N66JHVans Aircraft RV-6A · 2017

On December 18, 2008, about 1300 eastern standard time, an experimental amateur-built Spezio II, N66JH, was substantially damaged during a forced landing near Newville, Pennsylvania. The certificated airline transport pilot incurred minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed for the flight, between Tri-Cities Airport (CZG), Endicott, New York, and Carlisle Airport (N94), Carlisle, Pennsylvania. The personal flight was conducted under 14 Code of Federal Regulations Part 91.

According to the pilot, who was also the owner, he was delivering the airplane to a buyer in Georgia. After departing Endicott, the pilot planned on making a fuel stop in Hagerstown, Maryland. However, because he was more familiar with Carlisle, he diverted toward that airport. The pilot followed the Pennsylvania Turnpike toward the east, and with the airplane level about 1,000 feet above the ground (about 2,000 feet above mean sea level), the pilot added carburetor heat. The engine immediately began to run roughly, so the pilot attempted to add power, and the engine then quit. The airplane was over the turnpike at the time, and the pilot performed an engine-out approach to the eastbound lanes. As he flared the airplane for a landing, the pilot "suddenly" saw that he was approaching the back of a moving tractor trailer, and because the airplane's speed was slightly faster, it impacted the rear of the trailer before dropping 5 to 10 feet to the ground. As the airplane touched down, the landing gear collapsed, and the airplane nosed over a guard rail, which then caught part of the airplane's landing gear.

The pilot also noted that he had 4 to 5 gallons of fuel onboard the airplane at the time of the accident, and that the carburetor heat functioned properly during the engine run-up.

The airplane was powered by a Lycoming O-320-series engine.

Federal Aviation Administration (FAA) inspectors who examined the airplane after the accident did not note any preaccident mechanical anomalies and confirmed that 4 to 5 gallons of fuel were onboard. The inspectors subsequently attempted an engine run, during which, the engine started "easily and idled smooth and strong at 800 to 1,000 rpm." The engine was then shut down for about 3 minutes before being restarted and accelerated. Then, above 1,200 rpm, an "excessive" vibration developed, which was attributed to damage the propeller incurred during the accident sequence.

Weather, reported at an airport about 35 miles to the east, at 1256, included calm winds, 10 statute miles visibility, a broken cloud layer at 10,000 feet, temperature 3 degrees Celsius, dew point -2 degrees Celsius, and an altimeter setting of 30.30 inches Hg.

When the ambient temperature and dew point conditions were applied to the carburetor icing probability chart found in FAA Special Airworthiness Information Bulletin CE-09-05, the results indicated a probability of serious carburetor icing at cruise power.