On December 9, 2009, about 1400 mountain standard time, a Beech 35-33, N316Z, was substantially damaged during a forced landing following a reported loss of engine power near Lehi, Utah. The airplane was registered to Omni-Air LLC of Washington, Utah, and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot, sole occupant of the airplane, was seriously injured. Visual meteorological conditions prevailed and no flight plan was filed for the cross-country flight. The flight originated from the St. George Municipal Airport, St. George, Utah, about 1230 with an intended destination of the South Valley Regional Airport (U42), Salt Lake City, Utah. Witnesses located at a Fixed Base Operator (FBO) at U42 reported that while monitoring the Common Traffic Advisory Frequency, 122.7 Megahertz, they overheard a mayday radio transmission stating, “Mayday mayday, I am at the point of the mountain, 5,100 feet, my engine just quit.” A certificated flight instructor (CFI) responded to the mayday call and told the pilot to verify that the fuel selector was on the fullest tank, the fuel was on, the mixture was full rich, and the magnetos were on both. The CFI then asked the pilot for the airplane’s registration number and if he had copied. No further radio transmissions were received from the pilot. A helicopter flying nearby also heard the mayday call and proceeded towards the location of the mountain. The pilot of the helicopter reported that they observed the downed airplane just south of the mountain. According to local law enforcement, witnesses located near the accident site reported observing the airplane on a westerly heading near Interstate 15, then suddenly banking to the right to a northerly heading before descending into terrain. In post-accident interviews, family members of the pilot reported that the pilot did not remember the accident flight or accident sequence. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that it came to rest upright in a grassy, snow-covered area between Interstate 15 and a southbound highway off-ramp at an elevation of about 4,625 feet mean sea level (msl). The left wing was bent upwards about 45 degrees approximately mid-span, and the fuselage was buckled aft of the cabin area. The inspector stated that the fuel selector valve was observed in the, “right main” position. Fuel was observed in the left and right main fuel tanks at the accident site. The airplane was recovered to a secure location for further examination. The wreckage recovery company reported that during recovery efforts, about 36 gallons of aviation fuel was removed from the left and right main wing tanks (about 18 gallons per side) and a minimal amount of fuel was recovered from the auxiliary fuel tanks on the left and right wings. The recovered engine and airframe were examined by representatives from Teledyne Continental Motors (TCM), and the FAA under the supervision of the Safety Board investigator-in-charge. Examination of the recovered airframe revealed that the left and right wings were removed from the airframe to facilitate wreckage transport. The left and right fuel main and auxiliary tanks were filled with water during the wreckage examination to verify the integrity of the fuel tanks. No evidence of leaks was observed. During the removal process of the fuel selector valve, a liquid consistent with fuel was observed within the left auxiliary fuel tank inlet line and fuel lines from the fuel selector to the engine pump supply and auxiliary fuel boost pump fuel lines. The fuel selector valve was removed and examined. Fuel was drained from the fuel selector valve airframe fuel sump. The fuel removed was found to be free of debris, and a sample tested negative for water using water-finding paste. The airframe fuel filter housing was removed and the filter was found free of debris. The fuel lines to the left and right auxiliary and main fuel tanks were free of debris. Air pressure was applied to all of the fuel lines with no blockages noted. The left and right main fuel tank screens were free of debris. The auxiliary fuel pump switch was found in the "OFF" position. The auxiliary fuel pump was removed and appeared intact. The inlet side of the pump was placed within water and battery power was applied to the pump. Water flowed throughout the pump normally. The engine was removed from the airframe and shipped to the facilities of TCM, Mobile, Alabama for further examination. Further examination of the engine at the facilities of TCM revealed that due to impact damage, the fuel control unit, oil sump, starter adapter, and parts of the induction system had to be replaced. The engine was subsequently installed on a test cell and was successfully started. The engine was run at various RPM settings for about 25 to 30 minutes. Throughout the duration of the engine run, the throttle was advanced from idle to full throttle six times with no anomalies noted. A leak was observed from the fuel pump adjustable orifice assembly; however it appeared to have no affect on the engine's ability to produce rated power. A second engine run was performed with the original fuel control unit installed on the engine. The engine was run throughout various RPM settings with no anomalies noted. The engine driven fuel pump did not exhibit any fuel leaks during the second engine run. The engine driven fuel pump was subsequently removed from the engine and installed on a test bench. The fuel pump was tested and functioned properly throughout its full range of operation. No leaks were observed during the entire test process.