Accident Overview
On August 24, 2022, at about 1118 Pacific daylight time, a Cessna 150H (registration N22507) experienced an engine malfunction shortly after takeoff from runway 20 at Nut Tree Airport (VCB) in Vacaville, California. The pilot and passenger sustained minor injuries. The airplane was substantially damaged and was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Report
The pilot stated that during the initial climb, at an altitude of approximately 200 to 250 feet above ground level, the engine began to sputter and the engine speed dropped to about 1,700 to 1,800 rpm. The pilot confirmed that the mixture and throttle were set to the takeoff positions, but the airplane was no longer climbing and altitude became difficult to maintain. The pilot then initiated a forced landing to an open field adjacent to the airport. During the landing roll, the airplane encountered uneven terrain and came to rest upright, resulting in substantial damage to the left wing and fuselage.
Postaccident Examination
Postaccident examination of the engine revealed it was partially attached to the engine mount. The carburetor had separated from the intake spider. The upper spark plugs and rocker box covers were removed, and the propeller was rotated by hand. Rotational continuity was established throughout the engine. Thumb compression was obtained on cylinders No. 1, 3, and 4, but no compression was obtained on cylinder No. 2, which was removed for further examination.
The No. 2 cylinder was found intact and undamaged. The exhaust and intake valve springs were intact and oil coated, as were the valve rocker arms. After removing the valve springs and keepers, the intake valve slid out of the valve guide freely, but the exhaust valve required significant force to remove. The exhaust valve stem exhibited carbon buildup along with the valve neck, and white deposits were observed around the rim of the valve. The valve seat also had carbon buildup. The intake valve stem showed carbon deposits on the neck and stem, with a slight amount on the rim, but no carbon buildup on the seat contact area.
Examination of the airframe and engine found no additional evidence of pre-existing mechanical malfunction that would have precluded normal operation.