FlarePath

What happened

NTSB summary, verbatim

The pilot was conducting a commercial flight in his wheel/ski-equipped airplane with one passenger onboard in support of an arctic research project. He had overflown a potential landing site on a snow-and-ice-covered lake at a low altitude, and the area was determined to be unsuitable for landing. According to the passenger, after overflying the area the pilot initiated a left turn, toward the shoreline to return to their destination and subsequently impacted the ground. GPS data from the accident flight revealed that the airplane flew along the north shore of the lake at a GPS altitude of about 136 ft variable to 232 ft before initiating a left turn and descending until it impacted terrain. The passenger stated that the pilot had not voiced any concerns before the accident with regard to any preaccident mechanical failures or malfunctions that would have precluded normal operation and the plane sounded “good” during the accident flight. While the passenger reported a cabin and potential vegetation and terrain features visible in the left turn just before impact, it is likely that cloud conditions and snow-covered terrain present in the area resulted in flat light conditions, which would have hindered the pilot’s ability to perceive terrain features and closure rates.

Photographs

4the aircraft, and what the investigators found

Wreckage and site documentation · 4 photographs from the docket

Photographs are NTSB docket attachments — works of the US government, in the public domain. Captions are the Board’s own.

Probable cause

the Board's determination

The pilot’s controlled flight into flat snow-covered terrain in weather conditions that were conducive to flat light conditions.

Occurrence sequence

1 stepsNTSB coding · CICTT taxonomy

1 · Enroute
Controlled flight into terr/obj (CFIT)
defining event

Findings

1 causal · 1 contributing

CAUSE
Personnel issues › Action/decision › Info processing/decision › Decision making/judgment — Pilot
FACTOR
Environmental issues › Conditions/weather/phenomena › Light condition › Flat light — Contributed to outcome

NTSB analysis

from the final report

The pilot was conducting a commercial flight in his wheel/ski-equipped airplane with one passenger onboard in support of an arctic research project. He had overflown a potential landing site on a snow-and-ice-covered lake at a low altitude, and the area was determined to be unsuitable for landing. According to the passenger, after overflying the area the pilot initiated a left turn, toward the shoreline to return to their destination and subsequently impacted the ground. GPS data from the accident flight revealed that the airplane flew along the north shore of the lake at a GPS altitude of about 136 ft variable to 232 ft before initiating a left turn and descending until it impacted terrain. The passenger stated that the pilot had not voiced any concerns before the accident with regard to any preaccident mechanical failures or malfunctions that would have precluded normal operation and the plane sounded “good” during the accident flight. While the passenger reported a cabin and potential vegetation and terrain features visible in the left turn just before impact, it is likely that cloud conditions and snow-covered terrain present in the area resulted in flat light conditions, which would have hindered the pilot’s ability to perceive terrain features and closure rates.