Accident Details
On September 19, 2010, at approximately 1325 eastern daylight time, a Navion G, registration N2448T, was substantially damaged during a forced landing to a field following a loss of engine power in cruise flight near Dublin, Georgia. The flight, operated by an airline transport pilot (ATP), was conducted under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the planned flight to Cannon Creek Airpark (15FL), Lake City, Florida. The flight originated from Evansville Regional Airport (EVV), Evansville, Indiana.
According to the pilot, the airplane was in cruise flight at 7,000 feet mean sea level when the engine began to run rough and the oil pressure decreased. The pilot informed air traffic control, and the controller provided a vector for the nearest suitable airport, W H "Bud" Barron Airport (DBN), Dublin, Georgia. However, the pilot was unable to reach the airport and performed a gear-up forced landing to a field about 6 miles southeast of DBN. During the landing, the airplane struck a ditch and came to rest upright, resulting in substantial damage to the empennage.
Aircraft and Pilot Information
The pilot, age 78, held an ATP certificate with type ratings in multiple transport category airplanes and also held a mechanic certificate. His most recent Federal Aviation Administration third-class medical certificate was issued on July 1, 2009. He reported a total flight experience of 18,763 hours, with 720 hours in the same make and model as the accident airplane.
The airplane was equipped with a Teledyne Continental Motors IO-520-BA, 285-horsepower engine. The most recent annual inspection was completed on April 8, 2010, at which time the engine had accumulated about 469 hours since major overhaul. The airplane had flown about 25 hours from that inspection until the accident. The pilot stated that sometime after the annual inspection but before a recent trip to Pennsylvania, he changed the oil but could not remember the date and forgot to record the oil change in the aircraft logbooks.
Post-Accident Examination
An FAA inspector noted that the No. 5 cylinder was cracked at the base. No oil was observed on the dipstick, but significant amounts of oil were present on the engine cowling. When the engine was recovered from the field, an oil drain tube remained attached to the oil quick-release drain plug, and oil was leaking down the side of the tube.
The engine underwent a teardown examination at the manufacturer's facility under the supervision of an NTSB investigator. The examination revealed several cracks in the engine case at the No. 5 cylinder base. The case was pushed out, consistent with impact from a loose connecting rod. Disassembly showed evidence of thermal distress on the crankshaft at the No. 4 and No. 5 connecting rods and evidence of lack of lubrication. Less than 2 quarts of oil were recovered from the 12-quart-capacity engine. The No. 5 connecting rod was fractured at the crankshaft attachment points, and the attachment fittings were loose in the oil pan.