SDR UALA2010100403643

Service difficulty report · Check Valve · Boeing 777222

Difficulty date: October 2, 2010
Submitted: October 29, 2010
Operation: Air carrier
Aircraft: N777UA
Make and model: Boeing 777222
Aircraft serial: 26916
Aircraft time: 62,536 hours, 11,580 cycles
Engine: Pwa PW4077
System (JASC): 2820 · Aircraft Fuel Distribution System
Part: Check Valve
Condition: Faulty
Location: Fuel System
Stage of operation: CR
How discovered: O
Nature of condition: J
Precautionary procedure: O

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

What was found

FUEL IMBALANCE MSG 55 MIN AFT TAKEOFF RT MAIN TANK INCREASING 100 LBS EVERY 5 MIN WITH CTR TANK PUMPS ON. LT MAIN QUANTITY NORMAL AND STEADY. WITH RT CTR TANK PUMP OFF RT WING QTY STOPS INCREASING & IMBALANCE STOPS. REPLACED RT FWD AND RT AFT BOOST PUMP DISCHARGE CK VALVE. RAN ALL BOOST PUMPS IN LT AND RT MAIN TANKS AND CTR TANK PUMPS WITH CROSSFEED VALVES OPEN. NO FUEL TRANSFER OBSERVED. THEN RAN BOTH ENGS WITH ALL PUMPS ON & CROSSFEEDS OPEN FOR 25 MINS AND HAD NO FUEL TRANSFER.