Service difficulty report · Pump

Difficulty date
March 4, 2008
Submitted
March 5, 2008
Operation
General aviation
Part
Pump
Part number
38809981
Condition
Failed
Location
Apu Oil
Part time
13,599 hours, 1,468 cycles
Stage of operation
NR
How discovered
O
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

2 APUS WERE REPORTED LOP AUTO SHUTDOWN. HAVE RECEIVED APU P-195 AND P-141 FROM FOR THE SAME REASON OF REMOVAL. DISASSEMBLY OF THE ENGINES REVEALED LP ROLLER BEARING FAILURE. ONE OF THE ENGINE'S BEARING DID NOT HAVE LUBRICATION AT ALL. THE OIL PUMPS P/N 3880998-1 WERE ROUTED TO BENCH TEST AND LOW PERFORMANCE WAS NOTED. DISASSEMBLY OF THE OIL PUMP REVEALED PORT PLATE P/N 3603681-1 HAD SIGNIFICANTLY WORN. IT ALLOWED THE PORT PLATE MOVE TO RESTRICT THE OIL INLET PORT AND OUTLET PORT AND CAUSED LOW PUMP PERFORMANCE. THE BEARING FAILURE WAS A CONSEQUENCE OF INSUFFICIENT OIL PRESSURE.