标题: Aft Engine Mount Center Link Orientation [打印本页] 作者: 航空 时间: 2011-4-12 23:21:21 标题: Aft Engine Mount Center Link Orientation
作者: 航空 时间: 2011-4-12 23:21:39
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1 Aft Engine Mount Center Link Orientation February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2 Aft Engine Mount Center Link Orientation Event Summary • One operator reported center link assembly, P/N 310A2034-3, found installed reversed on one airplane Occurred during overhaul of aft engine mount and not noted during aft mount installation on engine Center link pawl pins requiring some effort to install No difficulties in engine installation on airplane noted Further investigation revealed 5 other cases of reversed center link on operator’s fleet • Second operator advised Boeing of difficulty in closing thrust reversers after No. 2 engine installation All mounts were found properly mating with strut Engine had undergone post installation engine runs with no anomalies Engine was found to be rotated slightly outboard (right) Engine was lowered, and inspection revealed center link, P/N 310A2034-7, was reversed February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3 Aft Engine Mount Center Link Orientation No. 1 Outboard Location (Correct Installation) No. 2 Outboard Location (Incorrect Installation) February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4 Aft Engine Mount Center Link Orientation Background • Center link is boomerang-shaped, attaches to hanger fitting in center and engine lugs at either side • Link almost symmetrical left-to-right • Installed spherical bearings almost identical in size Difference in bearing bore diameter (1.00 inch versus 1.185 inch) not always apparent Smaller left bearing and pin are primary load path Larger right bearing and pin are fail safe load path. Not normally loaded due to clearance fit Result: Link can be installed reversed in aft mount using existing pawl pins Shifts aft end of engine 0.174-inch to right February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5 Aft Engine Mount Center Link Orientation Background (cont) • Condition applies to the following aft engine mounts: P/N 310A2034-3 Center Link installed on P/N 310A2030-6 Aft Engine Mount P/N 310A2034-7 Center Link installed on P/N 310A2030-11 Aft Engine Mount (SAC) P/N 310A2034-8 Center Link installed on P/N 310A2030-12 Aft Engine Mount (DAC) Could be installed on any 737NG-series airplane Status • Reversed center link results in out-of-compliance configuration • If condition is suspected, visual inspection can be used to check orientation If condition is confirmed, corrective action must be performed prior to further flight • The following documents were revised to further clarify existing installation: AMM 71-21-03/401 12 February 2002 Revision PPBU Figure 3-1 5 February 2002 Revision CMM 71-21-37 1 March 2002 Revision • More information found in following: FLEET TEAM Digest Article 737ng-FTD-71-01003, dated 20 Dec 2001 Boeing Service Letter to be released shortly (late Jan/early Feb) February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6 Aft Engine Mount Center Link Orientation Recommendations • Ensure that the center link is installed correctly in aft mount after overhaul • During aft mount installation on engine, ensure no preload is required to install either of four pawl pins securing center link and side links to engine lugs • Make sure no excessive force is necessary to close the thrust reversers作者: kinran 时间: 2011-6-4 23:32:46
