20050919020979A

(-23) The pilot was on a VFR flight from calaveras county airport (cpu) to ramona, CA (rnm). He had been in cruise flight at 7,500' MSL for approximately 40 minutes and had leaned the engine to "peak EGT" which he described as "aggressive leaning for economy". He elected to switch from main tank to right wing tip tank and the engine subsequently failed and would not restart despite the pilot switching back to main and turning the electric boost pump on. He reported that he did not enrichen the mixture and believes that may have been why the engine did not restart. He declared an emergency with ATC and diverted to Chowchilla, CA (2O6). The pilot determined he did not have sufficient altitude to reach 2O6 and made an emergency landing on a dirt road adjacent to a vineyard. The left wing tip impacted vineyard stakes causing outboard section of wing and tip tank to separate from aircraft. The aircraft slid approximately 150 feet further and came to rest on the dirt road with the nose 90 degrees counter clockwise from direction of ground track. Right wing was broken downward outboard of flap. Fuselage wrinkled forward of horizontal stabilizer. Engine mount and cowling damaged and bent in downward direction. One prop blade was curled back 8 inches from tip, other blade was curled back around engine cowling. A fuel stick with calibration marks found in the aircraft was used to obtain approximate fuel quantity. Less than 5 gallons, approximately, of fuel was found in the main tank with evidence of fuel leakage on ground under aircraft. Approximately 30 gallons was measured in the aux tank. No fuel was found in right wing tip tank. Left wing tip tank contained an undetermined quantity of fuel with substantial leakage of fuel found on ground around the tank, which was about 50 feet from the aircraft. Aircraft flight controls continuity was established. The pilot reported back pain and was taken to a local medical facility for a check up. The aircraft has modifications by addition of brittain wingtip tanks stac no. sa 4-915, accomplished 04-21-1974 and an aux tank in the rea of the cabin installed accomplished 07-11-1950. A Piper p/n 492068 fuel selector valve was installed at the time of the tip tank installation. During a subsequent interview with the pilot by phone, I asked him if he had a flight manual supplement or operating instructions for the fuel system. He stated that he did not, and was relying from verbal info given by the previous owner of the aircraft. The pilot produced a copy of a fuel receipt for the purchase of 40 gallons of 100LL avgas, dated 09-15-05 and stated that the aircraft had not been flown prior to date of accident.