Service difficulty report · Unknown · Boeing 747422

Difficulty date
September 7, 2011
Submitted
September 9, 2011
Operation
Air carrier
Aircraft
N128UA
Make and model
Boeing 747422
Aircraft serial
30023
Aircraft time
46,069 hours, 5,488 cycles
Engine
Pwa PW4056
Part
Unknown
Condition
Malfunctioned
Location
Fuel System
Stage of operation
IN
How discovered
O
Nature of condition
O
Precautionary procedure
O

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

What was found

TANK TO ENG 1000LBS IMBALANCE NUMBER 3 GREATER THAN 2 TANK. PERFORMED MANIFOLD PRESS CK WITH ALL PUMPS ON. FUEL LEAKS INTO TNKS NR 2 AND 3 AT THE RATE OF 500LB TO 600LB EVERY 30 MIN. PRESSURE CKD USING FUEL TANKER. NO FUEL TRANSFER OBSERVED. PERFORMED FUEL SYSTEM SCAVENGE CHECK LOW LEVEL AND HIGH LEVEL CHECK. SYSTEM CHECKED GOOD. WITH 2M & 3M AT 65K EA RAN CENTR TK OJ PUMPS FOR 40 MINS WITH NO MOVEMENT NOTED. THEN WE TOP OFF 1M AND 4M, ALSO 2R & 3R. NO MOVEMENT FOR 90 MINS. THEN WITH 4M TOP OFF, WE OPENED 645BB AND LOOKED AT WALL BETWEEN 3 & 4M WITH NO LEAK NOTED. REMOVED 645BB FOR ACCESS. INSTALLED 645BB. NEEDS LEAK CHECK. ACP'D HI LEVEL AND LO LEVEL SCAVENGE SYS TEST.