CFM Ignition System Reliability

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February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1
Ignition System Reliability
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2
Ignition System Reliability
• Ignition System is third leading cause of D&Cs
- Behind HMU HPSOV switches and FMV faults
- Includes A/C start brake assembly, A/C and engine harnesses, EEC,
exciter, lead and plug
- Engine hardware excluding plugs continues to be No Fault Found
• CFMI and Boeing studied 117 Event Reports (1-98 to 7-00)
- 58 of these events resulted in D&Cs
• Data typically insufficient for exact causal determination
- Squawks were intermittent, no follow up reports, plug time not tracked
• Based on the E/R narrative and a predetermined set of ground rules, the team
assigned cause as:
- Ignitor plug
- A/C switch (start brake)
- Can’t determine
- Other
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3
Potential Improvement Areas for Ignition System Dispatch Reliability
• Improved Troubleshooting EEC SW version 7.B.M1
- FIM procedure 80-06, tasks 801 through 805
• Use of Input Monitoring to determine if switches are in commanded state
D & Cs by Ignition Side
Right
Left 57%
23%
Can't Tell
16%
Both
4%
Breakdown of Ignition SystemD&C's
Suspect Plug
27%
Suspect Switch
33%
Can't Tell
22%
Other
18% Ignition D&C Repeats
D&C Repeat
16%
No D&C
Repeat
84%
Ignition System Reliability
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4
Potential Improvement Areas for Ignition System Dispatch Reliability
• Plug Soft Time
- Significant improvement, recommend 1000 cyc (CESM 006, revision 3)
• Plug costs ~ 25¢ per engine cycle vs thousands of dollars per D&C
- Unison offers a service to its customers to determine if there is
significant life remaining on igniter plugs (FEB-2002 FHA)
• Adjust soft time depending on results
• For $9 per plug, part will be assessed for life remaining
» If 50% or more life remains, plug will be returned to customer
» If less than 50% life remains, part will be scrapped
• Send plugs only in groups of 25 or more to
» P.O. required
Unison Industries
ATTN: Debbie Reid
7575 Baymeadows Way
Jacksonville, FL 32256
Ignition System Reliability
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5
Potential Improvement Areas for Ignition System Dispatch Reliability
• A/C Start Brake Assembly - Significant Improvement
- Refer to Boeing Service Letter 737-SL-76-020 and Maintenance Tip
737MT73-001
• A/C Automatic Ignition Transfer Relay Option
- Boeing offers an option that allows dispatch with an inoperative right ignition
system but does not require opening the fan cowls
• Contact your Boeing Customer Engineering representative for
production cost and availability information
• Contact Boeing Airplane Services for retrofit cost and availability
information at airplaneservices@boeing.com
- Reduce D&Cs 30+ percent
Ignition System Reliability
February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6
CFM56-7B Fleet - Engine Cycles
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50
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350
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50
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350
Number of Engines
ECSN Distribution

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CFM Ignition System Reliability