标题: Ignition System Reliability [打印本页] 作者: 航空 时间: 2011-4-12 23:25:07 标题: Ignition System Reliability
作者: 航空 时间: 2011-4-12 23:25:32
CFMI Proprietary Information 13.1 Ignition System Reliability CFMI Proprietary Information The information (including technical data) contained in this document is the property of CFMI. It is disclosed in confidence and the technical data therein is exported under a U.S. Government license GTDR. Therefore, none of the information may be disclosed to other than the recipient, or used for purposes other than to render services to CFMI, without the express prior written authorization of CFMI. In addition, the technical data therein, and the direct product of the data, may not be diverted, transferred, re-exported, or disclosed in any manner not provided for by the license without prior written approval of the U.S. Government. CFMI Proprietary Information 13.2 Overview • Fleet Experience • Hardware Improvements • Maintenance Recommendations • Summary CFMI Proprietary Information 13.3 Fleet Experience • Ignition system is one of the top causes of delays and cancellations on the CFM56-3 engine program • Ignition system reliability has been improving with increased awareness and new hardware CFMI Proprietary Information 13.4 Hardware Status • “Murphy-proof” leads have shown significant improvement - Reduced pitting and arcing at contacts - Fewer misassembly errors • New failure mode has been seen on new “Murphy-proof” leads - Inner seal failure resulting in electrical energy arcing from the contact to the inner spring assembly - Design changes are being evaluated CFMI Proprietary Information 13.5 Hardware Status Original Type 4 Ignition Lead with WHITE silicone seal CFMI Proprietary Information 13.6 Hardware Status “Murphy Proof” Lead with BLUE silicone seal CFMI Proprietary Information 13.7 Maintenance Recommendations • Replace ignition lead outer seal whenever the lead-to-plug connection is separated - Degradation of seal results in inability to reseal the interface - Note the seal is not interchangeable between the new (blue) and old (white) Type 4 leads • Polish the contacts when the lead-to-plug connection is separated - Unremoved pitting can lead to premature failure of both igniter and lead - Polishing tools available for the lead contact - Unison tool kit P/N 11-10786-1 or P/N 137356 - Use 3/8” medium grit abrasive impregnated rubber rod (Craytex or local purchase) for igniter plug contact surface CFMI Proprietary Information 13.8 Maintenance Recommendations Unison Contact Polishing Kit CFMI Proprietary Information 13.9 Maintenance Recommendations Apply Grease DO NOT Apply Grease to these threads Igniter Plug Maintenance CFMI Proprietary Information 13.10 Maintenance Recommendations (Continued) • Ignition component "soft-time" - Study performed 1st Quarter 1993 - Airline input and experience considered - Lead considered to be the major problem - Exciter replaced to move aircraft although rarely the problem - Plugs are also cause of engine no-starts - 2,000-cycle replacement on lead provided alternating ignition is used - 1,000-cycle replacement on plug (low energy) - CESM 005 updated to reflect “remove and replace” soft time recommendation CFMI Proprietary Information 13.11 Summary • Improper maintenance is still seen with original Type 4 lead - Incorrect assembly or missing hardware - Antiseize grease applied or not applied to proper locations • New hardware improvements have proven to add life and increase reliability of the entire ignition system - Individual operators are reporting significant improvements with new hardware - Additional changes are being reviewed • Unison has published a pocket-size Type 4 Ignition Troubleshooting Guide CFMI Proprietary Information 13.12 Summary (Continued) • Operators are encouraged to incorporate hardware improvements and/or "soft-time" replacement intervals on older hardware • Boeing has a Master Change available which provides a kit of hardware and instructions to transfer the power supply from the aircraft standby BUS to reach the left exciter while the right hand side is inoperative - The MMEL has been revised to allow dispatch with RH system INOP provided the operator has an approved configuration for the LH system to be powered by the aircraft BUS • Dispatch reliability has exceeded 99.95% since mid-1994 and is expected to continue to improve作者: show616 时间: 2011-4-13 09:49:51
