Incident Overview
A pilot reported that during the flight, the oil pressure gauge began fluctuating. As a precaution, the pilot landed the airplane on a road to examine the engine. After landing, the pilot conducted a walk-around inspection, checking for leaks, oil level, and security of the oil cap. No anomalies were found.
Takeoff and Encounter
The pilot proceeded to take off from the road. During the takeoff roll, while the airplane was gaining airspeed in ground effect, the departure path passed over a terrain depression and into a downsloping bowl. The airplane encountered a sudden sink/down flow of air and lost approximately 10–15 feet of altitude. The pilot attempted to turn toward lower terrain while maintaining airspeed, but the sink/down flow continued.
Maneuvering and Landing
Unable to reach a meadow for landing, the pilot turned the airplane into sloping terrain to minimize impact energy. During the impact, the airplane sustained damage to both wings, the fuselage, and the empennage.
Pilot Remarks
The pilot reported that there were no mechanical failures or malfunctions. The fluctuating oil pressure gauge was considered likely due to the sending unit location on the engine and associated vibration or a loose ground connection.