NTSB Factual Report

On July 3, 2005, at 0835 eastern daylight time, an Aeronca 11CC, N4337E, was substantially damaged when it impacted a tree and terrain after takeoff from a private grass strip in Charlotte, Vermont. The certificated private pilot/owner was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, conducted under 14 CFR Part 91.

According to a Federal Aviation Administration (FAA) aviation safety inspector, the airplane had not flown since November 2004. The pilot/owner pushed the airplane out of its hangar on the morning of the accident, washed it, then departed for the local flight.

In a telephone interview, a pilot-rated witness stated that he watched the accident flight from a vantage point that was at an elevation above the grass strip, and the crash site. He explained that he was unloading an automobile with a friend, when he heard the sound of an airplane engine start.

Because of his proximity to Lake Champlain, and other smaller lakes, the witness believed that he was listening to a floatplane, and stopped to watch for it. He heard the engine accelerate, and searched for the airplane to appear above the trees below his vantage point.

Instead, the airplane appeared from between trees traveling northbound, below the treetops, and out over a field "about 50 feet off of the deck." The engine sound was "slow," the airplane's airspeed was "real slow," and the wings rocked from side to side. The pitch attitude continued to increase, but the airplane did not climb. The nose of the airplane then lowered, the engine noise stopped, and the airplane disappeared from view behind a line of trees. Three to four seconds later, the sounds of impact were heard.

According to the witness, "He came out of the trees, not over them. He didn't have speed or altitude. The forward airspeed was not there for the climb. The wings started rocking, and he kept increasing his angle of attack. He was over 45 degrees pitch up."

The witness said that the time from engine start, to engine stoppage was 1 to 2 minutes. He volunteered that the airplane crashed in a "big" field, and that "it was a good old place for a forced landing."

At 0853, the weather reported at Burlington International Airport (BVT), Burlington, Vermont, 8 miles northeast, included clear skies and wind from 170 degrees at 10 knots. The temperature was 81 degrees Fahrenheit, and the dewpoint was 72 degrees Fahrenheit.

The pilot held a private pilot certificate with ratings for airplane single engine land and single engine sea. His most recent FAA third class medical certificate was issued on October 6, 2004. He reported 700 total hours of flight experience on that date.

The airplane was examined at the site by the FAA inspector, and all major components were accounted for at the scene. Control continuity was established from the cockpit to all flight control surfaces. A review of aircraft records revealed that the engine was modified in accordance with FAA Supplemental Type Certificate SE634GL to run on unleaded automotive gasoline.

The FAA inspector also visited the strip from which the airplane departed. He estimated that the strip was between 1,600 feet and 1,700 feet long, and oriented north/south. On July 7, 2005, the airplane was recovered from the site, and moved to the Shelburne Airport (VT8), Shelburne, Vermont.

On July 11, 2005, the engine was removed from the airplane under the supervision of the FAA. The engine was tagged, and shipped to Teledyne Mattituck Aviation, Mattituck, New York. Automotive gasoline was drained from the gascolator and the fuel tank, with no water or sediment noted. Trace amounts of sediment were noted in the gascolator bowl when it was removed.

On September 28, 2005, the engine was removed from its pallet, and placed in a test cell. Examination of the engine revealed a cracked intake manifold pipe on the number 3 cylinder, and a bent exhaust manifold pipe on the number 4 cylinder. The crack in the number 3 pipe was sealed with epoxy.

The right magneto-mounting flange was fractured by impact, and the magneto was displaced in its mount. The magneto was removed, rotated by hand, and reinstalled.

The left magneto was secure in its mount, but two of the four leads at the towers were severed by impact. The lead at the top, number 3 spark plug was also severed by impact, and repaired with tape. The lead at the top, number 1 spark plug was damaged by impact, and repaired.

The carburetor airbox was displaced due to impact, but the carburetor remained intact on its mount. The throttle control arm was free to move through its full range, and was then re-indexed to accommodate the throttle control arm in the test stand.

The carburetor bowl drain plug was removed, and approximately 1/2 ounce of fluid was drained. The fluid was dark yellow in color, with an odor of automotive gasoline and lacquer thinner. The fluid was absent of water and debris.

A club propeller was installed for the test run. The engine was hand-propped for start, and started after the sixth attempt. The engine ran at idle power, but produced no oil pressure. The engine was then stopped.

The engine oil system was primed, and the engine was restarted. The engine idled roughly, and when accelerated to full throttle, ran only to 1,660 rpm. The engine was stopped, and four of the bottom spark plugs were removed and were found oil-soaked. The plugs were cleaned, reinstalled, and the engine restarted. The engine ran to 1,600 rpm, and again was stopped.

Both magneto wiring harnesses were replaced, and the engine was restarted. The engine started immediately, idled smoothly, and accelerated to 2,475 rpm without interruption.

Interpolation of a carburetor icing probability chart revealed that atmospheric conditions at the time of the accident were conducive to "serious icing at glide power."

NTSB Probable Cause

The pilot's failure to maintain adequate airspeed, which resulted in an inadvertent stall, and impact with terrain. A factor in the accident was the partial loss of engine power for undetermined reasons.