What happened
While performing an approach to land at a private airstrip, an agricultural airplane experienced a sudden loss of control. According to the pilot, the control stick locking device, known as a gust lock, unexpectedly fell into the locked position, which resulted in the control stick jamming.
At a very low altitude, the aircraft's left wing made contact with the ground. This impact caused the airplane to cartwheel, an event that resulted in the separation of both wings from the fuselage. The pilot was not injured.
The investigation
Investigators conducted an examination of the aircraft to identify any mechanical or structural failures. No structural or mechanical anomalies were observed during the inspection of the airplane.
Per the aircraft manufacturer's design, engaging the gust lock requires rotating the assembly by hand from beneath the instrument panel to a position above the control stick, followed by lowering the barrel portion of the lock onto the stick. However, during the investigation, the barrel portion of the contact for the control lock could not be located. Furthermore, no evidence of contact between the control stick and the gust lock barrel was found on the control stick itself.