Narrative:

I visually checked the fuel level before this flight. It appeared full; on both sides. I had also asked the lineman; a few days earlier; to top the fuel tanks and he agreed to. While the fuel was not touching the fuel caps; I guessed that he had left 'room' for expansion; to avoid it running onto the hangar floor. I flew for approximately three hours; at which point the aircraft lost power. (It should have only burned approximately 27 gallons in three hours. It either burned more than 9 gallons/hour or it was not as full as it appeared; because the usable fuel quantity for this aircraft is 38 gallons. The right gauge even indicated 1/4 full). So; at 3;500 ft MSL; when the aircraft lost power; I immediately turned toward the closest airport and glided as far as possible. I banked back and forth; checked fuel settings; changed tanks; checked mixture; etc. And it then regained power for approximately 30 seconds; then completely quit. I thought we might make it to the airport; but when it was clear that that wouldn't be possible; I selected a field that looked level; without trees. I ended up making a smooth landing; but in a wheat field. No damage occurred to the aircraft and thankfully; no one was injured. While fuel is always the responsibility of the P.I.C.; the reality is the lineman failed to top it off. It was evidently approximately 10 gallons less than full; but the exact amount is impossible to ascertain with a visual inspection. The best lesson here is that if the fuel is not touching the fuel caps; it is imperative to use a fuel stick to get an accurate measurement of the fuel level. It is impossible to know how much fuel is in the tanks otherwise. I will always use a fuel stick in the future if the fuel is not touching the caps.

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Original NASA ASRS Text

Title: The pilot of a Cessna 172M had an engine failure after approximately 3 hours of flight and made an off-field emergency landing.

Narrative: I visually checked the fuel level before this flight. It appeared full; on both sides. I had also asked the lineman; a few days earlier; to top the fuel tanks and he agreed to. While the fuel was not touching the fuel caps; I guessed that he had left 'room' for expansion; to avoid it running onto the hangar floor. I flew for approximately three hours; at which point the aircraft lost power. (It should have only burned approximately 27 gallons in three hours. It either burned more than 9 gallons/hour or it was not as full as it appeared; because the usable fuel quantity for this aircraft is 38 gallons. The right gauge even indicated 1/4 full). So; at 3;500 FT MSL; when the aircraft lost power; I immediately turned toward the closest airport and glided as far as possible. I banked back and forth; checked fuel settings; changed tanks; checked mixture; etc. and it then regained power for approximately 30 seconds; then completely quit. I thought we might make it to the airport; but when it was clear that that wouldn't be possible; I selected a field that looked level; without trees. I ended up making a smooth landing; but in a wheat field. No damage occurred to the aircraft and thankfully; no one was injured. While fuel is always the responsibility of the P.I.C.; the reality is the lineman failed to top it off. It was evidently approximately 10 gallons less than full; but the exact amount is impossible to ascertain with a visual inspection. The best lesson here is that if the fuel is not touching the fuel caps; it is imperative to use a fuel stick to get an accurate measurement of the fuel level. It is impossible to know how much fuel is in the tanks otherwise. I will always use a fuel stick in the future if the fuel is not touching the caps.

Data retrieved from NASA's ASRS site 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.