Casualties unknown

Pilot Loses Situational Awareness, Strikes Terrain During Night IFR Departure in Snowstorm (N2654M)

Mammoth Lakes, CA, US

On January 5, 1992, a Cessna 421C (registration N2654M) operated by Frank Gearhart was involved in an aviation accident near Mammoth Lakes, CA. Investigators recorded the probable cause as: The pilot failed to maintain terrain clearance and became lost and disoriented. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-07-04Data APIEditorial standards

A commercial pilot and five passengers departed early from an uncontrolled mountainous airport due to an impending snowstorm. While climbing toward a VOR in IMC and attempting to open an IFR flight plan, the pilot failed to maintain terrain clearance, became lost and disoriented, and struck trees and snow-covered terrain.

Flight Details

The flight involved a certificated commercial pilot and five passengers. The departure occurred one day earlier than originally planned due to the impending arrival of a snow storm. The flight originated from an uncontrolled airport located in mountainous terrain and was a night, cross-country flight. Instrument meteorological conditions (IMC) prevailed at the time.

Sequence of Events

Prior to departure, the pilot received an IFR clearance with a void time from an Air Route Traffic Control Center (ARTCC). After takeoff, the pilot began climbing toward a VOR located approximately 27 miles southeast of the departure airport. While attempting to contact the ARTCC to open the instrument flight plan, the pilot failed to maintain terrain clearance and became lost and disoriented.

The airplane subsequently struck trees and snow-covered terrain at an elevation of 10,200 feet MSL. The impact point was approximately 7 nautical miles and about 22 degrees to the right of the intended course.

Findings

The investigation determined that the pilot failed to maintain terrain clearance and became lost and disoriented during the climb in instrument conditions.

Probable cause

The pilot failed to maintain terrain clearance and became lost and disoriented.

Frequently asked questions

What happened in the 5 Jan 1992 Cessna 421C accident near Mammoth Lakes, CA?

A commercial pilot and five passengers departed early from an uncontrolled mountainous airport due to an impending snowstorm. While climbing toward a VOR in IMC and attempting to open an IFR flight plan, the pilot failed to maintain terrain clearance, became lost and disoriented, and struck trees and snow-covered…

What aircraft was involved and where did it happen?

The accident on 5 Jan 1992 involved a Cessna 421C, registration N2654M, operated by Frank Gearhart, at Mammoth Lakes, CA.

What was the probable cause of the accident?

The pilot failed to maintain terrain clearance and became lost and disoriented.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X13996. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.