February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1 CFM56-7 HMU FMV / Resolvers February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2 CFM56-7 HMU FMV / Resolvers February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3 FMV Related Faults • FMV faults have become leading cause of D&Cs in -7B fleet - Fault codes 73-x034y, 73-x035y (x=Channel, y=Engine position) - Faults result in Engine Control Light indication in cockpit - Driving 10 HMU removals per month - No operational events • Extensive root cause investigation on-going - Analysis, component, systems rig testing • Design and manufacturing process changes are being incorporated to address identified failure modes • Additional changes for improved reliability being defined, evaluated and tested - Design, manufacturing, software logic February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4 • HMU and resolver analytical efforts - Tolerance studies, loads, modal, thermal effects including finite element analysis • HMU Testing at Burbank - Run-as-received, electrical checks, inspections (wires, binding, wobble) • Resolver Module Testing at Kearfott - Room temperature electrical tests and thermal cycling (all) - “Shake & bake” testing (10 units) - no failures observed - Wire disassembly of unconfirmed units (7) - 2 rubbed rotors observed FMV Root Cause Investigation - Scope February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5 • Systems level testing on CFMI systems rig - Focus on unconfirmed units - Allows monitoring of individual windings and EEC faults • HMU / Resolver Module Testing at Honeywell - South Bend - Cell 8 rig test temperature and FMV cycling - 11 units - Vibe testing for intermittent opens / shorts - 26 units - Thermal and moisture tests of resolvers to check for shorts - 13 units - Load testing for channel disagree faults - 2 units FMV Root Cause Investigation - Scope February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6 FMV Root Cause Investigation - Findings • Fault confirmation rate currently 42% - 74% resolver, 26% HMU-related • Fault tree analysis used to identify 70 possible failure contributors - 65 of these have been investigated • Design and process improvements incorporated for 11 of 12 failure modes identified to date - Implemented in new production and field return units following introduction 42% 58% 74% 26% Unconfirmed Confirmed Resolver HMU February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 7 0 2 4 6 8 10 12 14 16 Rotor Winging Open Lamination Damage/Binding Stator Termination Failure Sator Winding Open Insulation Resistance Rotor Termination Failure Resolver Position Adjusted Wire Chafing High Eng Play Bent Connector Pin Mis-pinned Connector FMV Extension Wobble End Play Stator Termination Rotor Opens in Winding and Near Termination Stator Winding Open Low Insulation Resistance Resolver Schematic Resolver Failure Pareto FMV Root Cause Investigation - Findings • Majority of resolver failures related to wiring issues - Quality and position adjustment lessor contributors • “Rotor winding open” to be addressed 2Q’02 - Improved strain relief at termination - Wire gauge increase from 43 to 42 …currently being tested Corrective Action in Process Corrective Action In Place No Corrective Action Defined February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 8 • Corrective actions expected to address some but not all unconfirmed units (58%) - Non-resolver related problems suspected as majority of unconfirmed population……..linkage, system stackup • FMV linkage evaluations in process: - Resolver ball hangup due to potential geometric stackup issue - FVM extension wobble due to side loading of extension - High friction/clamping force on ball follower due to wear • Systems level analysis (Engine Control, HMU, wiring) being performed to insure compatibility - Potential cause for “out-of-range” faults - Plans for acquiring EEC NVM data to support investigation are being developed • Additional changes being considered for improved reliability: - Improved software accommodation logic - Larger diameter wires (>42 gage) in resolver and resolver housing change FMV Root Cause Investigation - Findings作者: kinran 时间: 2011-6-4 23:12:27
