Heber City, UT, USA
N134US
Clarke YAK 3UR 2000
When the airplane turned downwind, the engine lost power. The pilot attempted to restart the engine, and it surged suddenly. The torque caused the airplane to roll inverted. The pilot managed to roll the airplane upright, but was unable to restart the engine and he made a forced landing on airport property, striking the ground hard and substantially damaging the airplane. Examination and tesing of the carburetor revealed the enrichment cover was leaking, and there was "a substantial leak" at one of the vapor vent ports. One of the vapor vent floats was not functioning. When the vapor vent port was plugged, the carburetor tested between 7 and 22 pounds per hour above the rich limit.
On July 9, 2005, at 0915 mountain daylight time, a YAK 3UR 2000, N134US, piloted by a airline transport pilot, sustained substantial damage when it impacted terrain during a forced landing near Heber City Airport, Heber City, Utah. Visual meteorological conditions prevailed at the time of the accident. The local personal flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot and passenger sustained minor injuries. The flight originated in Caldwell, Idaho, and was destined for Heber City, Utah. In a telephone interview, the pilot said that when he turned downwind, the engine lost power. When he attempted to restart the engine, it surged and the torque caused the airplane to roll inverted. The pilot managed to roll the airplane upright, but was unable to restart the engine. He said he "planted" the airplane on the ground. The airplane "bounced ten times" and came to rest 200 to 250 yards from the initial impact point. The engine was torn away from the fuselage. The carburetor was examined at Precision Engines Corporation in Everett, Washington, and a report issued. The report noted that the enrichment cover was leaking, and there was "a substantial leak" at one of the vapor vent ports. One of the vapor vent floats "does not appear to be functioning correctly," the report said. The vapor vent port was plugged and the carburetor was functionally tested. The carburetor tested between 7 and 22 pounds per hour above the rich limit on test points 1 through 16. All other test points were within limits, as was the automatic mixture control.
loss of engine power due to a leaking carburetor and an inoperative float, and the pilot's failure to maintain aircraft control during the restart attempt. Contributing factors were the sudden engine power surge during the attempted restart, and unsuitable terrain on which to make a forced landing.
Source: NTSB Aviation Accident Database
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