ERA18FA150 · Piper PA28 140

The commercial pilot completed a normal preflight inspection and engine run-up and received an instrument flight rules clearance from air traffic control to depart from the uncontrolled airport, where fog, low visibility, and clouds were present. Shortly after takeoff, the airplane entered the clouds and fog, climbed on the departure runway heading, and turned right, consistent with the clearance provided; however, the airplane continued the right turn, flying a 360° circle. During the circle, the airplane rapidly descended to about 60 ft above ground level (agl) then climbed to about 600 ft agl. The last radar data point showed the airplane at 356 ft agl, flying at 42 knots groundspeed. There were no communications received from the pilot during the flight. The wreckage was located in an open field about 1/4 mile from the last radar data point.

A postaccident examination of the airplane and the airplane's primary vacuum system did not reveal any anomalies consistent with a preimpact failure or malfunction. The airplane was equipped with a standby vacuum system and an electrically-powered attitude indicator, and the investigation found no anomalies with these components. Due to impact and fire damage, the investigation could not determine whether the standby vacuum system was activated by the pilot.

The restricted visibility, maneuvering, and workload associated with the initial post-takeoff phase of flight provided conditions conducive to the development of spatial disorientation, and the changes in the airplane's altitude, heading, and speed depicted on radar are consistent with the known effects of spatial disorientation. It is likely that the pilot experienced spatial disorientation during the climbing departure turn, which resulted in an exceedance of the airplane's critical angle of attack, an aerodynamic stall, and a subsequent impact with terrain.

Verbatim NTSB analysis and probable cause from the NTSB dataset