On January 14, 2007 about 1610 Pacific standard time, a Navion (G model) airplane, N3BP, sustained substantial damage during an uncontrolled descent and subsequent collision with terrain, about 1 mile west of Douthitt Strip Airport (23CN), El Centro, California. The airplane was being operated as a visual flight rules (VFR) cross-country flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The private pilot, who also owned the airplane, and passenger sustained serious injuries. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated from Salinas Municipal Airport (SNS), Salinas, California, and was destined for 23CN. In a written statement, the pilot reported that after an uneventful flight from SNS, he initiated a normal approach to 23CN. While on final approach to runway 22, he stated that he couldn't see the runway or area surrounding it due to the alignment of the sun and decided to abort the landing and go-around. Shortly after applying power and raising the landing gear, the engine "sputtered" and lost power. The pilot stated that he had limited visibility due to the sun glare during the forced landing and was trying to keep the airplane from stalling. Subsequently, the airplane impacted terrain. Examination of the airframe and engine were conducted on February 2, 2007. Examination of the airframe revealed that the left and right wing sustained substantial damage. The recovery personnel reported that the right fuel tank was intact and contained about 10 gallons of fuel. All of the remaining fuel tanks were breeched. Examination of the fuel selector valve revealed that it was in the main fuel tank position and the shaft was bent. Manual activation of the fuel selector valve by hand produced positive engagement in all positions. The engine was removed from the airframe and installed on an engine run test stand. To facilitate an engine test run, the number five cylinder rocker box cover and an inlet fuel line to the fuel pump were replaced. Tape was applied over a hole in the number five cylinder intake tube. The engine driven fuel pump was removed from the engine and the fuel pump drive coupling was intact. The fuel pump drive shaft rotated freely when manually actuated by hand. The fuel pump was reinstalled on the engine. The engine was successfully run at various power settings with no anomalies noted. The fuel selector valve was removed from the airframe and sent to Sierra Hotel Aero Inc. of St. Paul, Minnesota for further examination. On April 11, 2007, under the supervision of a Federal Aviation Administration (FAA) inspector the fuel selector valve was examined. The fuel selector valve was placed on a test bench and functionally tested in accordance with the Navion Service Bulletin 106. Approximately 24 inches of vacuum pressure was applied in all operating positions. During the test, an amount in excess of 20 inches of mercury was lost within one minute in all positions after pressure was applied. According to the Type Certificate Holder for the airplane, this exceeded parameters (maximum specified loss is 1 inch). Both internal and external leakage of the fuel selector valve was observed during the test. The fuel selector valve was disassembled and inspected. No further anomalies were noted. According to the US Naval Observatory, Astronomical Applications Department, the time of sunset was 1658 and the end of civil twilight was 1725.