What happened
The aircraft was engaged in instructional flight operations, specifically practicing steep turns. During the maneuver, the engine lost oil pressure due to a crack in the propeller governor oil line, which ultimately caused the engine to seize. The instructor pilot assumed control of the aircraft and executed an emergency landing on a nearby road located within a sand pit area. Upon touchdown, the pilot was unable to steer the aircraft effectively through an 'S' turn on the road surface. Consequently, the aircraft collided with a sand hill.
The investigation
Examination of the engine components revealed that the area of the oil line where the crack occurred was heavily corroded. Additionally, the line was improperly attached to the engine, which contributed to the failure of the oil system and the subsequent loss of engine power.
Findings
The mechanical failure was directly linked to maintenance issues with the propeller governor oil line. The corrosion and improper attachment compromised the integrity of the oil line, leading to the loss of oil and engine seizure. The subsequent collision with the sand hill was a result of the pilot's inability to maintain directional control on the uneven road surface during the emergency landing.
Safety message
Regular inspection of critical engine lines for corrosion and proper attachment is essential to prevent in-flight engine failures. Pilots should also be prepared for potential loss of steering control during emergency landings on unprepared surfaces.