Accident Sequence
While cruising at an altitude of 3,500 feet, the pilot encountered a partial loss of engine power. Attempts to restore full power were unsuccessful. The pilot radioed approach control, informed the controller of the situation, and requested radar vectors to the nearest airport for an emergency landing. Shortly thereafter, the engine ceased operating.
Emergency Landing
The pilot selected an emergency landing area and established an approach to a large pasture. During touchdown on the rough and uneven terrain, the right main landing gear separated from the aircraft.
Post-Accident Examination
Examination of the engine revealed that the engine-driven oil pump had failed. The pump had accumulated a total of 3,620 hours of service, with 1,682 hours since its last overhaul. Lycoming had issued a Service Bulletin instructing owners to replace sintered-iron impellers at 2,000 hours of engine service. However, an FAA Airworthiness Directive (AD) allowed operation up to 4,000 hours before replacing the impellers. The Propulsion Branch stated that a revised AD would be issued to correct the loopholes that led to this accident.