Narrative:

I'm a member of a club; which gives me access to four 172's. I typically fly one of the other three; which are all 160 hp models. On this trip; however; I would be carrying four adults and the airplane I took on that day was a 180 hp model. It was the only plane with enough useful load to carry all of us. So; I chose to fly an airplane that I had never flown before. I got some performance information from the club's website. (50 gal long range tanks; 8.7 gal/hour fuel burn; and a cruise speed of 128 KTS). I used those numbers to calculate that I could fly for 5 hours and 15 minutes before reaching my 30 minute reserve. I purchased an ipad and [flight planning software] earlier in the week and used that to calculate that the trip should only take just under four hours so I thought I had plenty of fuel. Once the flight was under way I learned that the cruise speed was more like 120 KTS (2;400 RPM) and the headwind was stronger than I had planned for and I was only achieving a ground speed of right around 100 KTS. However; my GPS told me that I would still be able to make my destination in less than five hours. I had failed to note our exact time of departure; but estimated.once we began to near [our destination] the fuel gauges began to dip near 'east' but I've never trusted fuel gauges in airplanes and instead trust my math to determine my range. So; I refused to believe the gauges and continued to proceed (although the gauges did make me a bit nervous). After I had contacted approach and they were routing me in preparation for landing; the engine cut out and started to idle. I immediately informed the controller that I had run out of fuel. He told me to look for the north/south highway and I did. While I looked I tried switching the fuel selector to left and to right. It had previously been set to both. This did not help. I found the highway and felt that I could make it as long as the engine didn't cut out completely and cause the prop to stop spinning. The engine did cut out completely once I was within a few hundred feet of the highway; but I had already made it at this point. I did go from 80 to 60 KTS instantly but still had enough altitude to recover. I touched down on the highway and was very fortunate that traffic was able to see me land and stopped behind me.in reflecting upon my mistakes that led to this incident; I can find many. To start with; I used numbers from the club website to do my trip calculations rather than consulting the poh. I did not confirm the accuracy of the numbers with other club members who had plenty of experience in the airplane. I had far too much confidence in numbers that I did not know from experience to be accurate. I failed to check the exact time of departure when we took off. I did not trust the fuel gauges when they were nearing empty. I've never trusted those gauges and assumed wrongly that they would go well under 'east' like most cars do. I was stubborn and believed that my math was correct and more accurate than the gauges. I failed to inform the controller upon initial contact that I had minimal fuel; even though the fact that the gauges were hovering over empty was making me nervous. Once the engine cut to an idle; I fixated on my airspeed and failed to try the carb heat to see if maybe carburetor icing was causing the engine to cut out rather than fuel starvation. I learned many valuable lessons from these mistakes and am very thankful that my friends and I are still here to benefit from what I've learned.

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Original NASA ASRS Text

Title: C172 pilot landed on a highway short of his destination due to inadequate fuel planning and monitoring.

Narrative: I'm a member of a club; which gives me access to four 172's. I typically fly one of the other three; which are all 160 HP models. On this trip; however; I would be carrying four adults and the airplane I took on that day was a 180 HP model. It was the only plane with enough useful load to carry all of us. So; I chose to fly an airplane that I had never flown before. I got some performance information from the club's website. (50 gal long range tanks; 8.7 gal/hour fuel burn; and a cruise speed of 128 KTS). I used those numbers to calculate that I could fly for 5 hours and 15 minutes before reaching my 30 minute reserve. I purchased an iPad and [flight planning software] earlier in the week and used that to calculate that the trip should only take just under four hours so I thought I had plenty of fuel. Once the flight was under way I learned that the cruise speed was more like 120 KTS (2;400 RPM) and the headwind was stronger than I had planned for and I was only achieving a ground speed of right around 100 KTS. However; my GPS told me that I would still be able to make my destination in less than five hours. I had failed to note our exact time of departure; but estimated.Once we began to near [our destination] the fuel gauges began to dip near 'E' but I've never trusted fuel gauges in airplanes and instead trust my math to determine my range. So; I refused to believe the gauges and continued to proceed (although the gauges did make me a bit nervous). After I had contacted Approach and they were routing me in preparation for landing; the engine cut out and started to idle. I immediately informed the Controller that I had run out of fuel. He told me to look for the north/south highway and I did. While I looked I tried switching the fuel selector to Left and to Right. It had previously been set to Both. This did not help. I found the highway and felt that I could make it as long as the engine didn't cut out completely and cause the prop to stop spinning. The engine did cut out completely once I was within a few hundred feet of the highway; but I had already made it at this point. I did go from 80 to 60 KTS instantly but still had enough altitude to recover. I touched down on the highway and was very fortunate that traffic was able to see me land and stopped behind me.In reflecting upon my mistakes that led to this incident; I can find many. To start with; I used numbers from the club website to do my trip calculations rather than consulting the POH. I did not confirm the accuracy of the numbers with other club members who had plenty of experience in the airplane. I had far too much confidence in numbers that I did not know from experience to be accurate. I failed to check the exact time of departure when we took off. I did not trust the fuel gauges when they were nearing empty. I've never trusted those gauges and assumed wrongly that they would go well under 'E' like most cars do. I was stubborn and believed that my math was correct and more accurate than the gauges. I failed to inform the controller upon initial contact that I had minimal fuel; even though the fact that the gauges were hovering over empty was making me nervous. Once the engine cut to an idle; I fixated on my airspeed and failed to try the carb heat to see if maybe carburetor icing was causing the engine to cut out rather than fuel starvation. I learned many valuable lessons from these mistakes and am very thankful that my friends and I are still here to benefit from what I've learned.

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.