Service difficulty report · Fuel Tank · Boeing 747422

Difficulty date
October 3, 2010
Submitted
November 1, 2010
Operation
Air carrier
Aircraft
N173UA
Make and model
Boeing 747422
Aircraft serial
24380
Aircraft time
80,017 hours, 9,090 cycles
Engine
Pwa PW4056
Part
Fuel Tank
Condition
Leaking
Location
Fuel System
Stage of operation
IN
How discovered
V
Nature of condition
K
Precautionary procedure
K

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

What was found

RAMP REPORTED FUEL COMING OUT OF FWD SMALL HOLE ON APU DRAIN MASK. WHILE IN STAB COMPARTMENT, OBSERVED RUNNING FUEL LEAK (ALMOST A STEADY STREAM) FROM THE AFT LT CORNER OF CTR SECTION OF STABILIZER TANK. FUEL IS EXITING ACFT FROM FUSELAGE DRAINS AND DRAIN HOLE IN DRAIN MAST - NOT THE DRAIN MAST DRAIN LINES OF THE MAST. FUEL LEAK COMING FROM AFT SIDE OF THE CENTER SECTION OF HORIZONTAL STAB FUEL TANK, TANK INOPERATIVE EMPTY. ALL 4 ISOLATION VALVES INOP. RECONNECTED 2EA AFT HST FUEL ISOLATION VALVES AND 2EA FUEL ISOLATION VALVES IN WHEEL WELL FOR LEAK CHECK. ACCOMPLISHED AFT HST LEAK CHECK AFTER COMPLETED REPAIRS ON ALL AFFECTED AREAS. NO LEAKS FOUND.