April, 00 Rev. A - Prelim 27
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#4 bearing inner race packing
Photo .JPEG - Bp26(1-5)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 28
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#4 bearing inner race installation
Photo .JPEG - Bp27(2-9)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 29
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(LPT, shop only) inner race protective film
Photo .JPEG - Bp28(11-4)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 30
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LPT module protection in shop
Photo .JPEG - Bp29(11-6)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 31
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#4 bearing outer race magnetization check
Photo .JPEG - Bp30(6-12)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 32
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Tooling cleaning ( #4 bearing outer race nut installation tooling)
Photo .JPEG - Bp31(8-8)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 33
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#4 bearing outer race retaining nut installation
Photo .JPEG - Bp32(7-7)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 34
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Core module (vertical aft flange) adjustment
Photo .JPEG - Bp33(3-10)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 35
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LPT module (vertical fwd flange) adjustment
Photo .JPEG - Bp34(3-7)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 36
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Installing LPT module ; scale between hook and hoist
Photo .JPEG - Bp35(3-3)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 37
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Actual temperature checks ; HPT rear shaft / #4 bearing outer race
Photo .JPEG - Bp 36(7-6)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 38
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LPT module progressive approach
Photo .JPEG - Bp37(10-2)
#4 bearing / LPT module installation specifics
April, 00 Rev. A - Prelim 39
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LPTmodule coasting ; Fan rotation / screwing LPT module coupling nut
Photo .JPEG - Bp38(10-6)
#4 bearing / LPT module installation specifics 撒打算打算
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