On May 28, 2004, at approximately 1920 mountain daylight time, a Lockheed TV-2, N6617, operated by ATG Flight Services Inc., was substantially damaged when it overran the runway and struck a ditch during a precautionary landing at Calhan Airport (5V4), Calhan, Colorado. The airline transport certificated pilot, and his airline transport certificated passenger were not injured. Visual meteorological conditions prevailed. An instrument flight rules (IFR) flight plan was filed for the positioning flight being conducted under Title 14 CFR Part 91. The flight to Denver, Colorado, originated at Salina, Kansas, at approximately 1845. According to the pilot, at approximately 1910, 45 nautical miles southeast of Centennial Airport (APA), his intended destination, the wing tip tank low fuel light illuminated. He stated that this was as planned, and he selected the 150-gallon wing tank. However, approximately 2 minutes later, the low fuel light illuminated for the wing tank. A "drop" in the fuel quantity indication on the main fuselage tank gauge confirmed the wing tanks' low fuel condition. He then selected the 100-gallon leading edge tank, and within a few minutes, its low fuel light illuminated as well. Again, he noted a "drop" in the fuel quantity indicated on the main fuselage tank gauge, confirming the leading edge tanks' low fuel condition. The pilot immediately contacted Denver Air Route Traffic Control Center (ARTCC), reported a "fuel emergency," and stated that he was going to land at the nearby Calhan Airport. The pilot made a precautionary landing at Calhan, on runway 35 (4,565 feet long by 50 feet wide, dirt strip, at an elevation of 6,450 feet msl). Upon landing, he retracted the flaps and applied full brakes; however, the airplane departed the end of the runway, struck a ditch, and slid approximately 400 feet, coming to a stop in an open field. The pilot shut down the engine and they both egressed. The impact with the ditch collapsed and separated both main landing gear assemblies from the wing spar. The airplane sustained substantial damage to both wing spars and the lower aft fuselage. According to the pilot, the airplane departed Salina, Kansas, with a fuel quantity of approximately 700 gallons of Jet A fuel. Prior to evacuating the airplane, he noted that the main fuselage tank gauge indicated approximately 68 gallons of fuel. During an examination of the wreckage, approximately 56 gallons of fuel was recovered. No fuel leaks were noted during the refueling at Salina or at the accident site. According to a representative from ATG Flight Services Inc., although no aircraft anomalies were noted, a stuck fuel tank float valve during fuel pump operation would allow fuel to "drain out of the saber vents at approximately 30 gallons per minute." The representative also stated that, the calculated fuel lost during approximately 8 minutes of fuel pump operation, which includes 5 minutes during the departure and initial climb from Salina and approximately 3 minutes following the initial wing tip tank low fuel light illumination, correlates to the amount of unaccountable fuel.