As The Airplane Reached Mid-Field, It Made A Climbing Right Turn Over The Trees And Disappeared From The Camera View

Location: Yellow Pine, Idaho Accident Number: WPR22FA304
Date & Time: August 15, 2022, 06:30 Local Registration: N26HV
Aircraft: Aviat Aircraft Inc A-1A Aircraft Damage: Substantial
Defining Event: Loss of control in flight Injuries: 2 Fatal
Flight Conducted Under: Part 91: General aviation - Personal

Analysis: A video of the accident flight showed the airplane departed runway 35 and became airborne within the first half of the runway. As the airplane reached mid-field, it made a climbing right turn over the trees and disappeared from the camera view. The airplane impacted terrain shortly thereafter. The sound of the engine running can be heard throughout the video.

Postaccident examination of the airplane revealed no evidence of any preexisting mechanical malfunction that would have precluded normal operation. A review of weight and balance information showed that, at the time of departure, the airplane was likely about 229 lbs over its maximum gross weight. Additionally, although the loading and seating positions could not be verified, an estimated calculation placed the airplane’s center of gravity (CG) outside of the manufacturer’s tested/approved CG envelope.

Flight track data retrieved from a personal electronic device (PED), showed that the airplane’s speed decreased to 45 knots during the takeoff climb. The airplane's increased weight would have resulted in an increased stall speed. Given the increased airplane weight and the slow airspeed during the takeoff climb, it is likely that the pilot exceeded the airplane’s critical angle of attack, which resulted in an aerodynamic stall and subsequent impact with terrain. 

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- The pilot's failure to maintain adequate airspeed during an initial climb, which resulted in the exceedance of the critical angle of attack, subsequent aerodynamic stall, and impact with terrain. Contributing was the pilot’s decision to operate the airplane above its maximum gross weight.

FMI: www.ntsb.gov