Narrative:

I was flying my PA28-140 on about a 2 hour trip (depending on the winds). I was about 9 miles from my destination when the engine acted like it was running out of fuel and I made a successful emergency landing on [the highway] in the northbound lanes with no injuries to anyone or damage to the plane. Three days prior I topped off both of the tanks on the plane which hold 25 gallons per tank for a total of 50 gallons. After I started the engine I reset the flight timer before leaving on a trip that trip took 2.2 hours.the day of the trip; I did my normal preflight check prior to leaving and everything looked normal including the amount of fuel in the tanks (a visual check) and departed early evening. The weather was good with just a few clouds with light to calm winds for the entire flight. I used flight following for the entire trip until I could see the beacon at my destination. I flew at 6;500 ft for most of the trip and had about an average of a 5-10 knot headwind. I estimated that the flight should have taken 2 hours to my destination. After having the airport's beacon in sight I canceled flight following and switched to CTAF. At that point (about 1:55 minutes into the flight) the plane's engine started to quit. I switched from the left tank to the right tank and the engine started up again. At this point I realized something was not right because I should not have exhausted all of the fuel in the left tank. Using a flashlight; I checked my fuel gauges and saw that they were both reading near empty; but I thought I would be able to get to the airport without any problems. There was a plane getting ready to depart runway X and then it was going to turn to the west. I called them and asked which direction they were going to turn. He responded that he was going to make a left turn out; which would have put him between the airport and me. At first I thought this would be fine but I changed my mind and asked if they would please turn right and told them I had minimum fuel and needed to land on runway xx and he agreed without hesitation. At this point I was at 3;500 ft MSL and 5 miles from my destination and the engine started to quit again. I turned on the electric fuel pump and the engine restarted. Within a few seconds it quit once more. I declared an emergency and stated that my engine was out. Fortunately I was able to successfully land the plane on a highway without injuring anyone or damaging the plane or anything else. The plane holds 48 gallons of usable fuel (50 gallons total) and my normal fuel burn is about 9 gallons per hour. 48 gallons divided by 9 should have yielded 5.33 hours of flight which is 5:20 minutes. I should have had 3.1 hours of fuel when I departed which should have been enough with plenty to spare.

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Original NASA ASRS Text

Title: A PA-28 Pilot became distracted while fueling his aircraft and two days later when the engine quit from fuel starvation he realized he became distracted while previously fueling and added fuel to only one tank.

Narrative: I was flying my PA28-140 on about a 2 hour trip (depending on the winds). I was about 9 miles from my destination when the engine acted like it was running out of fuel and I made a successful emergency landing on [the highway] in the northbound lanes with no injuries to anyone or damage to the plane. Three days prior I topped off both of the tanks on the plane which hold 25 gallons per tank for a total of 50 gallons. After I started the engine I reset the flight timer before leaving on a trip that trip took 2.2 hours.The day of the trip; I did my normal preflight check prior to leaving and everything looked normal including the amount of fuel in the tanks (a visual check) and departed early evening. The weather was good with just a few clouds with light to calm winds for the entire flight. I used Flight Following for the entire trip until I could see the beacon at my destination. I flew at 6;500 FT for most of the trip and had about an average of a 5-10 knot headwind. I estimated that the flight should have taken 2 hours to my destination. After having the airport's beacon in sight I canceled Flight Following and switched to CTAF. At that point (about 1:55 minutes into the flight) the plane's engine started to quit. I switched from the left tank to the right tank and the engine started up again. At this point I realized something was not right because I should not have exhausted all of the fuel in the left tank. Using a flashlight; I checked my fuel gauges and saw that they were both reading near empty; but I thought I would be able to get to the airport without any problems. There was a plane getting ready to depart Runway X and then it was going to turn to the west. I called them and asked which direction they were going to turn. He responded that he was going to make a left turn out; which would have put him between the airport and me. At first I thought this would be fine but I changed my mind and asked if they would please turn right and told them I had minimum fuel and needed to land on Runway XX and he agreed without hesitation. At this point I was at 3;500 FT MSL and 5 miles from my destination and the engine started to quit again. I turned on the electric fuel pump and the engine restarted. Within a few seconds it quit once more. I declared an emergency and stated that my engine was out. Fortunately I was able to successfully land the plane on a highway without injuring anyone or damaging the plane or anything else. The plane holds 48 gallons of usable fuel (50 gallons total) and my normal fuel burn is about 9 gallons per hour. 48 gallons divided by 9 should have yielded 5.33 hours of flight which is 5:20 minutes. I should have had 3.1 hours of fuel when I departed which should have been enough with plenty to spare.

Data retrieved from NASA's ASRS site as of July 2013 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.