Service difficulty report · Sensor · Boeing 767322

Difficulty date
March 10, 2000
Submitted
October 4, 2000
Operation
Air carrier
Aircraft
N673UA
Make and model
Boeing 767322
Aircraft serial
29241
Aircraft time
440 hours, 160 cycles
Engine
Pwa PW4052
Part
Sensor
Condition
Out Of Tolerance
Location
A/C Pack
Stage of operation
CL
How discovered
O
Nature of condition
N
Precautionary procedure
H, A

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

LT PACK OFF AND TEMP MESSAGE DISPLAYED ON EICAS, SAME AFTER RESET. ODOR IN CABIN WHEN OPERATING IN STBY NORMAL. PACK SELECTED TO OFF. RETURNED TO LAX. *S/D* LT PACK OFF AND TEMP MESSAGE WAS PROBABLY CAUSED BY A COMPRESSOR OUTLET SENSOR THAT WAS NOT PROPERLY CALIBRATED AND A RAM AIR EXIT DOOR ACTUATOR THAT WOULD NOT OPEN. FAULTS ALLOWED THE COMPRESSOR TO REACH 490 DEG F, CAUSING THE COMPRESSOR OVERHEAT SWITCH TO CLOSE. THE PACK INOP AND OFF LIGHTS WERE ILLUMINATED. THE COMPRESSOR OVERHEAT SWITCH WAS REPLACED WITHOUT FIXING THE FAULT. A SECOND RAM AIR EXIT ACTUATOR WAS INSTALLED TO CLEAR THE PACK BITE MESSAGE. THE SHOP FINDINGS FOR BOTH RAM AIR EXIT ACTUATORS REMOVED FROM 6773.