Narrative:

We departed at approximately XA45 local and flew to a prebriefed area for a photo shoot 35nm south-southeast. After spending about 40 minutes in the area; I was told that the photos were complete and then headed back with my wingmen. As I was descending for landing; about 5 miles from the field; the engine suddenly began to run roughly. I checked the instruments and oil appeared to be normal. The engine continued to run rough and I wasn't certain if it would continue to run long enough for me to make it back to the airport. Rather than risk injury to myself or others in the town I decided to make a precautionary landing on the northbound lane of a highway. One of my wingmen stayed with me as an extra set of eyes while the other two continued to the airport. Being a sunday; the traffic was light and I was able to easily put the aircraft down safely on the highway. Once stopped I pushed the aircraft clear of the lanes so as to not impede traffic. The highway patrol arrived and I explained the situation. I determined that the aircraft was almost completely out of fuel. One of my mechanics quickly arrived; inspected the aircraft and determined that the aircraft suffered no damage and was safe to fly. I had a coworker bring out 14 gallons of fuel; which we put into the aircraft. I explained to the highway patrol that the aircraft was safe to fly and my mechanic verified that for them. I explained that if I wasn't able to takeoff soon; the aircraft would have to be either towed back to the airport through town or dismantled and trucked back to the airport because I would be dark in about another 45 minutes. After making several phone calls highway patrol told me that I had their permission and that I had to takeoff immediately. They briefly stopped the northbound traffic and allowed me to takeoff. I was less than 2 miles from the runway and was back on the ground at my airport in less than 90 seconds. I am not sure if I took off after legal sunset; but it was still light enough to safely conduct the flight. Chain of events: 1) over the winter when the aircraft was being rebuilt; we had the fuel tank and its plumbing modified. The primary fuel level instrument is a sight gage made out of tubing. I was not aware that the very top of the sight gage no longer indicated when the fuel tank was completely full as it did last year. With the redesign the tank will actually hold about 9 more gallons of fuel after the fuel reaches the top of the sight gage. I made the mistake of assuming that the tank was full and did not verify by visually looking inside of the filler cap before flight. 2) the tubing that was used for the sight gage is used because it is highly resistant and remains flexible over time. This particular type of tubing has a deep green tint to it and is easily readable in the daylight. The flight was conducted late in the afternoon when the light was low and it became much harder to read the level accurately due to the tinting. 3) I have a digital fuel computer installed that displays the fuel flow and fuel quantity remainder. It is a highly accurate instrument; but it requires that the correct amount of fuel in the tanks be entered manually prior to flight. I had entered an incorrect amount and was therefore getting false indications of the amount of fuel that I had remaining. Corrective actions taken: 1) I have had my mechanics replace all of the green-tinted tubing with clear tubing that is much easier to see; especially in low light. 2) I have verified exactly how much fuel the tank holds and how much more needs to be added and reach full capacity once the fuel level disappears from the top of the sight gage. 3) I have completely re calibrated the sight gage. 4) I will always visually confirm the fuel level by dipping the tanks.

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Original NASA ASRS Text

Title: Pitts pilot misjudged fuel available and ran out of fuel 5 miles from destination; a safe landing was made on a highway.

Narrative: We departed at approximately XA45 local and flew to a prebriefed area for a photo shoot 35nm south-southeast. After spending about 40 minutes in the area; I was told that the photos were complete and then headed back with my wingmen. As I was descending for landing; about 5 miles from the field; the engine suddenly began to run roughly. I checked the instruments and oil appeared to be normal. The engine continued to run rough and I wasn't certain if it would continue to run long enough for me to make it back to the airport. Rather than risk injury to myself or others in the town I decided to make a precautionary landing on the northbound lane of a Highway. One of my wingmen stayed with me as an extra set of eyes while the other two continued to the airport. Being a Sunday; the traffic was light and I was able to easily put the aircraft down safely on the highway. Once stopped I pushed the aircraft clear of the lanes so as to not impede traffic. The Highway Patrol arrived and I explained the situation. I determined that the aircraft was almost completely out of fuel. One of my mechanics quickly arrived; inspected the aircraft and determined that the aircraft suffered no damage and was safe to fly. I had a coworker bring out 14 gallons of fuel; which we put into the aircraft. I explained to the Highway Patrol that the aircraft was safe to fly and my Mechanic verified that for them. I explained that if I wasn't able to takeoff soon; the aircraft would have to be either towed back to the airport through town or dismantled and trucked back to the airport because I would be dark in about another 45 minutes. After making several phone calls Highway Patrol told me that I had their permission and that I had to takeoff immediately. They briefly stopped the northbound traffic and allowed me to takeoff. I was less than 2 miles from the runway and was back on the ground at my airport in less than 90 seconds. I am not sure if I took off after legal sunset; but it was still light enough to safely conduct the flight. Chain of Events: 1) Over the winter when the aircraft was being rebuilt; we had the fuel tank and its plumbing modified. The primary fuel level instrument is a sight gage made out of tubing. I was not aware that the very top of the sight gage no longer indicated when the fuel tank was completely full as it did last year. With the redesign the tank will actually hold about 9 more gallons of fuel after the fuel reaches the top of the sight gage. I made the mistake of assuming that the tank was full and did not verify by visually looking inside of the filler cap before flight. 2) The tubing that was used for the sight gage is used because it is highly resistant and remains flexible over time. This particular type of tubing has a deep green tint to it and is easily readable in the daylight. The flight was conducted late in the afternoon when the light was low and it became much harder to read the level accurately due to the tinting. 3) I have a digital fuel computer installed that displays the fuel flow and fuel quantity remainder. It is a highly accurate instrument; but it requires that the correct amount of fuel in the tanks be entered manually prior to flight. I had entered an incorrect amount and was therefore getting false indications of the amount of fuel that I had remaining. Corrective Actions Taken: 1) I have had my mechanics replace all of the green-tinted tubing with clear tubing that is much easier to see; especially in low light. 2) I have verified exactly how much fuel the tank holds and how much more needs to be added and reach full capacity once the fuel level disappears from the top of the sight gage. 3) I have completely re calibrated the sight gage. 4) I will always visually confirm the fuel level by dipping the tanks.

Data retrieved from NASA's ASRS site as of April 2012 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.