Aviation Accident Summaries

Aviation Accident Summary DEN04LA110

Guernsey, WY, USA

Aircraft #1

N5667L

American AA-1

Analysis

According to the pilot, he just departed and was climbing. The pilot stated that the "engine started sputtering, and the tachometer went to 2200 rpm" and he was unable to maintain altitude. The pilot elected to land straight ahead due to "flatter" terrain. The airplane impacted a barbed wire fence and sage brush during the forced landing, causing substantial damage. The aviation routine weather report (METAR) reported the temperature as 77 degrees Fahrenheit (F) and the dewpoint was 54 degrees F. According to the Carburetor Icing Chart, these conditions are conducive for "serious icing at glide power." The contents of the airplane were weighed to calculate a weight and balance. The total weight of the airplane was calculated to be 1,580 pounds and the center of gravity was calculated to be 3 inches aft the most aft center of gravity limit.

Factual Information

On July 25, 2004, at 1030 mountain daylight time, an American AA-1, N5667L, piloted by a private pilot, was destroyed when it impacted terrain during a forced landing near Camp Guernsey Airport (7V6), Guernsey, Wyoming. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot sustained serious injuries. The cross-country flight was originating at the time of the accident and was en route to Oshkosh, Wisconsin. According to the accident report submitted by the pilot, he had just departed from runway 14 and was climbing. The pilot stated that the "engine started sputtering, and the tachometer went to 2200 rpm" and he was unable to maintain altitude. The pilot elected to land straight ahead due to "flatter" terrain. The airplane impacted a barbed wire fence and sage brush during the forced landing, separating the nose gear and both wings. The engine mounts separated on the upper left side of the firewall, the propeller separated at the hub and then firewall buckled. The both wings were crushed aft longitudinally and separated from the fuselage, the canopy was crushed and fragmented and the cabin area was crushed in on the left side. According to the FAA inspector who traveled to the scene, the contents of the airplane were weighed to calculate a weight and balance. The total weight of the airplane was calculated to be 1,580 pounds and the center of gravity was calculated to be 3 inches aft the most aft center of gravity limit. On November 4, 2004, the engine was examined, under the auspices of the NTSB, in Greeley, Colorado. The engine was checked for continuity and compression and the magnetos were checked for spark. During a compression check, conditions consistent with lower compression were present in the #1 cylinder. According to the engine logbook, the airplane underwent an annual inspection on July 14, 2004. During the inspection, the cylinders produced the following compression: #1 66/80, #2 70/80, #3 78/80, and #4 78/80. The FAA inspector stated these results are within acceptable tolerances. The Torrington aviation routine weather report (METAR), 22 miles south east of Guernsey reported the temperature as 77 degrees Fahrenheit (F) and the dewpoint was 54 degrees F. According to the Carburetor Icing Chart, these conditions are conducive for "serious icing at glide power."

Probable Cause and Findings

the pilot's inadequate use of carburetor heat which resulted in the formation of carburetor ice and loss of engine power. Factors contributing to the accident were weather conditions conducive for carburetor icing, and a lack of suitable terrain for a forced landing.

 

Source: NTSB Aviation Accident Database

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