Narrative:

The flight began with MEL 28-22-01-01-a fuel tank 1 aft pump inop with direction to run the fsc in auto and to add 2;000 pounds of fuel as MEL penalty. On climbout; received a level 1 alert main tank pumps off and observed on the synoptic; tank 1 pumps off; transfer pump on and crossfeed open. Cycled the fsc from auto to manual to auto and the system fixed itself; returning to tank to engine operation. Later in flight; at cruise; received a level 1 alert engine 1 suct feed and observed on the synoptic; all pumps off and crossfeed closed. Put fsc in manual and the system returned to tank to engine operation; decided to continue flight in manual; suspecting trouble with the fsc. At FL370; approaching ZZZ; received a level 1 alert tnk 3 tip trapped (5;800 pounds unusable) and shortly thereafter another alert tnk 3 fuel qty lo. Taking into account the fuel status and the distance/time/fuel burn remaining to destination; the decision was made that landing at the nearest suitable airport was the safest course of action. ZZZ was the nearest suitable airport. An emergency was declared to ensure priority handling and the descent; approach and landing was uneventful. This was a fuel problem that developed as a result of a fuel MEL and multiple fuel system malfunctions. Adding additional fuel in anticipation of multiple fuel malfunctions is an alternative; but operationally; probably not cost effective.

Related reports:

Google
 

Original NASA ASRS Text

Title: Air Carrier flight crew reports departing with a deferral for Fuel Tank 1 Aft Pump Inoperative with direction to run the FSC in Auto and to add 2;000 LBS of fuel as MEL Penalty. During the next two and one half hours of flight multiple valve and pump anomalies are observed and corrected by placing the FSC to manual then back to auto; then finally leaving it in manual. When an alert is received for trapped fuel in number three tip tank the crew elects to divert.

Narrative: The flight began with MEL 28-22-01-01-A Fuel Tank 1 Aft Pump Inop with direction to run the FSC in Auto and to add 2;000 LBS of fuel as MEL penalty. On climbout; received a Level 1 alert MAIN TANK PUMPS OFF and observed on the synoptic; tank 1 pumps off; transfer pump on and crossfeed open. Cycled the FSC from Auto to Manual to Auto and the system fixed itself; returning to tank to engine operation. Later in flight; at cruise; received a Level 1 alert ENG 1 SUCT FEED and observed on the synoptic; all pumps off and crossfeed closed. Put FSC in Manual and the system returned to tank to engine operation; decided to continue flight in Manual; suspecting trouble with the FSC. At FL370; approaching ZZZ; received a Level 1 alert TNK 3 TIP TRAPPED (5;800 LBS unusable) and shortly thereafter another alert TNK 3 FUEL QTY LO. Taking into account the fuel status and the distance/time/fuel burn remaining to destination; the decision was made that landing at the nearest suitable airport was the safest course of action. ZZZ was the nearest suitable airport. An emergency was declared to ensure priority handling and the descent; approach and landing was uneventful. This was a fuel problem that developed as a result of a Fuel MEL and multiple fuel system malfunctions. Adding additional fuel in anticipation of multiple fuel malfunctions is an alternative; but operationally; probably not cost effective.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.