Accident Overview
A certificated flight instructor was providing instruction to the private pilot and new owner of a tundra tire-equipped tailwheel airplane. The flight instructor was seated in the rear seat, while the pilot/owner occupied the front. The pilot/owner had accumulated 66 total flight hours, including 14 hours as pilot-in-command and 0.5 hours in the accident airplane.
Accident Details
Approximately five minutes after takeoff, the student pilot was performing a landing on an asphalt runway that had areas of ice along the edges. During the landing roll, the airplane began to drift to the right. The instructor applied left rudder input, but the airplane departed the right side of the runway into an area of snow. The airplane then nosed over, sustaining damage to the propeller, fuselage, and wing lift struts.
Post-Accident Observations
Prior to the flight, the right master brake cylinder, installed in the front seat area, had been serviced. Additionally, a heater hose was installed in the cabin to direct heat into the rear seat area. The instructor reported that the airplane's right brake felt as if it was locked, which she suggested may have been due to overfilling the brake reservoir and subsequent heating of the brake cylinder by the heater. The instructor cited two previous NTSB reports of brake cylinder locking after extended flight with a heater hose blowing hot air on a brake reservoir. Review of those reports indicated that the earlier incidents involved aircraft where a heater hose was directed onto the master brake cylinders after the cylinders had been serviced. One of those incidents occurred after 1.5 hours of flight time before landing, and the other after 3 hours. The accident airplane's brake system was not examined postaccident.