CFM Components & Accessories Accessory GearBox Links Bearing Wear

航空发表于 2011-4-23 10:42:07

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航空发表于 2011-4-23 10:42:20

CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1 Accessory GearBox Links Bearing Wear Components & Accessories CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2 Background • Several reported AGB links bearings severely worn on CFM56-7B engines  CFM56-3 also affected to a lesser extend • 3 parts involved:  upper non-adjustable link:  bearings damaged on both ends of the link  no measurable longitudinal displacement  “worst case” highly worn bearing  axial 3-5 mm  not received yet  lower non-adjustable link:  no wear reported  adjustable link:  similar axial wear reported on 30% of inspected engines Components & Accessories AGB Link Wear Axial CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3 VVeerryylilmimititeeddlolonnggitituuddininaallddisispplalacceemmeenntt//HHigighhaaxxiaiallddisispplalacceemmeenntt Self Lubricating Feature Wear longitudinal axial link Spherical Bearing External Link inner surface Components & Accessories AGB Link Wear CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4 Engineering assessment • Phenomenon/ root cause:  wear induced by engine vibration  Link retaining feature loaded by link weight  Self lubricating feature degradation • Consistency of root cause:  Angular work combined with link weight leading to Bearing degradation  horizontal upper non-adjustable link most damaged • Effect of wear:  effect on AGB position acceptable  heavy bearing axial wear may lead to contact between Link, and AGB Hinge Fitting wear (not experienced yet) – Axial wear to be limited to 1.3 mm  longitudinal wear would impact AGB mounting system vibrations damping capability – Longitudinal wear to be limited to 0.2 mm Components & Accessories AGB Link Wear CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5 Corrective Action Plan • Further investigations on “worst case”  When parts received Oct, 02 • AMM limits proposal  Any amount until the Link FWD edge is in contact with the ABG Hinge Fitting – Maximal authorized wear covered by the Link / Fitting gap – Measurement in this environment seems not easy  If the link in contact with the Hinge an overserviceability of 500 cycles is allowed • Short term containment Field Plan  Temporary repair by implementation of RTV – 3 RTV types are proposed depending of the available curing time – RTV injection between link and AGB Hinge Fitting to set the link in the proper position and support it’s weight under vibration – Implementation through CDR (Already applied in field) Components & Accessories CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6 Corrective Action Plan (cont’d) • Mid term Field Plan :  Fit check exercize at the training school was performed to validate the Upper Link replacement on-wing – Different Upper Link dimensions have been tested  Drawing Link longitudinal tolerance is +/- 0.3 mm [+/- 0.012”]  Mechanic was able to install a link within 0,2 mm of the removed one.  Impossible to install a link at the Max. tolerance value – The replacement of the link on-wing will not be implemented in the AMM  Link Repair – Bearing replacement procedure in process – will be a generic repair for all bearings December, 02 Components & Accessories AGB Link Wear CFM56-7B WTT Meeting - September,26-27/2002 CFM / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 7 Corrective Action Plan (cont’d) Final fix Plan  Different solution under study – Removable Spherical Bearings  Review with the proposed vendor completed  One bearing definition has been identified  Installation study to be performed – Introduction of a Teflon washer – Introduction of a bigger Spherical Bearing  Final Fix selection December,02 Components & Accessories AGB Link Wear

kinran 发表于 2011-6-4 22:58:17

:victory: :victory:

bocome 发表于 2011-7-31 05:12:45

CFM Components & Accessories Accessory GearBox Links Bearing Wear

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CFM Components & Accessories Accessory GearBox Links Bearing Wear