On May 26, 1996, at 1729 Pacific daylight time, N174HA, a Hiller UH-12 helicopter, operated by Blue Mountain Aviation, Inc., collided with terrain and was substantially damaged during an emergency landing near Walla Walla, Washington. The emergency landing was precipitated by a total loss of engine power during cruise. The commercial pilot and his passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed. The business flight was conducted under 14 CFR 91. The pilot reported that he exhausted his fuel supply while attempting to land at the Walla Walla Regional Airport for refueling. The pilot had previously attempted to refuel at a remote landing zone equipped with a fuel truck, but the fuel truck was unable to pump fuel at that time. The pilot and the owner of the operation boarded the helicopter and decided to fly to the airport with the low fuel levels that was contained in the helicopter. They stated that they had about 14 gallons of fuel on board. The pilot intended on landing the helicopter if the fuel gauge reached the "yellow" range during the flight. About 2.5 nautical miles from the airport, when the fuel gauge needle was slightly outside of the yellow range, the engine "quit." The pilot executed an immediate autorotation. One of the helicopter's skids impacted soft terrain during the landing and a main rotor blade struck the ground. The helicopter rolled over and was substantially damaged.