Amateur-built CARBON CUB CCK-1865 N625EX accident near Wasilla, Alaska

Probable cause

The failure of the tailwheel suspension assembly during landing due to preexisting fatigue fractures in the suspension system, which resulted in a loss of directional control.

NTSB analysis

The airline transport pilot was conducting a personal cross-country flight in the experimental amateur-built, tailwheel-equipped airplane. The pilot reported that, while landing on a turf and gravel airstrip, the airplane veered sharply left as the tailwheel touched down. Despite applying full right rudder and brake controls, the pilot was unable to correct the airplane's track, and the right wing and horizontal stabilizer impacted the ground. The pilot stated that, after the airplane stopped, he was unable to straighten the tailwheel with the rudder control inputs because the tailwheel was bent.

Postaccident metallurgical examination of the tailwheel suspension system revealed fractures within the welds of the assembly and a fatigue fracture at the bolt hole for mounting the tailwheel. The crack fracture surfaces exhibited orange and dark red corrosion, suggesting that the cracks were preexisting, and the fracture surfaces were consistent with overstress. The assembly also exhibited general twisting deformation, primarily as the result of deformation in the pivot bracket.

Text from the NTSB. Open the NTSB docket for ANC16LA059 for the full record.