Primary finding
Probable cause
The pilot’s excessive braking during the landing roll, which resulted in a nose over. Contributing to the accident was the pilot’s lack of experience with the recently installed brakes and tundra tires.
Investigator assessment
Analysis narrative
The pilot reported that during the landing roll on the dry grass strip, he was making corrections with the brakes and the airplane nosed over, coming to rest inverted. The pilot assumed that he was “a bit too aggressive” with the brakes. The airplane sustained substantial damage to the right wing strut and the rudder. The pilot reported there were no preimpact mechanical malfunctions or failures with the airframe or the engine that would have precluded normal operation. The pilot further reported that the accident could have been prevented by “less or no excessive braking” during the landing roll. About 25 days (9.3 hours) before the accident, the airframe was modified with different landing gear legs, wheels, and brakes. Additionally, tundra tires were installed. The pilot reported that he thought he had become familiar with the recent modifications, but the nose over revealed that he probably wasn’t as familiar with the braking capability of the tundra tires as he thought he was. According to FAA Advisory Circular Systems and Equipment Guide for Certification of Part 23 Airplanes and Airships 23-17C, tundra tire installations on airplanes may reduce brake effectiveness during a braked landing and may result in an increased tendency to nose over during landing. The Airframes Alaska Installation Instructions and Instructions for Continued Airworthiness for Alaskan Bushwheel Tundra Tires ABI-Tire-ICA discusses post-installation testing and states: Always stay within the aircraft manufacturer’s limits. When your tundra tire installation is complete and inspected, and the brakes are safe, verify the function, ability, and adequacy of the whole system by conducting ground and air practice/comparison test runs at a safe area/altitude at your gross weight. Make note of any operational differences and include these in your flight planning, decision making, and operating techniques.