Accident Overview
On December 26, 2023, at approximately 1221 mountain standard time, an experimental amateur-built Glasair SH2, registration N29TT, sustained substantial damage during a ground loop after landing. The accident occurred near Prescott, Arizona, and the pilot, the sole occupant, was uninjured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Sequence of Events
The pilot reported that after an uneventful wheel landing, he held the tail off the ground until the aircraft decelerated to about 30 mph. As soon as the tailwheel contacted the runway, the airplane swerved sharply to the right, ground looped, and came to rest at the edge of the runway.
The impact caused substantial damage to the forward left fuselage, which buckled and delaminated behind the firewall and just above the left main landing gear leg.
Postaccident Examination
Examination of the aircraft after the accident revealed that the tailwheel was jammed at a 45° angle to the left. The tailwheel assembly was equipped with a free-castering design that could be locked in the straight position for takeoff and landing. Locking was controlled by a lever in the cabin, connected via a cable to a spring-loaded locking arm in the tailwheel assembly. When activated, the locking arm dropped into a slot cut into the upper plate of the tailwheel trailing arm—a steel segment of about 90° arc welded to the tailwheel arms.
The pilot reported that he locked the tailwheel straight during takeoff using the cabin control and confirmed it was locked before landing. Postaccident inspection found both the cabin control and the locking arm in the locked position, yet the tailwheel was jammed at approximately 45° to the left.
Further examination showed that the locking arm and the associated plate slot were worn, and the locking spring had limited tension. This allowed the tailwheel to be moved out of the straight position with light force, then jammed over center as the locking arm dropped down against the outer edges of the locking plate.
Tailwheel System Details
Construction plans for the aircraft specified that the control cable should be routed directly from the locking arm to a phenolic guide in the vertical fin shear web. However, in the accident aircraft, the cable was routed from the locking arm down to a set of four cable ties mounted to the tailwheel strut.