Yellow Pine, ID, USA
N26HV
AVIAT AIRCRAFT INC A-1A
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.
HISTORY OF FLIGHTOn August 15, 2022, about 0630 mountain daylight time, an Aviat Aircraft Inc., A-1A, N26HV, was substantially damaged when it was involved in an accident near Yellow Pine, Idaho. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. A witness camping at Johnson Creek Airport (3U2), Yellow Pine, Idaho, reported that on the morning of the accident flight, he observed the accident airplane taxiing to runway 35. Due to the cool weather, he returned to his tent. He recalled hearing the airplane’s engine rpm rise, like the pilot was conducting a runup. The witness stated that he then heard the airplane take off, which was followed shortly after by a sound similar to a "door slamming shut". Between 1030 to 1045, he departed runway 35 and flew to Yellow Pine, before returning to and flying over 3U2. While overflying the north end of the airport, he observed the accident airplane in the creek near the departure end of runway 35. A witness provided video of the accident flight that showed the accident airplane departing from runway 35. The airplane became airborne within the first half of the runway, then about mid-field, the airplane made a climbing right turn over the trees and out of sight. The sound of the engine was heard throughout the video consistent with an engine at high rpm. A review of data retrieved from an onboard PED showed that at 0636:45 the accident airplane departed from runway 35, climbed to a GPS altitude of 5,067 ft mean sea level (msl), with an airspeed of about 60 kts (GPS speed) and entered a climbing turn to the northeast. The data showed that the airplane continued on a northeast heading, reaching a GPS altitude of about 5,193 ft msl, with an airspeed of about 47 kts. At 0637:11, the accident airplane made a climbing left turn to the northwest, at a GPS altitude of about 5,203 ft msl, with an airspeed of about 45 kts. The data showed that the airplane continued on a northwest heading, the airspeed slowed to about 36 kts, and the airplane descended to about 5,153 ft msl until contact was lost, as seen in figure 1. Figure 1: Google Earth overly of the final portion of the accident flight. PERSONNEL INFORMATIONThe pilot held a private pilot certificate that was issued about 9 months before the accident flight. At the time of the accident, he had accumulated about 170 total hours of flight experience, of which about 160 were in the accident airplane make and model. AIRCRAFT INFORMATIONOn July 25, 2022, an Airglas Inc., LC18H cargo pod was installed, changing the airplane’s empty weight from 1286.5 to 1357.30. The addition of the cargo pod changed the airplane’s useful load from 603.5 lbs to 532.7 lbs. Weight and balance values were calculated for the accident flight using the airplane’s weight and balance records and the weights of the two occupants. The weight of the airplane at the time of departure from 3U2 was estimated to be about 229 lbs over the maximum gross weight assuming 40 gallons of fuel, reported or measured occupant weights, and baggage. The CG was calculated using the passenger and seat locations in the most favorable position and was found to be outside the manufacturer’s tested/approved CG envelope. According to the airplane’s flight manual, the stalling speeds for the airplane with 0° flaps, 0° bank, is 51 mph (~44 kts), with 0° flaps, 30° bank, is 55 mph (~47 kts). The stalling speeds for the airplane with 30° flaps, 0° bank, is 45 mph (~39 kts), with 30° flaps, 30° bank, is 48 mph (~41 kts). AIRPORT INFORMATIONOn July 25, 2022, an Airglas Inc., LC18H cargo pod was installed, changing the airplane’s empty weight from 1286.5 to 1357.30. The addition of the cargo pod changed the airplane’s useful load from 603.5 lbs to 532.7 lbs. Weight and balance values were calculated for the accident flight using the airplane’s weight and balance records and the weights of the two occupants. The weight of the airplane at the time of departure from 3U2 was estimated to be about 229 lbs over the maximum gross weight assuming 40 gallons of fuel, reported or measured occupant weights, and baggage. The CG was calculated using the passenger and seat locations in the most favorable position and was found to be outside the manufacturer’s tested/approved CG envelope. According to the airplane’s flight manual, the stalling speeds for the airplane with 0° flaps, 0° bank, is 51 mph (~44 kts), with 0° flaps, 30° bank, is 55 mph (~47 kts). The stalling speeds for the airplane with 30° flaps, 0° bank, is 45 mph (~39 kts), with 30° flaps, 30° bank, is 48 mph (~41 kts). WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane impacted terrain about 265 ft northeast of the departure end of runway 35. The airplane impacted terrain in a nose-low attitude and came to rest upright in a creek, on a heading of about 116° magnetic, at an elevation of 4,892 ft msl. No visible ground scars or damaged vegetation were observed in the area near the wreckage. All major structural components of the airplane were located at the accident site. Figure 2: View of the accident site diagram. Flight control continuity was established from the cockpit to all primary flight controls. Numerous separations were noted within the flight control system with signatures consistent with overload separation or due to the recovery process. Postaccident examination of the recovered airframe and engine did not reveal evidence of any mechanical anomalies that would have precluded normal operation. ADDITIONAL INFORMATIONFederal Aviation Administration (FAA) publication H-8083-25A, Pilot's Handbook of Aeronautical Knowledge, stated that an aerodynamic stall results from a rapid decrease in lift caused by the separation of airflow from the wing's surface brought on by exceeding the critical angle of attack (AOA). AOA is defined as the acute angle between the chord line of the airfoil and the direction of the relative wind. An aerodynamic stall can occur when the airplane flies too slowly, or when higher wing loads are imposed due to maneuvers such as pull-ups or banked flight. MEDICAL AND PATHOLOGICAL INFORMATIONThe Valley County Coroner’s Office, McCall, Idaho, performed an autopsy of the pilot. The cause of death was multiple blunt force injuries. Toxicology testing performed at the FAA Forensic Sciences Laboratory found no drugs of abuse.
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.
Source: NTSB Aviation Accident Database
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