20071206829089A

(-23) Aircraft was on its 23rd hour of phase 1 flight time under a special airworthiness certificate issued 10-12-2007. The aircraft left marana regional airport and began climbing east towards la cholla airpark. At approximately 5500 ft the engine power was reduced and the pilot began trimming the aircraft to cruise flight. The engine made a popping noise and within a few prop turns the engine froze, stopping with the prop in a horizontal position. The pilot attempted to restart the engine, but the engine would not even turn. The pilot states that all engine temps and pressures were within normal ranges prior to the engine quitting. The pilot set the aircraft to the recommended glide airspeed of 70MPH and attempted to glide to la cholla airpark which was a few miles away. When she realized the aircraft would not make it to the airport she selected a landing area on a local road. The pilot maneuvered the aircraft in a right hand turn to line up with the north-south running road. As the aircraft completed its right hand turn to the south she realized there was unsufficient turn radius to be able to align with the road. The aircraft was in a shallow right turn and approximately 36 feet to the east of the road when it contacted trees with the right hand wing. The right wing broke off outboard of the landing gear and it spun around 180 degrees to the right. As it continued to the ground the left hand wing tip contacted the ground and broke the spar outboard of the landing gear. The aircraft came to a final rest facing backwards towards the original flight path. The pilot was able to crawl from the aircraft and incurred minor injuries of several bumps and a sore shoulder from the five point seatbelt she had worn. Review of the aircraft wreckage noted there was no power being produced by the engine at the time of impact. The propeller was frozen in the horizontal position. Fuel was found in both tanks of the aircraft. On December 14 and 27 the engine was examined by this investigator. Fuel was drained from the fuel strainer and fuel was present in the fuel lines to the fuel pump. The fuel pressure indicator had broken from the carburetor at the time of impact. No fuel was found in the line from the fuel pump to the carburetor because of the separation of the pressure indicator. Removal of the carburetor showed there was fuel in the carburetor bowl and the throttle valve and mixture controls worked freely. There were no restrictions to the air intake filter other than dirt which had been picked up during impact. The carburetor mounting flange had separated from the engine upon impact, and the air diffuser of the engine had several breaches of the case which were caused by the case contacting the engine mount during the impact. The engine was broken free of the engine mount in all but one mounting spot. The magnetos, plug wires, and sparkplugs were intact. Removal and inspection of the sparkplugs indicate they were all firing with a correct fuel/air mixture. The oil reservoir was intact and contained oil to just below the max fill line (5 gal). Accessories were removed from the accessory case, and no abnormalities were found in the magnetos, starter, or generator. The accessory case was removed from the back of the engine. There was damage to the air diffuser section of the accessory case but otherwise no damage was found to the internal gears or housing. The cam gear and valve operating system was found intact, with no visible defects. The cylinders were examined and there were bulges found in the cylinder skirt base area on #5 and #3 cylinders. The propeller was removed and the forward case of the engine was opened. It was found that the #3 articulating connecting rod had separated from both the master rod and the bottom of its piston. The #4 articulating rod was bent approximately 45 degrees along the i-section of the rod and it was jammed against the cylinder skirt. The remains of the #3 rod were found inside the #5 cylinder with the wristpin end of the rod sticking out of the cylinder. #5 articulating rod had broken free from its piston at the piston wristpin. The wristpin for #5 was found still installed in the wristpin rod end.