Service difficulty report · Circuit Card · Boeing 767322

Difficulty date
December 29, 2009
Submitted
December 30, 2009
Operation
Air carrier
Aircraft
N668UA
Make and model
Boeing 767322
Aircraft serial
30024
Aircraft time
38,750 hours, 10,515 cycles
Engine
Pwa PW4056
Part
Circuit Card
Part number
285T00946
Part serial
3062
Condition
Malfunctioned
Location
A/C Pack Control
Stage of operation
NR
How discovered
9
Nature of condition
J
Precautionary procedure
O

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

What was found

ALL 4 PACK CONTROLLERS FLUCTUATING IN AUTO, A PREVIOUS AUTO EVENT SHOWED PACK OUT TEMP LEF +21 AND RT -2. SUSPECT THE RAM AIR SYS ON THE RT SIDE IS OFF SCHEDULE WITH THE PACK TEMP CONTROLLER. THE TEMP CONTROLLER CARD ON THE RT SIDE MAY BE AT FAULT. (LT PREVIOUSLY REPLACED.) POSSIBLE TEMP CONTROL VALVE NOT OPERATING PROPERLY. REPLACED TEMP CONTROLLER CARD ASSY RT M10404, CHECKS OK. CHECKED SENSE LINES AND FOUND LINE AT LOW LIMIT VALVE PACK OUTLET PORT VERY LOOSE. SECURED LINE. LEAK AND OP CKS OK. ALSO RPL'D TRIM AIR PRESSURE AIR REGULATING VALVE DUE TO STICKING.