Narrative:

On aug/xx/95 I conducted a VFR flight from three forks, mt, to ogden, ut. A VFR flight plan was filed with bzn FSS via telephone. The flight was planned for 3 hours, 10 mins at cruise altitude of 10500 ft MSL. The tanks were topped via fuel truck (2) X 12.5 us gallons (25 gallons useable) earlier in the day, which would provide 4 hours, 10 mins based on consumption of 6 gallons per hour. The flight departed three forks and proceeded as planned. Apchiing tremonton, ut, cedar city radio was notified and the flight plan was extended an additional 15 mins, due to unforecasted headwinds. During the flight, fuel selection was alternated as usual between left and right tanks for proper fuel balance. Approaching the area near willard, ut, while descending through 8500 ft MSL, slc approach control was contacted and radar contact was established. Shortly afterward the left tank ran dry and I selected the right tank which was expected to contain my reserve fuel aboard. Since the flight had run 15 mins longer than anticipated, I elected to proceed to the bmc airport which was now approximately 10 mi behind me. I advised approach I was reversing course to bmc and I made a 180 degree turn toward it when the second tank appeared to run dry. I advised slc approach of our situation and told them I would be landing on I-15 just south of bmc. We landed on I-15 3 hours and 26 mins after takeoff, without damage to the aircraft or property nor injuries to myself or my wife. The aircraft was fueled, inspected, and was flown to its home base (ogd) the next morning. I'm the owner of the aircraft and I've determined the consumption of 6 gallons of fuel used per hour is a very realistic number. The fuel consumption figures published in the 1967 cessna 150 pilot manual (continental 0-200-a engine) are substantially less than the 6 gallon figure I use. The total elapsed time of the flight (verified by great falls FSS and utah highway patrol) was 3 hours, 26 mins. I've been prudent in my flight planning and preparation through the past 30 yrs and 20000 hours of accident/incident free flying. I'm looking at all possibilities why the aircraft was only aloft for 3 hours, 26 mins instead of the expected 4 hours, 10 mins. The aircraft sat on the ramp all afternoon with the ramp temperatures nearing or exceeding 100 degrees F. Fuel venting is also a possibility.

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Original NASA ASRS Text

Title: FORCED LNDG. OUT OF GAS.

Narrative: ON AUG/XX/95 I CONDUCTED A VFR FLT FROM THREE FORKS, MT, TO OGDEN, UT. A VFR FLT PLAN WAS FILED WITH BZN FSS VIA TELEPHONE. THE FLT WAS PLANNED FOR 3 HRS, 10 MINS AT CRUISE ALT OF 10500 FT MSL. THE TANKS WERE TOPPED VIA FUEL TRUCK (2) X 12.5 U.S. GALLONS (25 GALLONS USEABLE) EARLIER IN THE DAY, WHICH WOULD PROVIDE 4 HRS, 10 MINS BASED ON CONSUMPTION OF 6 GALLONS PER HR. THE FLT DEPARTED THREE FORKS AND PROCEEDED AS PLANNED. APCHIING TREMONTON, UT, CEDAR CITY RADIO WAS NOTIFIED AND THE FLT PLAN WAS EXTENDED AN ADDITIONAL 15 MINS, DUE TO UNFORECASTED HEADWINDS. DURING THE FLT, FUEL SELECTION WAS ALTERNATED AS USUAL BTWN L AND R TANKS FOR PROPER FUEL BAL. APCHING THE AREA NEAR WILLARD, UT, WHILE DSNDING THROUGH 8500 FT MSL, SLC APCH CTL WAS CONTACTED AND RADAR CONTACT WAS ESTABLISHED. SHORTLY AFTERWARD THE L TANK RAN DRY AND I SELECTED THE R TANK WHICH WAS EXPECTED TO CONTAIN MY RESERVE FUEL ABOARD. SINCE THE FLT HAD RUN 15 MINS LONGER THAN ANTICIPATED, I ELECTED TO PROCEED TO THE BMC ARPT WHICH WAS NOW APPROX 10 MI BEHIND ME. I ADVISED APCH I WAS REVERSING COURSE TO BMC AND I MADE A 180 DEG TURN TOWARD IT WHEN THE SECOND TANK APPEARED TO RUN DRY. I ADVISED SLC APCH OF OUR SIT AND TOLD THEM I WOULD BE LNDG ON I-15 JUST S OF BMC. WE LANDED ON I-15 3 HRS AND 26 MINS AFTER TKOF, WITHOUT DAMAGE TO THE ACFT OR PROPERTY NOR INJURIES TO MYSELF OR MY WIFE. THE ACFT WAS FUELED, INSPECTED, AND WAS FLOWN TO ITS HOME BASE (OGD) THE NEXT MORNING. I'M THE OWNER OF THE ACFT AND I'VE DETERMINED THE CONSUMPTION OF 6 GALLONS OF FUEL USED PER HR IS A VERY REALISTIC NUMBER. THE FUEL CONSUMPTION FIGURES PUBLISHED IN THE 1967 CESSNA 150 PLT MANUAL (CONTINENTAL 0-200-A ENG) ARE SUBSTANTIALLY LESS THAN THE 6 GALLON FIGURE I USE. THE TOTAL ELAPSED TIME OF THE FLT (VERIFIED BY GREAT FALLS FSS AND UTAH HWY PATROL) WAS 3 HRS, 26 MINS. I'VE BEEN PRUDENT IN MY FLT PLANNING AND PREPARATION THROUGH THE PAST 30 YRS AND 20000 HRS OF ACCIDENT/INCIDENT FREE FLYING. I'M LOOKING AT ALL POSSIBILITIES WHY THE ACFT WAS ONLY ALOFT FOR 3 HRS, 26 MINS INSTEAD OF THE EXPECTED 4 HRS, 10 MINS. THE ACFT SAT ON THE RAMP ALL AFTERNOON WITH THE RAMP TEMPS NEARING OR EXCEEDING 100 DEGS F. FUEL VENTING IS ALSO A POSSIBILITY.

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.