On October 31, 1999, a Cessna 170A (registration N9063A) was involved in an aviation accident near EL Mirage, CA. Investigators recorded the probable cause as: The pilot's loss of directional control during rollout on an unprepared surface. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot conducted a precautionary landing on a dry lakebed due to perceived engine roughness. Directional control was lost during rollout, resulting in a ground loop despite no actual mechanical failure.
What happened
The pilot was operating a personal flight when he noticed the engine running roughly. To assess the situation safely, he chose to perform a precautionary landing on a smooth, dry lakebed. During the rollout phase of the landing, the aircraft lost directional control and ground looped. The wind conditions at the time were light and variable. After the incident, the pilot reported that no mechanical problems or malfunctions had occurred during the flight.
Findings
The loss of directional control was attributed to the surface conditions and rollout dynamics rather than a mechanical failure. The pilot's decision to land on an unprepared surface contributed to the outcome.
Probable cause
The pilot's loss of directional control during rollout on an unprepared surface.