CFM OIL TEMPERATURE SENSOR DISENGAGEMENT

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CFM OIL TEMPERATURE SENSOR DISENGAGEMENT

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December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1
OIL TEMPERATURE SENSOR
DISENGAGEMENT
• EVENT NARRATIVE
• HARDWARE INVESTIGATION
• CORRECTIVE ACTION PLAN
December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2
• EVENT NARRATIVE
– 12 minutes into flight during climb, Eng #2 oil quantity decreased rapidly
to zero
– LOW OIL PRESS light illuminated about 3 minutes later
– Pilot reported 'big abnormal noise' like something 'broken' from the
engine and oil fume in cabin.
– Crew shut down the engine.
– Ground inspection showed oil temperature sensor disengaged from the
sensor probe housing.
• all the oil expelled from the engine
Oil Temp. Sensor Disengagement
December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3
• HARDWARE INVESTIGATION
– Oil Temp. Sensor with attachment bolts and self locking inserts
disengaged all together.
– All components, probe, bolts and housing checked and meet blue print.
– No interference marks found between bolts end and housing holes.
– Holes threads in Housing found sheared.
– Grease found on bolts instead of Engine Oil per spec.
– Oil Temp. Sensor disengaged due to inserts becoming loose in housing
caused by overtorque applied on attachment bolts.
Oil Temp. Sensor Disengagement
December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4
• DELAYED WARNING INVESTIGATION
– Oil Pressure signal dropped out of valid range
(PEO = Poil - P25 < -2.03 Psid)
• Oil Pressure not provided to DEU anymore by the EEC.
• No valid Oil Pressure -> No Low Oil Pressure Warning.
– Oil Pressure came back valid when throttle retarded (P25 droop)
(PEO > -2.03 Psid)
• Low Oil Pressure Warning came ON.
Oil Temp. Sensor Disengagement
December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5
Oil Temp. Sensor location
Housing
Oil Temp. Sensor
Oil Temp. Sensor Disengagement
December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6
Oil Temp. Sensor Disengagement
Inserts
Bolt
Oil Temp
Sensor
Probe
Insert with
housing
thread
December 2000 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 7
• CORRECTIVE ACTION PLAN
– OIL TEMP SENSOR MOUNTING
• New housing with current inserts (649-067-001-0) replaced by longer inserts
(649-773-170-0).
– Bolt will brake if overtorque applied (verified through testing).
– Same bolts used with this new insert.
– Torque value to remain the same (4.2 to 4.7 N.m) in order to avoid
mixing in fleet.
• Production introduction point: 1st quarter 2001.
• Caution to be added in production assembly line and AMM.
– LOW OIL PRESS WARNING
• PEO Selection logic change defined.
• To be introduced at next 7BM EEC Software.
– expected release date: Apr. 2001
Oil Temp. Sensor Disengagement