Accident Overview
On August 12, 2020, at approximately 0800 mountain daylight time, a Stinson 108, registration N9726K, was substantially damaged during a landing accident near Glenwood Springs, Colorado. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 personal flight. Both occupants—the pilot and a flight instructor—were uninjured.
Landing Sequence
According to the pilot, upon touchdown, the tailwheel-equipped airplane immediately "lurched" to the right. The pilot attempted to correct, causing the airplane to initially veer left, but it subsequently veered right again and entered a ground loop. The left wing sustained substantial damage. The pilot noted that neither occupant was actuating the brakes at the time of the landing.
Postaccident Examination
A postaccident examination of the tailwheel assembly revealed that the locking pin (item #8 in a reference schematic) was sheared. This pin, when intact, locks the steering arm to the tailwheel fork assembly. With the pin sheared, the fork could rotate and pivot independently of the steering arm and rudder input, a condition known as free-castoring. This allowed the tailwheel to rotate freely more than 90°, contributing to the loss of directional control during the landing roll.
Aircraft and Damage
The Stinson 108 sustained substantial damage to the left wing structure. The aircraft was operated for personal purposes under Part 91 regulations. No other aircraft or property damage was reported.