What happened
During an instructional flight, a student pilot was performing a series of full-stop wheel landings at the airport. Following the landing on the accident flight, the student pilot retarded the throttle to idle but began exhibiting erratic longitudinal control during the rollout phase.
In an attempt to maintain directional control, the instructor pilot applied left rudder and elevator control to bring the tailwheel onto the ground. Simultaneously, the student pilot depressed the brake pedals. This combination of inputs caused the aircraft to pitch forward onto its nose and subsequently overturn onto its back. The aircraft was equipped with dual puck Cleveland brakes, which were noted for their high sensitivity.
Findings
Prior to the flight in question, the instructor had specifically advised the student pilot that the brakes were extremely sensitive and instructed them to avoid using them excessively.