Casualties unknown

Mountain Pass Whiteout Leads to Tree Impact (N212M)

Sula, MT, US

On June 14, 1992, a Beech K35 (registration N212M) operated by Mcchristy, John C. was involved in an aviation accident near Sula, MT. Investigators recorded the probable cause as: The pilot's failure to maintain visual reference with the terrain while flying through a mountain pass in whiteout conditions, which resulted in controlled flight into terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

A pilot flying through a mountain pass encountered whiteout conditions and entered instrument meteorological conditions, resulting in a collision with trees while attempting to reverse course.

What happened

The flight was proceeding under visual flight rules through a mountainous region. While navigating a mountain pass at an altitude of approximately 1,000 to 1,200 feet above ground level, the aircraft encountered severe weather conditions known as a whiteout. This phenomenon caused the pilot to lose visual reference with the horizon and terrain, effectively placing the airplane into instrument meteorological conditions.

Upon realizing the loss of situational awareness, the pilot immediately initiated a climbing left turn in an effort to reverse the course and escape the hazardous environment. However, during the execution of this maneuver, the aircraft struck trees located on the wall of the valley.

Probable cause

The pilot's failure to maintain visual reference with the terrain while flying through a mountain pass in whiteout conditions, which resulted in controlled flight into terrain.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X15003. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.