Narrative:

This flight was in an small aircraft that ended with a forced landing approximately 30 mi east of albuquerque on I-40. Fuel exhaustion forced the landing, but with less than 4 hours of flight time on long-range tanks, this unusually high rate of fuel consumption has not been determined. The flight originated on full tanks (88 gallons usable) and should, therefore, perform to nearly 5 hours cruise with 45 min reserve. During the flight, all pressures, temperatures, and fuel flow indications were normal, however the fuel gauges appear to be sticking at certain levels. Because of this, I monitored fuel consumption by switching tanks every hour and leaning the mixture to 90 pounds per hour fuel flow. During a routine flow check, I noticed abnormally low fuel quantity in both tanks. This was the first indication that I might have a problem, but as mentioned earlier, the gauges were not giving me completely accurate information previously in the flight. With all other system functioning normally, I continued the flight. At this point, I was inside the anton chico VOR about halfway to ruins intersection. I could see the lights of albuquerque and felt that it was the nearest lit airport in my vicinity, so I pulled the power and mixture to a best economy setting and continued. Within mins, the right tank ran dry and the engine died. I switched tanks only to find the left tank empty also. I reported the problem to center and headed for the nearest airport, moriarty, NM, an unlit field about 12 mi ahead. Because of the darkness, I kept the aircraft over the interstate until I could hopefully see the airport. It became apparent that I was not going to make moriarty, so I landed the plane on the highway with no injuries, relatively little damage, and approximately 25 gallons of fuel unaccounted for. Of course, the investigation has not ended but speculations from the a&P and the FAA inspector include: 1) the fuel system pressurized the tanks, pumping fuel overboard. 2) fuel tank vents, found to be stuck wide open, allowed a siphon to form, sucking fuel out of the tanks. 3) a compression check found the #5 cylinder low at 28 psi. As far as what I could have done to prevent this landing, I honestly don't know. I followed the book. I ran the engine at 67%, and all system checked. At the point where I thought I might have a problem, albuquerque was my nearest airport, and I tried to make it. After the occurrence, the FAA inspector and I did some figuring and found that even if I had run the plane full-rich, I should not have exhausted the fuel in 3.9 hours. I understand that there is a pending airworthiness directive on the fuel system, and that this is not the first problem of its kind. If there is information on this, I would greatly appreciate copies or information on how to acquire it.

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Original NASA ASRS Text

Title: SMA MAKES EMER LNDG ON HWY AT NIGHT WHEN ENG QUITS DUE FUEL EXHAUSTION.

Narrative: THIS FLT WAS IN AN SMA THAT ENDED WITH A FORCED LNDG APPROX 30 MI E OF ALBUQUERQUE ON I-40. FUEL EXHAUSTION FORCED THE LNDG, BUT WITH LESS THAN 4 HRS OF FLT TIME ON LONG-RANGE TANKS, THIS UNUSUALLY HIGH RATE OF FUEL CONSUMPTION HAS NOT BEEN DETERMINED. THE FLT ORIGINATED ON FULL TANKS (88 GALLONS USABLE) AND SHOULD, THEREFORE, PERFORM TO NEARLY 5 HRS CRUISE WITH 45 MIN RESERVE. DURING THE FLT, ALL PRESSURES, TEMPS, AND FUEL FLOW INDICATIONS WERE NORMAL, HOWEVER THE FUEL GAUGES APPEAR TO BE STICKING AT CERTAIN LEVELS. BECAUSE OF THIS, I MONITORED FUEL CONSUMPTION BY SWITCHING TANKS EVERY HR AND LEANING THE MIXTURE TO 90 POUNDS PER HR FUEL FLOW. DURING A ROUTINE FLOW CHK, I NOTICED ABNORMALLY LOW FUEL QUANTITY IN BOTH TANKS. THIS WAS THE FIRST INDICATION THAT I MIGHT HAVE A PROBLEM, BUT AS MENTIONED EARLIER, THE GAUGES WERE NOT GIVING ME COMPLETELY ACCURATE INFO PREVIOUSLY IN THE FLT. WITH ALL OTHER SYS FUNCTIONING NORMALLY, I CONTINUED THE FLT. AT THIS POINT, I WAS INSIDE THE ANTON CHICO VOR ABOUT HALFWAY TO RUINS INTXN. I COULD SEE THE LIGHTS OF ALBUQUERQUE AND FELT THAT IT WAS THE NEAREST LIT ARPT IN MY VICINITY, SO I PULLED THE PWR AND MIXTURE TO A BEST ECONOMY SETTING AND CONTINUED. WITHIN MINS, THE R TANK RAN DRY AND THE ENG DIED. I SWITCHED TANKS ONLY TO FIND THE L TANK EMPTY ALSO. I RPTED THE PROBLEM TO CTR AND HEADED FOR THE NEAREST ARPT, MORIARTY, NM, AN UNLIT FIELD ABOUT 12 MI AHEAD. BECAUSE OF THE DARKNESS, I KEPT THE ACFT OVER THE INTERSTATE UNTIL I COULD HOPEFULLY SEE THE ARPT. IT BECAME APPARENT THAT I WAS NOT GOING TO MAKE MORIARTY, SO I LANDED THE PLANE ON THE HWY WITH NO INJURIES, RELATIVELY LITTLE DAMAGE, AND APPROX 25 GALLONS OF FUEL UNACCOUNTED FOR. OF COURSE, THE INVESTIGATION HAS NOT ENDED BUT SPECULATIONS FROM THE A&P AND THE FAA INSPECTOR INCLUDE: 1) THE FUEL SYS PRESSURIZED THE TANKS, PUMPING FUEL OVERBOARD. 2) FUEL TANK VENTS, FOUND TO BE STUCK WIDE OPEN, ALLOWED A SIPHON TO FORM, SUCKING FUEL OUT OF THE TANKS. 3) A COMPRESSION CHK FOUND THE #5 CYLINDER LOW AT 28 PSI. AS FAR AS WHAT I COULD HAVE DONE TO PREVENT THIS LNDG, I HONESTLY DON'T KNOW. I FOLLOWED THE BOOK. I RAN THE ENG AT 67%, AND ALL SYS CHKED. AT THE POINT WHERE I THOUGHT I MIGHT HAVE A PROBLEM, ALBUQUERQUE WAS MY NEAREST ARPT, AND I TRIED TO MAKE IT. AFTER THE OCCURRENCE, THE FAA INSPECTOR AND I DID SOME FIGURING AND FOUND THAT EVEN IF I HAD RUN THE PLANE FULL-RICH, I SHOULD NOT HAVE EXHAUSTED THE FUEL IN 3.9 HRS. I UNDERSTAND THAT THERE IS A PENDING AIRWORTHINESS DIRECTIVE ON THE FUEL SYS, AND THAT THIS IS NOT THE FIRST PROBLEM OF ITS KIND. IF THERE IS INFO ON THIS, I WOULD GREATLY APPRECIATE COPIES OR INFO ON HOW TO ACQUIRE IT.

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.