What happened
A commercial certificated pilot and six passengers were operating a scheduled VFR commuter flight between remote villages. Prior to departure, the pilot contacted the destination airport's village agent via radio and received a weather report indicating an 800-foot overcast ceiling and 5 miles of visibility. However, at the time of the accident, the weather at the scene featured an indefinite ceiling of approximately 500 feet and visibility of about 2 miles.
Following departure, the pilot maintained an altitude of approximately 450 feet above the ground while proceeding toward the destination. Approximately 10 minutes into the flight, the pilot reported that the horizon became obscured and the area ahead turned white; notably, there was no precipitation, but the ground and sky became indistinguishable. The pilot initiated a right turn toward the east, but approximately two seconds after beginning the maneuver, the airplane collided with snow-covered terrain. A passenger noted visibility was approximately 1 mile under gray skies.
The investigation
The aircraft was equipped with an avionics package from the FAA's Capstone Program, which includes GPS, ADS-B, and terrain information via a multifunction display (MFD). While the MFD offers a terrain mode with color-coded shading to indicate proximity to ground obstacles, this mode requires the pilot to manually enter barometric pressure data into the MFD menu, as the system does not automatically receive data from the aircraft's altimeter. The investigation found that the pilot had selected the moving map display at a five-mile scale rather than the terrain mode and had not entered any barometric pressure data into the MFD.
The pilot stated he did not observe any warning flags on the MFD. He also noted that he routinely used a personal GPS receiver mounted on the instrument panel glare shield because he was more familiar with it. Due to the typically flat terrain in Western Alaska, the pilot reported that he usually utilized the Capstone map mode with the GPS "go to" function rather than the specific terrain awareness mode.