Accident Details
On August 16, 2012, at approximately 2154 central daylight time, a Piper PA-24-260 (registration N8546P) executed a forced landing on a rural road about 3 miles southwest of Holton, Kansas. The pilot and a pilot-rated passenger were seriously injured, while another passenger received minor injuries. The aircraft sustained substantial damage. The airplane was owned by N8546 PAPA, LLC of Tecumseh, Kansas, and operated by the pilot under 14 CFR Part 91 as a business flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The cross-country flight originated in Mitchell, South Dakota, around 2030, with an intended destination of Topeka, Kansas.
Events Leading to the Forced Landing
According to the pilot's accident report, after cruising at 7,500 feet mean sea level (msl), he initiated a 700-foot-per-minute descent approximately 37 miles from Topeka. At about 6,500 feet msl, he and his passengers detected a burning odor, and smoke began filling the cockpit. Oil pressure was lost, engine sounds changed, and the propeller oversped to high rpm. Shortly thereafter, the engine seized. The pilot declared an emergency with Kansas City air route traffic control center. He described an overcast sky with no moonlight, making the ground indistinguishable. Seeing automobile headlights, he aligned the airplane with them. He observed telephone poles and trees, attempted to skim the treetops, but a tree tore the right wing off mid-span, and the left wing separated when the airplane hit the road and nosed down into a ditch.
Post-Accident Examination
Two Federal Aviation Administration inspectors examined the airplane. The airworthiness inspector noted oil covering engine components in the aft engine compartment, with an oil-soaked right magneto hanging by spark plug wires. The magneto spacer bore exhibited nicks and scratches around its entire inner radius. A hole and crack were present in the engine case above the number 3 cylinder.
The engine, a Lycoming TI0-540-D4A5 (serial no. RL-6852-48), had been installed on May 5, 2005, following a major overhaul. The most recent annual inspection occurred on July 2, 2012, at a tachometer time of 8,545 hours, about 32 hours before the accident. The right magneto was replaced with a new unit on August 10, 2012, approximately 7 hours before the accident.
FAA inspectors interviewed the mechanic who replaced the magneto. He stated he could not recall whether he had torqued the magneto attachment nuts.