Narrative:

Cruise mach was .87 at FL330. I first saw the autothrottles retard to idle and suspected an overspd protection event. I reselected M.84. Then a level 1 alert of 'tank 2 qty lo' came on. I selected the fuel page to see #1 tank reading 600 pounds; #2 0 pounds; #3 600 pounds; and tail tank had 6800 pounds. 10 minutes prior; the fuel check was 46K. There was no other annunciations; malfunctions; or 'X's on the fuel gauges. It appeared we had developed a massive fuel leak. None of our checklists addressed this particular situation and it appeared we had a massive fuel leak in the system. ZZZZ airport was about 80 miles away and I advised ATC that we had a problem and needed to head towards ZZZZ as soon as possible. I got the relief pilot to begin the checklist with the assistance of a jumpseater as myself and the first officer worked on getting us down on the ground before we ran out of fuel. None of our checklists addressed our situation and under my direction the relief pilot found and pulled the quantity power circuit breaker's as we were overhead ZZZZ. At that point we had 3800 pounds of fuel. There were no lights on at the airport as ATC was trying to get someone on ZZZZ airport to turn on the ILS and runway lights. At that time it appeared that the tail tank was supplying the fuel to all of the engines and we were moments from an all engine flameout due to fuel starvation. Upon resetting the circuit breaker's; we recovered the fuel gauges but could not verify accurate quantities or normal operations of the fuel system. We had selected the other systems controller; went into manual and tested the gauges; with no resolution prior to pulling and resetting the quantity circuit breaker's. There is a note in the QRH suggesting if an extra crew member was available to try this procedure. Upon landing in ZZZZ1; maintenance boarded the aircraft and performed a systems test. No faults were noted or shown on the cfds; however the FMC's had gone into 'timeout' twice and it was 'suggested' by maintenance that the FMC's were the cause of the problem; as per the logbook. The aircraft's fuel quantity was not verified by the sticks and the aircraft was cleared for continued service; across the ocean with no corrective action taken and no cause for the glitch identified or found. During the discussions with maintenance control and the mechanics on duty we ran out of duty time to continue on to destination. (We were already 2 hours late from a mechanical and had a 14+30 duty day prior to any problems.) a problem of this magnitude needs to be addressed and corrective action taken to identify and fix the problem. Given the information we had; we could have been forced into a situation of making an emergency landing at night at a strange airport with no lights on the runway or ditch in the ocean. I must commend my crew for teamwork and professionalism displayed during an 'unheard of emergency situation.'callback conversation with reporter revealed the following information: reporter stated in his communication with other pilots resulted in reports of two nearly identical instances on separate aircraft in the fleet. One happened on final to the planned destination but the second was similar to the reporter's incident with fuel dropping almost to zero from a perfectly normal reading at the previous reporting point. Again; a fear of a massive fuel leak drove the decision making. In this case the flight diverted for an emergency landing. Through their own investigation; the reporter; a training check airman on the fleet; learned maintenance subsequently replaced a unit referred to only as an 'electrical system module' which contained allegedly faulty software. The reporter was uncertain as to the effect it has on the problem or even if the reason for the replacement was a direct consequence. The reporter is concerned the air carrier has made no attempt to date to inform the flight crews of the potential for this problem and to specify a special procedure for addressing it (the pulling and resetting of the circuit breakers) in a rapid and specific manner. The reporter reiterated the seriousness of the course of action on which they were originally committed; ie; landing at a dark; closed airport without benefit of any electronic guidance in order to avoid a possible all engine flameout due to fuel starvation. Finally; the common element of these events appears to be a dramatic drop in fuel quantity from a massive fuel leak but; upon examination; subsequent fuel burn from that point appeared consistent with normal fuel flow.

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Original NASA ASRS Text

Title: AN MD11 FLT CREW DECLARES AN EMER WHEN FUEL QUANTITY SUDDENLY DROPS FROM 46K TO LESS THAN 10K WITH DEST STILL SEVERAL HUNDRED MILES AHEAD. CREW IS ULTIMATELY ABLE TO RESOLVE INACCURATE FUEL QUANTITY INDICATIONS BEFORE ACTUALLY MAKING AN EMER LNDG AT A CLOSED AND UNLIGHTED ARPT.

Narrative: CRUISE MACH WAS .87 AT FL330. I FIRST SAW THE AUTOTHROTTLES RETARD TO IDLE AND SUSPECTED AN OVERSPD PROTECTION EVENT. I RESELECTED M.84. THEN A LEVEL 1 ALERT OF 'TANK 2 QTY LO' CAME ON. I SELECTED THE FUEL PAGE TO SEE #1 TANK READING 600 LBS; #2 0 LBS; #3 600 LBS; AND TAIL TANK HAD 6800 LBS. 10 MINUTES PRIOR; THE FUEL CHK WAS 46K. THERE WAS NO OTHER ANNUNCIATIONS; MALFUNCTIONS; OR 'X'S ON THE FUEL GAUGES. IT APPEARED WE HAD DEVELOPED A MASSIVE FUEL LEAK. NONE OF OUR CHKLISTS ADDRESSED THIS PARTICULAR SITUATION AND IT APPEARED WE HAD A MASSIVE FUEL LEAK IN THE SYSTEM. ZZZZ ARPT WAS ABOUT 80 MILES AWAY AND I ADVISED ATC THAT WE HAD A PROBLEM AND NEEDED TO HEAD TOWARDS ZZZZ ASAP. I GOT THE RELIEF PLT TO BEGIN THE CHKLIST WITH THE ASSISTANCE OF A JUMPSEATER AS MYSELF AND THE FO WORKED ON GETTING US DOWN ON THE GND BEFORE WE RAN OUT OF FUEL. NONE OF OUR CHKLISTS ADDRESSED OUR SITUATION AND UNDER MY DIRECTION THE RELIEF PLT FOUND AND PULLED THE QUANTITY POWER CB'S AS WE WERE OVERHEAD ZZZZ. AT THAT POINT WE HAD 3800 LBS OF FUEL. THERE WERE NO LIGHTS ON AT THE ARPT AS ATC WAS TRYING TO GET SOMEONE ON ZZZZ ARPT TO TURN ON THE ILS AND RWY LIGHTS. AT THAT TIME IT APPEARED THAT THE TAIL TANK WAS SUPPLYING THE FUEL TO ALL OF THE ENGS AND WE WERE MOMENTS FROM AN ALL ENG FLAMEOUT DUE TO FUEL STARVATION. UPON RESETTING THE CB'S; WE RECOVERED THE FUEL GAUGES BUT COULD NOT VERIFY ACCURATE QUANTITIES OR NORMAL OPERATIONS OF THE FUEL SYSTEM. WE HAD SELECTED THE OTHER SYSTEMS CTLR; WENT INTO MANUAL AND TESTED THE GAUGES; WITH NO RESOLUTION PRIOR TO PULLING AND RESETTING THE QUANTITY CB'S. THERE IS A NOTE IN THE QRH SUGGESTING IF AN EXTRA CREW MEMBER WAS AVAILABLE TO TRY THIS PROC. UPON LNDG IN ZZZZ1; MAINT BOARDED THE ACFT AND PERFORMED A SYSTEMS TEST. NO FAULTS WERE NOTED OR SHOWN ON THE CFDS; HOWEVER THE FMC'S HAD GONE INTO 'TIMEOUT' TWICE AND IT WAS 'SUGGESTED' BY MAINT THAT THE FMC'S WERE THE CAUSE OF THE PROBLEM; AS PER THE LOGBOOK. THE ACFT'S FUEL QUANTITY WAS NOT VERIFIED BY THE STICKS AND THE ACFT WAS CLRED FOR CONTINUED SVC; ACROSS THE OCEAN WITH NO CORRECTIVE ACTION TAKEN AND NO CAUSE FOR THE GLITCH IDENTIFIED OR FOUND. DURING THE DISCUSSIONS WITH MAINT CTL AND THE MECHANICS ON DUTY WE RAN OUT OF DUTY TIME TO CONTINUE ON TO DEST. (WE WERE ALREADY 2 HOURS LATE FROM A MECHANICAL AND HAD A 14+30 DUTY DAY PRIOR TO ANY PROBLEMS.) A PROBLEM OF THIS MAGNITUDE NEEDS TO BE ADDRESSED AND CORRECTIVE ACTION TAKEN TO IDENTIFY AND FIX THE PROBLEM. GIVEN THE INFO WE HAD; WE COULD HAVE BEEN FORCED INTO A SITUATION OF MAKING AN EMER LNDG AT NIGHT AT A STRANGE ARPT WITH NO LIGHTS ON THE RWY OR DITCH IN THE OCEAN. I MUST COMMEND MY CREW FOR TEAMWORK AND PROFESSIONALISM DISPLAYED DURING AN 'UNHEARD OF EMER SITUATION.'CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED IN HIS COMMUNICATION WITH OTHER PLTS RESULTED IN RPTS OF TWO NEARLY IDENTICAL INSTANCES ON SEPARATE ACFT IN THE FLEET. ONE HAPPENED ON FINAL TO THE PLANNED DEST BUT THE SECOND WAS SIMILAR TO THE RPTR'S INCIDENT WITH FUEL DROPPING ALMOST TO ZERO FROM A PERFECTLY NORMAL READING AT THE PREVIOUS REPORTING POINT. AGAIN; A FEAR OF A MASSIVE FUEL LEAK DROVE THE DECISION MAKING. IN THIS CASE THE FLT DIVERTED FOR AN EMER LNDG. THROUGH THEIR OWN INVESTIGATION; THE RPTR; A TRAINING CHK AIRMAN ON THE FLEET; LEARNED MAINT SUBSEQUENTLY REPLACED A UNIT REFERRED TO ONLY AS AN 'ELECTRICAL SYSTEM MODULE' WHICH CONTAINED ALLEGEDLY FAULTY SOFTWARE. THE RPTR WAS UNCERTAIN AS TO THE EFFECT IT HAS ON THE PROBLEM OR EVEN IF THE REASON FOR THE REPLACEMENT WAS A DIRECT CONSEQUENCE. THE RPTR IS CONCERNED THE ACR HAS MADE NO ATTEMPT TO DATE TO INFORM THE FLT CREWS OF THE POTENTIAL FOR THIS PROBLEM AND TO SPECIFY A SPECIAL PROC FOR ADDRESSING IT (THE PULLING AND RESETTING OF THE CIRCUIT BREAKERS) IN A RAPID AND SPECIFIC MANNER. THE RPTR REITERATED THE SERIOUSNESS OF THE COURSE OF ACTION ON WHICH THEY WERE ORIGINALLY COMMITTED; IE; LNDG AT A DARK; CLOSED ARPT WITHOUT BENEFIT OF ANY ELECTRONIC GUIDANCE IN ORDER TO AVOID A POSSIBLE ALL ENG FLAMEOUT DUE TO FUEL STARVATION. FINALLY; THE COMMON ELEMENT OF THESE EVENTS APPEARS TO BE A DRAMATIC DROP IN FUEL QUANTITY FROM A MASSIVE FUEL LEAK BUT; UPON EXAMINATION; SUBSEQUENT FUEL BURN FROM THAT POINT APPEARED CONSISTENT WITH NORMAL FUEL FLOW.

Data retrieved from NASA's ASRS site as of January 2009 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.