Service difficulty report · Valve · Boeing 747422

Difficulty date
August 25, 2010
Submitted
September 17, 2010
Operation
Air carrier
Aircraft
N173UA
Make and model
Boeing 747422
Aircraft serial
24380
Aircraft time
79,547 hours, 9,040 cycles
Engine
Pwa PW4056
Part
Valve
Part number
40885
Condition
Faulty
Location
Fuel System
Stage of operation
IN
How discovered
9
Nature of condition
O
Precautionary procedure
K

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

What was found

PRESSURE CHECKED SYS AND FOUND FUEL GOING INTO 2R AND 2M WITH ALL VALVES CLOSED, SUSPECT FUEL GOING INTO 2R AND UNWANTED FUEL TRANSFERRING INTO 2M. REPLACED NR 2 RESERVE FUELING VALVE. OP CHECKED NR 2 RESERVE TANK STILL TAKING FUEL. REMOVED FUEL PANEL 545BB FOR ACCESS LT WING. FOUND #2 RES AND #2 MAIN OTBD FUELING VALVES BAD. CAUSING TANKS TO OVER FILL.NO NEED TO V TO ENTIRE AIRCRAFT NO PAST HISTORY OF THAT SYS FAILING. DID ACP VTO CK ON NR 2 MAIN AND 2 & 3 RES. SYS WORKS NORMAL AND PRESS CHK OF FUELING MANIFOLD. NO UNWANTED FUELING NOTED.