Aviation Accident Summaries

Aviation Accident Summary SEA99LA130

JORDAN VALLEY, OR, USA

Aircraft #1

N3992P

Piper PA-18A-150

Analysis

While maneuvering at approximately 100 feet agl, the pilot applied power to out-climb rising terrain. Just after he applied power, the engine started to run rough, and the pilot applied carburetor heat. The application of carburetor heat resulted in a further loss of power, so the pilot returned the carburetor heat to the off position. He then used a combination of on-off-on settings in an attempt to remedy the suspected carburetor icing. Because his actions did not result in the engine returning to full power, he elected to attempt an emergency landing in a nearby clearing. While on final approach to the clearing, and still approximately 20 feet agl, the aircraft stalled/mushed into the terrain. According to the DOT/FAA Carburetor Icing Probability Chart, carburetor icing could be expected at the temperature/dew point present at the accident site at the time of the subject event.

Factual Information

On July 25, 1999, approximately 0630 Pacific daylight time, a Piper PA-18A-150, N3992P, was damaged during a hard landing on rough terrain about 15 miles northwest of Jordan Valley, Oregon. The private pilot and his passenger were not injured. The aircraft, which was owned and operated by a friend of the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight departed a private airstrip located near Rome, Oregon, about 30 minutes prior to the accident. No flight plan had been filed and there was no report of an ELT activation. The pilot stated that, while cruising at approximately 100 feet above the ground (agl), power was applied to out-climb rising terrain. Just after the power application, the engine started to run rough, so the pilot applied carburetor heat. The application of carburetor heat resulted in a further loss of power, so the pilot returned the carburetor heat to the off position. He then used a combination of on-off-on settings in an attempt to remedy the suspected carburetor icing. Because his actions did not result in the engine returning to full power, he elected to attempt an emergency landing in a nearby clearing. While on final approach to the clearing, and still about 20 feet above the ground, the aircraft stalled/mushed into the terrain. The closest weather information available to the accident site was the Boise Air Terminal, Boise, Idaho, 0656 METAR observation. The temperature was 16 degrees C and the dewpoint was 7 degrees C. According to the DOT/FAA Carburetor Icing Probability Chart, carburetor icing could be expected at glide and cruise power under these temperature/dewpoint conditions.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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