Narrative:

This was a cross country trip from home base to ZZZ. Departure was made with tanks filled (48 gallons usable). The previous trip had taken approximately 4 hours which allowed 40-45 mins reserve at 9.5-10 gph. However; with a headwind; I was using more fuel; so I continued to calculate fuel and lean. At the 1/2 way point; I knew fuel may be a concern and at 70-80 mi from my destination; I considered to use an early fuel stop. However; at this point the nearest airport was nearly as far as ZZZ. I continued on. As I ran 1 tank dry; I noticed that the gauge still indicated 3-5 gallons fuel. Knowing now that this would be close; I considered a field landing. I was still 30 mi out and thought hard about the risk of running out over a major river (1 mi wide between me and ZZZ). As I picked out a field; I reported my intentions to unicom and my low on fuel condition. The landing was smooth and without harm to persons or property. The property owner was farming in the same field and after notifying unicom of the successful landing; I explained the situation to the farmer. He agreed that no damage was done; so I fueled up and departed the same field with his permission. I then flew on to my destination. Because there was no property damage and there were no injuries and I had no passenger; I saw no need to make a report. However; I was later advised to file this report to NASA as a precautionary measure. I conclude that fuel gauges are not reliable and fuel burns can vary; however; I made a very poor assumption and should never allow fuel to get that low. I was fortunate to make a safe landing with no harm to persons or property. My personal fuel minimums will now allow for a 1 1/2 hour reserve.

Google
 

Original NASA ASRS Text

Title: PA28 PLT MADE A PRECAUTIONARY LNDG IN A FIELD AS A RESULT OF HIS LOW FUEL STATE.

Narrative: THIS WAS A XCOUNTRY TRIP FROM HOME BASE TO ZZZ. DEP WAS MADE WITH TANKS FILLED (48 GALLONS USABLE). THE PREVIOUS TRIP HAD TAKEN APPROX 4 HRS WHICH ALLOWED 40-45 MINS RESERVE AT 9.5-10 GPH. HOWEVER; WITH A HEADWIND; I WAS USING MORE FUEL; SO I CONTINUED TO CALCULATE FUEL AND LEAN. AT THE 1/2 WAY POINT; I KNEW FUEL MAY BE A CONCERN AND AT 70-80 MI FROM MY DEST; I CONSIDERED TO USE AN EARLY FUEL STOP. HOWEVER; AT THIS POINT THE NEAREST ARPT WAS NEARLY AS FAR AS ZZZ. I CONTINUED ON. AS I RAN 1 TANK DRY; I NOTICED THAT THE GAUGE STILL INDICATED 3-5 GALLONS FUEL. KNOWING NOW THAT THIS WOULD BE CLOSE; I CONSIDERED A FIELD LNDG. I WAS STILL 30 MI OUT AND THOUGHT HARD ABOUT THE RISK OF RUNNING OUT OVER A MAJOR RIVER (1 MI WIDE BTWN ME AND ZZZ). AS I PICKED OUT A FIELD; I RPTED MY INTENTIONS TO UNICOM AND MY LOW ON FUEL CONDITION. THE LNDG WAS SMOOTH AND WITHOUT HARM TO PERSONS OR PROPERTY. THE PROPERTY OWNER WAS FARMING IN THE SAME FIELD AND AFTER NOTIFYING UNICOM OF THE SUCCESSFUL LNDG; I EXPLAINED THE SITUATION TO THE FARMER. HE AGREED THAT NO DAMAGE WAS DONE; SO I FUELED UP AND DEPARTED THE SAME FIELD WITH HIS PERMISSION. I THEN FLEW ON TO MY DEST. BECAUSE THERE WAS NO PROPERTY DAMAGE AND THERE WERE NO INJURIES AND I HAD NO PAX; I SAW NO NEED TO MAKE A RPT. HOWEVER; I WAS LATER ADVISED TO FILE THIS RPT TO NASA AS A PRECAUTIONARY MEASURE. I CONCLUDE THAT FUEL GAUGES ARE NOT RELIABLE AND FUEL BURNS CAN VARY; HOWEVER; I MADE A VERY POOR ASSUMPTION AND SHOULD NEVER ALLOW FUEL TO GET THAT LOW. I WAS FORTUNATE TO MAKE A SAFE LNDG WITH NO HARM TO PERSONS OR PROPERTY. MY PERSONAL FUEL MINIMUMS WILL NOW ALLOW FOR A 1 1/2 HR RESERVE.

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.