Incident Overview
A flight instructor, acting as pilot-in-command during a cross-country flight in a student pilot's airplane, was accompanied by the student and three passengers. Before departure, the instructor checked the engine oil level, finding it at 9 quarts, and noted that the oil on the dipstick appeared clean.
In-Flight Events
During cruise flight, the low oil pressure warning light began flickering, and the oil pressure indication dropped. The instructor discussed the situation with the student pilot, decided to continue the flight, and monitored other engine gauges while noting that the engine continued to run smoothly.
Approximately 20 minutes later, a slight clattering noise emanated from the engine. The instructor then elected to divert to a nearby airport. Shortly after, a loud bang was heard, and the engine seized completely.
Forced Landing and Impact
A forced landing was executed to a small pasture. During the landing, the airplane collided with a fence and trees.
Post-Accident Examination
Inspection of the aircraft revealed no oil on the top of the cowling or windshield. However, oil was present on the bottom of the cowling and streaked along the bottom of the fuselage. Examination of the engine disclosed evidence of an internal catastrophic failure consistent with a lack of sufficient lubrication.