What happened
A commercial pilot had recently purchased a conventional gear airplane from a Certified Flight Instructor (CFI) and requested a check-out flight. During the flight, the CFI supervised the owner through an initial landing.
Following the first landing, the CFI took control of the aircraft to demonstrate the performance characteristics of a three-point touchdown. During the rollout phase of this demonstration, the airplane began to veer to the right. The CFI attempted to correct the deviation by applying left rudder, but the aircraft continued its rightward roll. As a result, the airplane exited the side of the runway and entered a dirt area, where it nosed over.
The occupants were not injured during the incident.