Woodland, WA, USA
N106AL
OTTERBACK Lightning
The pilot reported that after an uneventful flight in an experimental airplane he set up for landing. At about 1,200 feet he reduced the throttle to idle, turned on the carburetor heat, and entered the traffic pattern. After turning final, when the pilot began to reach for the throttle, the propeller stopped spinning. The engine had lost complete power, with no engine roughness or abnormal noises. Since the airplane was about 50 ft above the ground, the pilot continued to land onto the runway. The airplane bounced and when it touched back down, the airplane departed the left side of the runway. The pilot redirected the airplane back toward the runway surface, but the nose gear collapsed on the rough grass. The nearest weather reporting station indicated temperature 13°C, dewpoint 4°C. Review of the Carburetor Icing Probability Chart revealed that, given the temperature and dewpoint, the conditions were on the line between serious icing at glide power and serious icing at cruise power. During a telephone conversation the pilot reported that the carburetor heat system takes hot air from near the muffler to keep the carburetor from icing up. It is likely that the carburetor accumulated ice while in cruise flight and the carburetor heat, when applied when the pilot reduced the throttle to idle, was not sufficient to remove the carburetor ice which resulted in a loss of engine power.
On May 1, 2019, about 1030 Pacific daylight time, an experimental, amateur-built Lightning airplane, N106AL, was substantially damaged when it was involved in an accident at the Woodland State Airport (W27), Woodland, Washington. The pilot and passenger were not injured. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. The pilot reported that after an uneventful flight he entered the traffic pattern at about 1,200 ft above ground level (agl), reduced power to idle and turned on the carburetor heat. After turning to final approach, the engine lost complete power, with no engine roughness or abnormal noises. Since the airplane was about 50 ft above the ground, the pilot continued to land onto the runway. The airplane bounced and when it touched back down, the airplane departed the left side of the runway. The pilot redirected the airplane back toward the runway surface, but the nose gear collapsed on the rough grass substantially damaging the lower fuselage and engine mounts. The airplane is equipped with an experimental Jabiru 3300 engine. During a telephone conversation the pilot reported that the carburetor heat system takes hot air from near the muffler to keep the carburetor from icing. However, when the airplane is at idle for an extended period, the engine and exhaust cool, and the air being supplied to the carburetor is not as hot, making the carburetor susceptible to carburetor ice, particularly in severe icing conditions. The 0953 automated weather observation at the Scappoose Industrial Airpark (SBP), Scappoose, Oregon, located about 9 miles southwest of the accident site, included calm wind, visibility 10 statute miles, clear skies, temperature 13°C, dewpoint 4°C, and an altimeter setting of 30.11 inches of mercury. Review of the Carburetor Icing Probability Chart in the Federal Aviation Administration Special Airworthiness Information Bulletin for Carburetor Ice Prevention revealed that, given temperature and dewpoint, the conditions were on the line between serious carburetor icing at glide power and serious carburetor icing at cruise power.
A complete loss of engine power due to carburetor icing.
Source: NTSB Aviation Accident Database
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