The airline transport pilot was departing from a remote unimproved airstrip in Fairbanks, Alaska.
He stated that, as he initiated the takeoff, everything seemed normal. About 300′ into the takeoff roll, the Helio H295 veered sharply left, exited the airstrip, and hit brush and trees, which resulted in substantial damage to the fuselage and left horizontal stabilator.
A post-accident examination of the airplane revealed that the tailwheel had separated from its attachment point and folded underneath the empennage.
Visual and magnified optical examinations revealed deformation and fracture patterns consistent with an overstress failure.
Although fatigue cracks were observed in the fractured left arm of the tailwheel A-frame, they were relatively small and would not likely have caused a failure without abnormal loading.
Additionally, the fractures in the left arm initiated not only at the fatigue cracks but also at locations away from the fatigue cracks, consistent with an overstress fracture.
It is likely that the tailwheel A-frame fractured due to excessive side loads on the frame, which led to the tailwheel separating and the subsequent loss of control.
Probable cause: Excessive side loads imposed on the tailwheel A-frame during the takeoff roll, which resulted in a separation of the tailwheel and the subsequent loss of directional control.
NTSB Identification: ANC16LA067
This September 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.