CFM Oil Scavenge Filter Bows Assembly

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CFM Oil Scavenge Filter Bows Assembly

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979199501

Arm Proposed Switch Configuration Current Double Throw Proposed Single Throw Run contact eliminated Introduction Logistics • CFMI/Boeing/Honeywell laun

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February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1
Oil Scavenge Filter Bows
Assembly
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2
Oil Scavenge Filter Bows Assembly
Background
• Numerous cases of Filter bowl found seized @ routine filter inspection
 Requires oil scavenge filter assembly replacement
Root cause
• Bowl / housing threads machining tolerances more tight on CFM56-3 design
compared to CFM56-7B
• CFM56-3 implemented on CFM56-7B design
 New configuration validated through successful component tests
• CFM56-7B configuration more prone to O-ring expansion due to higher oil
temperature
Damaged area
Damaged thread
Damaged
diameters
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3
Final Fix
• Bowl/housing thread machining tolerance like -3 design
– Concentricity tolerance more tight
– Interchangeability not affected
• Molykote grease on bowl thread at vendor and engine prod. level
 Both changes
– Implemented on production engine since Dec 2001
– SB 79-0006 will be released in Feb 2002
• New seal (O-ring) design
 Smaller Viton O’ring seal selected
– Same tore diameter, and smaller inner diameter (less expansion)
 O-ring seal J221P238 replaces J221P239
 SB release expected in Feb 2002
 Also will be introduced in CFM56-3 IPC as alternate with current O-ring
Oil Scavenge Filter Bows Assembly
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4
Field Recommendation
• Compliance with AMM procedure reduces damage risks
 Clean threads and mating diameter
 Install Filter Cartridge in the housing prior to bowl installation
 Apply grease on bowl threads only
 Hand tighten the bowl
 Apply symmetrical force to bowl at removal
• Use anti-seize compound only (Molykote Paste CP2569, CP2104,
CP2444)
 DO NOT use graphite grease
 Apply on bowl threads only (ref AMM 79-21-06/401)
Oil Scavenge Filter Bows Assembly