Piper PA31 N34WM accident near Point Thomson, Alaska

Probable cause

The pilot’s inadvertent descent below the published minimum descent altitude, while operating in flat light conditions, which resulted in controlled flight into terrain.

NTSB analysis

The pilot reported that while established on an RNAV GPS instrument approach to a remote airport, flat light conditions made it difficult to discern topographical features of the snow-covered terrain below. Prior to reaching the decision height altitude, the pilot said he looked outside for the runway environment, but the flat light condition caused him to spend more time looking outside and he became disorientated. When he looked back at the airplane’s instruments, he noticed the airplane was below the glide path and initiated a go-around maneuver; however, the airplane subsequently impacted snow-covered terrain. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for ANC23LA036 for the full record.