CEN09LA330

A partial loss of engine power due to an obstruction of the air intake, as reported by the pilot. Contributing to the accident was the pilot's insufficient preflight inspection.

The private pilot conducted a run-up of the experimental airplane's 65-horsepower engine prior to departure, since it had not been flown in the past 90 days. The engine produced full power and the pilot departed the private airstrip. Shortly after takeoff, the engine started to gradually lose power and the airplane was unable to maintain a normal climb rate. The pilot returned to the airport, but had to execute a go-around due to another airplane being on the runway. When he applied full power, black smoke was observed "belching" from the exhaust and the engine power continued to decline. The pilot made a forced landing to a field adjacent to the airstrip and subsequently the airplane sustained structural damage. The pilot reported that there was no air filter installed on the engine and he thought that a nest of mud-dauber wasps had built a nest in the air intake, vibrated loose, and was ingested into the carburetor intake.

On May 31, 2009, approximately 1852 central daylight time, N59357, an experimental Frey Fly Baby airplane, sustained substantial damage during a forced landing to a field after a reported loss of engine power near Roanoke, Texas. The private pilot/builder/owner sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight conducted under 14 Code of Federal Regulations Part 91. In a written statement, the pilot said that he had not flown the airplane in the past 90 days, so he did a full engine run-up prior to departure with no discrepancies noted. Shortly after take-off, the pilot noted that the airplane was not climbing as expected and elected to return to the airport and check the engine, which was gradually losing power. As he was approached the airport, another airplane taxied onto the runway, so he elected to go-around by adding power and initiating a climb. However, the engine would not produce full power and the pilot was unable to maintain altitude. Witnesses also observed black smoke "belching" from the engine exhaust. The pilot made a forced landing to a field adjacent to the airport. He said, "Unfortunately, the landing resulted in the complete destruction of the aircraft..." The pilot felt that Texas mud-daubers had built a nest in the air intake, vibrated loose, and was ingested into the carburetor intake. There is no air filter on this engine. He said, "Mud-dauber wasps are very common in this part of Texas. Removing their mud nests is a big part of an annual inspection." Weather at Fort Worth Alliance Airport (AFW), about 10 miles west of the accident site, at 1853, was reported as winds from 170 degrees at 8 knots, visibility 10 miles, few clouds at 7,000 feet, temperature at 31 degrees Celsius, dewpoint 16 degrees Celsius, and a barometric pressure setting of 29.85 inches.