What happened
The pilot, who had accumulated 85 hours of flight time, was conducting a private proficiency flight in a Cessna 170. The incident occurred during the final landing of the flight. The approach resulted in an apparently normal touchdown on the runway. During the subsequent landing roll, the aircraft began to swerve to the left. The pilot applied right rudder correction to counteract the deviation.
Despite the correction, the aircraft continued to turn to the right with an increasing rate of yaw. The pilot was unable to regain directional control or stop the turn. Consequently, the Cessna 170 departed the runway surface to the right side. As it left the paved area, the left main landing gear encountered soft fill dirt. The resistance from the soft ground caused the aircraft to pitch forward violently, resulting in a nose-over attitude.
The investigation
The physical examination of the aircraft confirmed that the left main gear had sunk into the unpaved surface adjacent to the runway. The structural damage was consistent with the nose-over event described by the pilot. No mechanical failures were reported prior to or during the landing roll that would explain the initial swerve.
Findings
The primary factor in this accident was the pilot's inability to maintain directional control during the landing roll. The sequence of events began with a leftward swerve, followed by an uncorrected right turn that led off the runway. The soft fill dirt on the shoulder of the runway played a critical role in the severity of the damage by causing the left gear to collapse and the aircraft to flip.
Safety message
Pilots should be aware that directional control can be lost during landing rolls due to various factors, including crosswinds or surface conditions. It is crucial to maintain active rudder input and monitor the aircraft's heading closely until a complete stop is achieved. Departing the runway onto soft surfaces can lead to catastrophic structural failure.