Incident Overview
A training flight in a conventional wheel (tail wheel-equipped) airplane resulted in a loss of control during a crosswind landing demonstration. The instructor pilot had taken over the controls after the pilot receiving instruction completed four stop-and-go landings on a runway aligned nearly directly with the wind. The instructor aimed to demonstrate a landing on a different runway where a crosswind of approximately 10 to 12 knots existed at a 90-degree angle to the runway.
Landing and Loss of Control
The instructor pilot executed a successful touchdown on the main landing gear wheels. However, as the airplane slowed and the tail began to lower to the runway surface, a gust of wind lifted the upwind wing. Despite the instructor's control inputs to counter the lift, the opposite wing struck the runway surface. The airplane then veered toward the upwind edge of the runway.
Departure from Runway
Before the instructor pilot could regain directional control, the airplane departed the right side of the runway and entered an area of soft terrain. The aircraft subsequently nosed over onto its back. According to the instructor pilot, no evidence of a flight control or rudder control malfunction was observed.