CFM T12 Sensor Failure

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CFM T12 Sensor Failure

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CFM T12 Sensor Failure

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T12 Sensor
Failure
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 2
History
• Several T12 failures experienced since EIS
- Operational impact: thrust fluctuation
- Internal wire rupture
- Both sources affected
- P/N 0154GL5 (Rosemount)
- P/N RP198-00 (Auxitrol).
- Connector welding bead rupture
- P/N RP198-00 only
• Improved T12 sensors released
- SB 73-080, Rosemount source, cat 7, June 00
- P/N 0154GL5 for S/N YA043001 and up.
- SB 73-085, Auxitrol source, cat 6, Feb. 01
- P/N RP198-01
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 3
Background
• 4 post SB 73-085 T12 sensor failures
- P/N RP198-01 only (Auxitrol)
- 2 air turn backs due to N1 fluctuations
- Connectors separated from sensor body
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 4
Investigations
• Connectors ruptured at weld bead location
- Insufficient weld bead depth, does not conform to
specification
• Connector welding process audit
- TIG welding process performed
- Welding machine parameters caused variation in weld
bead depth
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 5
0.4/0.48mm (0.6mm mini specified)
Sensor Body
Weld bead
Connector
Connector Welding
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 6
Investigations - Conclusions
• Entire RP198-01 production suspected
- 304 sensors
- S/N YC135800 to YC136096
- S/N YC136115 to YC136119
- S/N YC136133 and 136134
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 7
• At Vendor’s production level
- TIG welding process improvements validated Jan. 02
- Welding jig refined to ensure repeatability
- Setting parameters modified
- Rework qualified on T12 sensor assembly Jan. 02
- Re-welding of connector
- Improved production jig and welding parameters
used
Corrective Actions
CFM56 Operators Conference – May 21 - 22, 2001 CFM Proprietary Data Unauthorized Disclosure Prohibited 8
• Field plan
- Retrofit of RP198-01 sensors
- Repair applied to returned parts
- Specific part identification
- SB targeted end April 02
Corrective Actions