On September 13, 1996, a Cessna 170B (registration N2916D) was involved in an aviation accident near Concord, CA. Investigators recorded the probable cause as: The pilot's failure to maintain directional control during the landing roll due to a sudden change in surface wind direction. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot lost directional control of a conventional gear airplane during the landing roll after surface winds shifted 90 degrees to the runway, creating a crosswind component.
What happened
The accident occurred during the landing phase of flight when the pilot was unable to maintain directional control of the aircraft. According to the report, the pilot experienced a loss of control while rolling out on the runway. The primary factor cited was a sudden change in wind conditions at the moment of touchdown.
Specifically, the surface winds shifted 90 degrees relative to the runway heading upon impact with the ground. This shift created a significant crosswind component that the pilot could not counteract effectively. Meteorological data indicated that a right crosswind component of 40 degrees existed at an airspeed of 13 knots at the time of the incident.
The investigation
Investigation into the mechanical aspects of the flight revealed no evidence of pre-impact mechanical failure or malfunction that would have contributed to the loss of control. The focus remained on the environmental conditions and the pilot's response to the wind shift during the critical landing roll phase.
Probable cause
The pilot's failure to maintain directional control during the landing roll due to a sudden change in surface wind direction.