Casualties unknown

Aircraft Noses Over During Forced Landing on Snow-Covered Terrain (N3777P)

Thompson Falls, MT, US

On February 11, 1985, a Piper PA-18 (registration N3777P) was involved in an aviation accident near Thompson Falls, MT. Investigators recorded the probable cause as: Improper use of carburetor heat control and reduction of power during maneuvering, resulting in ice buildup in the carburetor, leading to engine failure and forced landing. 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 forced landing on snow-covered terrain resulted in the aircraft nosing over. The pilot reported improper use of carburetor heat and power reduction during maneuvering contributed to carburetor ice buildup.

Accident Overview

An aircraft conducting a deer survey flight experienced engine failure attributed to carburetor ice accumulation. The pilot executed a forced landing on terrain covered by approximately 20 inches of snow. During the landing, the aircraft nosed over.

Flight and Conditions

The flight was a deer survey mission. The pilot noted that icing conditions were 'perfect' for carburetor ice formation. The aircraft was operating in an environment conducive to ice buildup in the carburetor.

Carburetor Icing Factors

According to the pilot, improper use of the carburetor heat control contributed to the ice accumulation. Additionally, the pilot's reduction of power during maneuvering further facilitated ice buildup in the carburetor. These factors led to engine power loss, necessitating the forced landing.

Pilot's Recommendations

In the pilot's statement, he recommended under preventative measures that he should have been more aware of staying ahead of the engine's 'heat curve' to prevent carburetor icing. This reflects a recognition of the need for proactive carburetor heat management.

Probable cause

Improper use of carburetor heat control and reduction of power during maneuvering, resulting in ice buildup in the carburetor, leading to engine failure and forced landing.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X35679. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.