Service difficulty report · O-Ring · Boeing 747422

Difficulty date
September 25, 2007
Submitted
October 23, 2007
Operation
Air carrier
Aircraft
N196UA
Make and model
Boeing 747422
Aircraft serial
28715
Aircraft time
42,099 hours, 5,182 cycles
Engine
Pwa PW4056
Part
O-Ring
Condition
Leaking
Location
Nr 2 Fuel Tank
Stage of operation
NR
How discovered
9
Nature of condition
K
Precautionary procedure
O

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

What was found

UNWANTED FUEL TRANSFER. NR 2 MAIN TO CENTER 100LBS EVERY 4+ MINUTES. *S/D* FOUND COUPLINGS ON THE SCAVENGE SYSTEM LEAKING IN THIRD BAY, LEFT SIDE, AT THE BOTTOM. REPLACED O-RINGS. OPS CHECK AND LEAK CHECK GOOD. SUSPECT VIBRATION & MULTIPLE USE CYCLES LED TO O-RING DETERIORATION.