NTSB Factual Report

On October 16, 2013, about 1730 eastern daylight time, an experimental, amateur-built Sonex, N68VF, operated by a private individual, was substantially damaged during a forced landing, following a total loss of engine power while on a go-around at Hiserts Airpark (3NY7), Palatine, New York. The sport pilot was not injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local flight that departed 3NY7 about 1700.

The pilot, who was an automobile mechanic, stated that prior to the accident flight, the four-cylinder Great Plains VW 2180 engine had been indicating low or no oil pressure. The pilot returned the engine to the manufacturer and subsequently received an overhauled engine as a replacement. He operated the overhauled engine for about 30 hours uneventfully. During the day prior to the accident, the pilot performed a routine 25-hour oil change and valve adjustment, with no anomalies noted.

During the accident flight, the pilot departed the grass airstrip with 8 gallons of gasoline and overflew it once without any difficulties. During the second approach, he intended to land, but was too high and performed a go-around. During the go-around, the pilot heard two "pops" and the engine lost all power. The propeller did not windmill and came to a complete stop. The airplane was at a low altitude and the pilot opted to land in a cornfield, rather than try to turn back to the runway. During the landing, the right main landing gear lodged in mud and the airplane nosed over.

Examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the right wing.

After the accident, under the direction of the FAA inspector, the pilot was able to rotate the propeller through and get compression on three cylinders, but then it locked on the fourth cylinder. The pilot moved the propeller backwards slightly and was then able to continue rotation. He subsequently started the engine and it ran without hesitation. The pilot then removed all of the cylinders and did not observe any preimpact mechanical malfunctions.

Schenectady County Airport (SCH), Schenectady, New York, was located about 20 miles southeast of the accident site. The recorded weather at SCH, at 1753, was: wind from 180 degrees at 7 knots; visibility 10 miles; overcast ceiling at 10,000 feet; temperature 16 degrees C; dew point 12 degrees C; altimeter 29.93 inches Hg.

According to an FAA carburetor icing envelope chart, the airplane was susceptible to serious icing at cruise power. However, the pilot reported that the engine was equipped with a flatslide aerobatic carburetor, which was not susceptible to carburetor ice due to the location in which it was mounted to the engine.

NTSB Probable Cause

A total loss of engine power for reasons that could not be determined because a test run and partial teardown of the engine did not reveal any anomalies.