NTSB Factual Report

On August 1, 2007, about 1130 eastern daylight time, a Piper J3C-65, N5721N, registered to and operated by a private individual as a Title 14 CFR Part 91 personal flight, crashed shortly after taking off from a private field in Andersonville, Georgia. Visual meteorological conditions prevailed, and no flight plan was filed. The private-rated pilot and one passenger received serious injuries, and the airplane incurred substantial damage. The flight was originating at the time of the accident.

An FAA inspector responded to the scene of the accident, and stated that he examined the wreckage and found fuel to be present in the airplane, but noted no obvious anomalies. He further stated that he interviewed several witnesses who said that the pilot was giving airplane rides to construction workers, who had been working on his house. According to the inspector, the witnesses said that the pilot was taking off and landing on his private landing strip, while giving the airplane rides, and he had given rides to four workers. In the process of giving the fifth and final airplane ride, during initial climb after takeoff, the airplane's engine ceased operating. He said that the witnesses said that they observed the airplane as it turned about 180 degrees in the direction of the runway from where it had just departed, but it descended quickly and impacted the ground in a level attitude.

A postcrash examination was performed by the NTSB, along with a representative of Teledyne Continental Motors. The examination revealed that several engine mounts had fractured during the impact, and that the carburetor had separated from it's attach point to the engine manifold. In addition the oil sump had been crushed, and the propeller flange and propeller had been bent beyond the permissible limits of a test run.

During the course of the examination the engine was removed from the airframe, and parts which exhibited damage consistent with the damage having occurred during the accident, were replaced. The parts that were replaced include, the intake manifold, oil sump, and the propeller flange. In addition, a club propeller was fitted.

The engine was then given a test run, and initially during the test, when fuel was added, the fuel "poured from" the carburetor, consistent with the needle valve having been stuck in the open position due to an obstruction. After tapping on the side of the carburetor with a screwdriver handle, the obstruction was cleared, and fuel stopped flowing out of the carburetor. The test run was then completed with no other anomalies being noted.

A follow-on teardown examination of the carburetor revealed the presence of debris within the carburetor float bowl, of a size that was capable of blocking the needle valve, or fuel metering orifice.

NTSB Probable Cause

The pilot's improper decision to make a 180-degree turn at low altitude to return to the departure runway following a loss of engine power during takeoff-initial climb. A factor in the accident was contamination in the carburetor.