Service difficulty report · Pump · Boeing 747422

Difficulty date
November 23, 1998
Submitted
March 26, 2000
Operation
Air carrier
Aircraft
N107UA
Make and model
Boeing 747422
Aircraft serial
26900
Engine
Pwa PW4056
Part
Pump
Part number
6072101
Condition
Damaged
Location
Nr 2
Part time
644 hours
Component
Cranehydroai · 6072101
Stage of operation
NR
Nature of condition
J
Precautionary procedure
K

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

What was found

FUEL OVERRIDE/JETTISON PUMP PART NR 60-72101 DASH 2 RECOVERED FROM THE NR 2 MAIN FUEL TANK (FWD POSITION) OF ACFT 8407 WAS FOUND TO EXHIBIT EXCESSIVE IMPELLER END-PLAY AND GOUGING OF THE IMPELLER UNIT WITH THE INLET ADAPTER. TESTING OF THE PUMP BY THE VENDOR SHOWED THAT THE AXIAL THRUST-BALANCING MECHANISM FAILED. THE THRUST WASHER/BEARING IS SUSPECTED TO HAVE BEEN MANUFACTURED INCORRECTLY. ROOT CAUSE OF FAILURE HAS NOT BEEN IDENTIFIED AS YET.