CEN09LA105

Following a three-hour preheat, utilizing a Tanis heater, the flight departed and entered a cruise condition at 10,500 feet. While in cruise flight, the pilot noted a loss of oil pressure and reversed course to head back to the airport. While en route to the airport the engine began to run rough and eventually stopped running. During the forced landing, the right wing impacted a fence post resulting in substantial damage. Examination of the engine revealed a large hole just above the number two cylinder orifice, in addition to mechanical damage throughout the engine. The number one and two connecting rods, bearings, and journals all exhibited extensive mechanical and lubrication damage consistent with oil starvation. An examination of the remaining engine components revealed no anomalies. The reason for the loss of oil pressure and oil starvation in the engine was not determined.

On December 28, 2008, approximately 0830 mountain standard time, N3064M a single engine Piper PA-28R-201T airplane was substantially damaged during a forced landing to a field near Santa Fe Municipal Airport (KSAF), Santa Fe, New Mexico. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91 without a flight plan. The pilot and his three passengers were not injured. The cross-country flight departed KSAF approximately 0815 and was en route Scottsdale Airport (KSDL), Scottsdale, Arizona. According to the Pilot Operator Aircraft Accident Report Form submitted by the pilot, the airplane had been preheated for at least three hours, utilizing a Tanis heater, prior to departure. The airplane was at a cruise altitude of 10,500 feet when the pilot noticed a drop in oil pressure. The pilot decided to return to KSAF. While en route to KSAF, the engine began running rough "which progressed until it failed completely." During the forced landing to a field, the right wing contacted a fence post. The leading edge of the wing was crushed aft and wrinkled, the spar and several ribs were damaged, and the fuel tank was ruptured. Weather at KSAF was reported as winds calm, 10 miles visibility, clear skies, temperature minus 8 degrees Celsius (C), dew point minus 16 degrees C, and an altimeter setting of 30.32 inches of mercury. Temperatures three hours prior to the accident were recorded as low as minus 12 degrees C. The engine was removed from the airframe and shipped to Teledyne Continental Motors, in Mobile, Alabama, for further examination. Investigators from Teledyne Continental Motors and the National Transportation Safety Board examined the engine on April 30, 2009. During the examination, a large hole was noted on the left side of the crank case half, in-line, and above the orifice for the number two cylinder. Further examination revealed mechanical damage on the number one, three, and four bays of each crank case half. Mechanical damage was also noted on the rearward three camshaft lobes, the counterweight assembly on the crankshaft, and the cylinder skirt on the number one, two, three, and four cylinders. The number one and number two connecting rods, and connecting rod bearings were broken, fractured, and fragmented. These pieces exhibited thermal and mechanical damage. The bearing fragments exhibited lubrication and thermal distress. Examination of the crankshaft revealed mechanical damage, lubrication distress, and thermal discoloration to the number one and number two connecting rod journals. The remaining components in the engine exhibited normal operating and lubrication signatures. All oil galleys and passages were clear and free of blockages or contamination. No further anomalies were noted.