Narrative:

After a normal start, taxi, takeoff and climb, I noticed what appeared to be a fuel quantity gauge problem in the #2 tank of an large transport. After informing the captain of the possible problem, we tested the indicator and it appeared to test good. At that point captain told me to get the manual out for fuel quantity decreasing procedures, and I worked with the first officer about finding a close place to land. I noticed this suspected problem at approximately 20 mins into the flight. The #2 tank gauge appeared to be steadily decreasing and indicating approximately 3000-4000#. We had left nashville, tn with 21000 pounds total in the fuel tanks; #1, 2 and 3 = 7000 pounds each. Our final destination was raleigh-durham airport. After getting out the manual, I ensured the xfeeds were open, because the #2 tank was decreasing at such a rate that I did not want the #2 engine to flame out prior to reviewing the checklist. With the checklist out, I conferred with the captain and we decided, based on our indications, that we did have a fuel leak somewhere and the #2 tank was losing the fastest. At this point in time, we were probably down to 3000# in the center tank. The next item in our checklist tells us to go to tank to engine feed, record the fuel quantities and send a crew member back to inspect for possible wing fuel steadily decreasing. We also did not go tank to engine at the time because the first officer made a comment about a possible flame-out on #2 engine if we went tank to engine at such a low fuel state with the fuel decreasing. At the time this made good sense, so we continued on with the checklist (while off course deciding where to go, how to get there and talking with ATC). The next checklist step then tells us to go tank to engine feed and determine which tank/engine combination had the faster fuel decrease rate. We knew already this to be engine #2, so we went tank to engine and noted what appeared to be no decrease in the fuel decrease rate. With this, we continued with the engine shutdown procedure as per the checklist. There appeared to be, as a guess, maybe 1000 pounds left in tank #2 after shutdown. This time span from discovery of a perceived problem and then engine shutdown was approximately 10 mins, leaving approximately 20 mi mins for the approach and final landing into atl. Fuel upon landing indicated: #1 = 6000 pounds, #2 = 200-300 pounds, and #3 = 5600 pounds. Conclusions: our #1 concern was the safety of our passenger. We all perceived a fuel leak from #2 tank. Because maintenance could not duplicate the problem or find a leak or faulty gauge, there is the possibility of a crew-induced problem. If all xfeeds are left open on an large transport, fuel will tend to be fed from #2 engine with some variances in pump pressures. I'm not totally convinced that was the problem, but fatigue was a factor. It was our fourth leg of a catch-up day at night. We already had diverted once for a short, wet runway--we were too heavy. We all perceived and saw the same problem. The checklist led us to believe it was indeed a leak. Given all the circumstances at the time, we made a judgement decision based on the side of safety. The passenger were very appreciative and no one was hurt or distraught.

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Original NASA ASRS Text

Title: ACR LGT FLT CREW PERCEIVED A FUEL LEAK AND DECIDED TO RETURN TO ATL, ONLY TO FIND OUT IT WAS FLT CREW-INDUCED BY POOR FUEL MANAGEMENT.

Narrative: AFTER A NORMAL START, TAXI, TKOF AND CLB, I NOTICED WHAT APPEARED TO BE A FUEL QUANTITY GAUGE PROB IN THE #2 TANK OF AN LGT. AFTER INFORMING THE CAPT OF THE POSSIBLE PROB, WE TESTED THE INDICATOR AND IT APPEARED TO TEST GOOD. AT THAT POINT CAPT TOLD ME TO GET THE MANUAL OUT FOR FUEL QUANTITY DECREASING PROCS, AND I WORKED WITH THE F/O ABOUT FINDING A CLOSE PLACE TO LAND. I NOTICED THIS SUSPECTED PROB AT APPROX 20 MINS INTO THE FLT. THE #2 TANK GAUGE APPEARED TO BE STEADILY DECREASING AND INDICATING APPROX 3000-4000#. WE HAD LEFT NASHVILLE, TN WITH 21000 LBS TOTAL IN THE FUEL TANKS; #1, 2 AND 3 = 7000 LBS EACH. OUR FINAL DEST WAS RALEIGH-DURHAM ARPT. AFTER GETTING OUT THE MANUAL, I ENSURED THE XFEEDS WERE OPEN, BECAUSE THE #2 TANK WAS DECREASING AT SUCH A RATE THAT I DID NOT WANT THE #2 ENG TO FLAME OUT PRIOR TO REVIEWING THE CHKLIST. WITH THE CHKLIST OUT, I CONFERRED WITH THE CAPT AND WE DECIDED, BASED ON OUR INDICATIONS, THAT WE DID HAVE A FUEL LEAK SOMEWHERE AND THE #2 TANK WAS LOSING THE FASTEST. AT THIS POINT IN TIME, WE WERE PROBABLY DOWN TO 3000# IN THE CENTER TANK. THE NEXT ITEM IN OUR CHKLIST TELLS US TO GO TO TANK TO ENG FEED, RECORD THE FUEL QUANTITIES AND SEND A CREW MEMBER BACK TO INSPECT FOR POSSIBLE WING FUEL STEADILY DECREASING. WE ALSO DID NOT GO TANK TO ENG AT THE TIME BECAUSE THE F/O MADE A COMMENT ABOUT A POSSIBLE FLAME-OUT ON #2 ENG IF WE WENT TANK TO ENG AT SUCH A LOW FUEL STATE WITH THE FUEL DECREASING. AT THE TIME THIS MADE GOOD SENSE, SO WE CONTINUED ON WITH THE CHKLIST (WHILE OFF COURSE DECIDING WHERE TO GO, HOW TO GET THERE AND TALKING WITH ATC). THE NEXT CHKLIST STEP THEN TELLS US TO GO TANK TO ENG FEED AND DETERMINE WHICH TANK/ENG COMBINATION HAD THE FASTER FUEL DECREASE RATE. WE KNEW ALREADY THIS TO BE ENG #2, SO WE WENT TANK TO ENG AND NOTED WHAT APPEARED TO BE NO DECREASE IN THE FUEL DECREASE RATE. WITH THIS, WE CONTINUED WITH THE ENG SHUTDOWN PROC AS PER THE CHKLIST. THERE APPEARED TO BE, AS A GUESS, MAYBE 1000 LBS LEFT IN TANK #2 AFTER SHUTDOWN. THIS TIME SPAN FROM DISCOVERY OF A PERCEIVED PROB AND THEN ENG SHUTDOWN WAS APPROX 10 MINS, LEAVING APPROX 20 MI MINS FOR THE APCH AND FINAL LNDG INTO ATL. FUEL UPON LNDG INDICATED: #1 = 6000 LBS, #2 = 200-300 LBS, AND #3 = 5600 LBS. CONCLUSIONS: OUR #1 CONCERN WAS THE SAFETY OF OUR PAX. WE ALL PERCEIVED A FUEL LEAK FROM #2 TANK. BECAUSE MAINT COULD NOT DUPLICATE THE PROB OR FIND A LEAK OR FAULTY GAUGE, THERE IS THE POSSIBILITY OF A CREW-INDUCED PROB. IF ALL XFEEDS ARE LEFT OPEN ON AN LGT, FUEL WILL TEND TO BE FED FROM #2 ENG WITH SOME VARIANCES IN PUMP PRESSURES. I'M NOT TOTALLY CONVINCED THAT WAS THE PROB, BUT FATIGUE WAS A FACTOR. IT WAS OUR FOURTH LEG OF A CATCH-UP DAY AT NIGHT. WE ALREADY HAD DIVERTED ONCE FOR A SHORT, WET RWY--WE WERE TOO HEAVY. WE ALL PERCEIVED AND SAW THE SAME PROB. THE CHKLIST LED US TO BELIEVE IT WAS INDEED A LEAK. GIVEN ALL THE CIRCUMSTANCES AT THE TIME, WE MADE A JUDGEMENT DECISION BASED ON THE SIDE OF SAFETY. THE PAX WERE VERY APPRECIATIVE AND NO ONE WAS HURT OR DISTRAUGHT.

Data retrieved from NASA's ASRS site as of July 2007 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.