Casualties unknown

Engine Roughness and Stall During Low-Altitude Maneuvering (N3992P)

Jordan Valley, OR, US

On July 25, 1999, a Piper PA-18A-150 (registration N3992P) was involved in an aviation accident near Jordan Valley, OR. Investigators recorded the probable cause as: The pilot's inadvertent stall/mush of the aircraft while attempting a forced landing due to partial power loss of the engine. Factors include carburetor icing conditions and the pilot's improper use of carburetor heat. 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

While maneuvering at about 100 ft AGL, a pilot encountered engine roughness after adding power to climb over terrain. Application of carburetor heat caused further power loss. An emergency landing in a clearing failed when the aircraft stalled at approximately 20 ft AGL.

Accident Summary

During maneuvering at approximately 100 feet above ground level (AGL), the pilot added power to out-climb rising terrain. Shortly after the power application, the engine began to run rough, prompting the pilot to apply carburetor heat. The use of carburetor heat resulted in a further loss of power, leading the pilot to return the carburetor heat to the off position. He then attempted to remedy the suspected carburetor icing by cycling the carburetor heat on and off.

Sequence of Events

When these actions did not restore the engine to full power, the pilot decided to attempt an emergency landing in a nearby clearing. While on final approach to the clearing, still approximately 20 feet AGL, the aircraft stalled/mushed into the terrain.

Carburetor Icing Conditions

According to the DOT/FAA Carburetor Icing Probability Chart, carburetor icing could be expected at the temperature and dew point present at the accident site at the time of the event.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X19384. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.