Air Tractor AT802 N80166 accident near Birch Creek, Alaska

Probable cause

A loss of control for undetermined reasons while on the surface of the water during scoop operations in support of wildland firefighting operations.

NTSB analysis

The mission-specific modified airplane was used to support wildland firefighting operations. It was equipped with amphibious floats that routed water through a dual scoop system to a hopper located in the airplane. The scoops could be manually deployed by a switch located on the control stick.

According to the pilot, on the 28th scoop of the day, he touched down on the surface of the water and deployed the scoops to begin filling the airplane’s hopper when the airplane veered to the right. In an effort to correct for the veer, he released the scoop switch and applied left rudder to no avail. He retarded the throttle and applied reverse thrust as the airplane began to impact trees located on the lake’s shoreline. The airplane came to rest upright in a marshy area on the lake’s shoreline sustaining substantial damage to the right wing.

A series of detailed examinations of the airplane, including its water scoop system, revealed no preaccident mechanical failures or malfunctions that would have precluded normal operations.

Text from the NTSB. Open the NTSB docket for ANC20LA069 for the full record.