EGT Harness Contamination
**** Hidden Message ***** EGT Harness<BR>Contamination<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 2<BR>• D&C’s due to EGT indication 50-100°C lower than<BR>adjacent engine<BR>- Drift down occurs gradually over a 2-3 week period<BR>- Confirmed by trend monitoring<BR>Fleet Experience<BR>EGT drift FF / VSV / N2 stable<BR>3 weeks<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 3<BR>• Anomaly corrected by replacement of lower, higher or<BR>junction box harness<BR>- Faulty harness detected per on-wing AMM inspection/check 77-<BR>21-10-601<BR>• Low time occurrence failure mode:<BR>- Drift down reported on first run engines below 3000 hours<BR>All Engines Over 3000 Hours<BR>Not Affected by EGT Indication Drift<BR>Fleet Experience<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 4<BR>Investigation<BR>• Electrical test...insulation resistance discrepancies<BR>- Low insulation resistance or short circuit between Cr/Al wires<BR>- Consistent with EGT signal drift down<BR>• Harness strip down...black deposit contamination<BR>inside glass sealing at con o ’clad tip area<BR>- Extensive quality audit conduced at Auxitrol<BR>- Root cause of contamination identified<BR>- Poor piece part cleaning after machining operation at<BR>subcontractor level<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 5<BR>Contaminant Location<BR>Contaminant location<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 6<BR>Corrective Actions<BR>• Production level<BR>- Ultrasonic cleaning with appropriate solvent<BR>implemented from Jan. 2002<BR>- Engine ESN introduction<BR>- CFM56-5B/P SAC, 575383<BR>- CFM56-5B/2P DAC, 575910<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 7<BR>• Suspect harness population defined<BR>- Harnesses produced from Sept. 98 to Dec. 01<BR>• SB 77-0006 (-5B), cat 4, released Aug 2001:<BR>- For affected -5B engines below 3000FH<BR>- Detection of gradual EGT drift down through the<BR>current EGT trend monitoring<BR>- Crew observation of EGT mismatch<BR>- AMM 77-21-10-601 inspection and replacement of<BR>faulty harness<BR>- Revision 1 targeted end May 2002<BR>Field Recommendations<BR>CFM56 Operators Conference – May 21 - 22, 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 8<BR>Field Recommendations<BR>• S/B 77-0008 (-5B), cat 1, to track/replace EGT<BR>harnesses delivered by Vendor as LRU spare parts<BR>- For harnesses having cumulated less than 3000FH<BR>- Replacement of identified LRU spare parts according to<BR>Vendor list<BR>- To be mandated by Agencies<BR>- Issued March 2002<BR>• Field contaminated harnesses replaced/reworked at no<BR>cost by the Vendor :victory: :victory: EGT Harness Contamination EGT Harness Contamination
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