Narrative:

During cruise flight at FL360 got alert 'tank 3 tip lo' for fuel tank 3 about 45 minutes into flight. We checked the QRH for this level 1 alert and the fuel system corrected the problem without any manual intervention. This condition is not unusual and normally corrects itself; but this contributed to our suspicion of the accuracy of the fuel system later. About 10 minutes later we got level 2 alert 'fuel qty/used check'. We ran the QRH checklist and noted that this could be a possible fuel leak. We were concerned that the previous mentioned tip lo condition may have vented fuel overboard. We calculated our fob from the fuel used gauges and tank quantity including the known start fuel in the blocks of 65.0. We determined that we were 5.0 short on indicated fuel which did not make sense given that we were 20k light on payload. Per the QRH we selected the fuel system to manual and monitored the fuel closely for the next 40 minutes. We determined that the fuel leak did not increase but we were 5k unaccounted for and were concerned that it was either overboard or in the aircraft belly. The FMS was predicting us getting to ZZZ with 17.5 fob. We noted that all fuel gauges were fluctuating +/- 1000 but number 2 was +/- 2000 pounds. We agreed and elected to make a precautionary diversion in order to land with sufficient fuel and have maintenance fix the problem. We kept dispatch and mx in the loop with numerous ACARS messages.we did not want to fly over terrain at night with suspect fuel indications. We also did not declare an emergency with ATC but did a precautionary divert. We did an autoland with no further problems. After consulting with maintenance they said we in fact had a tank 2 fuel indicator fault. After a few hours we uploaded more fuel; they MEL'd the number 2 fuel tank quantity indicator inop; refueled the airplane to a known sticked fuel of 50.0 and continued on with no further problems.

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Original NASA ASRS Text

Title: MD-11 flight crew reported fuel quantity anomalies while in cruise. The flight diverted and landed normally.

Narrative: During cruise flight at FL360 got alert 'TANK 3 Tip LO' for fuel tank 3 about 45 minutes into flight. We checked the QRH for this level 1 alert and the fuel system corrected the problem without any manual intervention. This condition is not unusual and normally corrects itself; but this contributed to our suspicion of the accuracy of the Fuel System later. About 10 minutes later we got Level 2 Alert 'FUEL QTY/USED CHK'. We ran the QRH checklist and noted that this could be a possible fuel leak. We were concerned that the previous mentioned TIP LO condition may have vented fuel overboard. We calculated our FOB from the fuel used gauges and tank quantity including the known start fuel in the blocks of 65.0. We determined that we were 5.0 short on indicated fuel which did not make sense given that we were 20k light on payload. Per the QRH we selected the fuel system to manual and monitored the fuel closely for the next 40 minutes. We determined that the fuel leak did not increase but we were 5k unaccounted for and were concerned that it was either overboard or in the aircraft belly. The FMS was predicting us getting to ZZZ with 17.5 FOB. We noted that all fuel gauges were fluctuating +/- 1000 but number 2 was +/- 2000 pounds. We agreed and elected to make a precautionary diversion in order to land with sufficient fuel and have maintenance fix the problem. We kept Dispatch and MX in the loop with numerous ACARS messages.We did not want to fly over terrain at night with suspect fuel indications. We also did not declare an emergency with ATC but did a precautionary divert. We did an autoland with no further problems. After consulting with Maintenance they said we in fact had a tank 2 fuel indicator fault. After a few hours we uploaded more fuel; they MEL'd the number 2 fuel tank quantity indicator inop; refueled the airplane to a known sticked fuel of 50.0 and continued on with no further problems.

Data retrieved from NASA's ASRS site 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.