Incident Overview
During cruise flight, the certified flight instructor (CFI) asked the student if he heard a knocking sound. The student confirmed hearing it. Both pilots then observed the oil pressure gauge reading zero. Simultaneously, the knocking increased, and the engine subsequently quit. The pilots executed an emergency landing.
Landing and Damage
On the landing rollout, the nose landing gear dug into soft dirt, causing the airplane to nose over.
Post-Accident Examination
An external examination of the engine revealed that the bottom of the fuselage, the firewall, and the rear of the engine were coated with oil. Further inspection showed that the oil filter had not been tightened or safety-wired to the engine.
Engine Logbook Review
Review of the engine logbook disclosed that an oil change had been completed the day prior to the accident.
Findings
The oil filter was found loose and not safety-wired, which allowed oil to escape during flight. This led to a loss of oil pressure, engine knocking, and eventual engine failure.