NTSB Factual Report

On August 2, 2003, at 1730 central daylight time, a Beech 19A single-engine airplane, N7643R, was substantially damaged during a forced landing following a partial loss of engine power during take off from the Gillespie County Airport (T82), near Fredericksburg, Texas. The private pilot and the passenger were not injured. The aircraft was owned, and operated by a private individual. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight originated from T82, and had Midland Airpark (MDD), near Midland, Texas, as the planned destination.

According to the pilot statement, the engine lost power during the initial climb through 500 feet. The pilot turned the airplane toward the airport, and was able to clear nearby power lines. During the forced landing, the aircraft landed outside the airport boundary, bounced, and came to rest in a field approximately 25 feet from the airport perimeter fence.

After touchdown on the dirt, the aircraft ground-rolled, skidded and came to rest level and upright in a open field, just outside of the airport boundary fence. The aircraft was mostly intact except for the right main landing gear strut, which broke off approximately four inches from its base; the right side of the trailing edge of the horizontal stabilizer was bent up and an outboard portion was sheared; the left side wall of the empennage was buckled approximately three feet in front or the stabilator's leading edge; and the wingtip of the right wing showed scratches and became unfasten.

The pilot reported that he had accumulated a total of 330 hours of flight time, of which 320 were in the same make and model as the accident airplane. The pilot held a valid third class medical certificate issued on November 20, 2002.

The FAA inspector reported that the annual inspection was overdue. The most recent annual inspection was completed on July 19, 2002. The inspector added that improper maintenance procedures used in the installation of the air filter and overdue annual inspection rendered the aircraft un-airworthy.

The aircraft was transported from the accident site to the airport ramp, where the airframe, fuel system and engine were examined by the FAA inspector.

Inspection of the induction system revealed that part of the filtering foam of the air filter was pinched between the filter screen and filter box. Further examination of the carburetor by Precision Airmotive Corporation, revealed that a 6 inch long and 1/4 inch wide piece of the filtering element was found lodged over metal vanes located at the carburetor venturi. The foam was removed from the venturi, and documented by the investigator. The rest of the inspection found that all induction ducts and the carburetor components were found secure and without signs of abnormalities.

A run-up was conducted after the aircraft was secured. The engine start was normal and all engine gauge indications were normal. The engine performed faultless, both, with and without turning the fuel boost pump on; the magneto drop check was also normal. The FAA inspector conducting the run-up described the tachometer's green arc extending from 2,200 to 2,700 RPM (red line); however, the certificated full throttle RPM range for this engine and propeller combination during the prevailing meteorological conditions of the day should have been 2,300 to 2,400 RPM. The engine only reached 2,200 RPM.

After the run-up, an engine compression check was conducted. The results provided the following ratios: # 1: 72/80, #2: 75/80, #3: 0/80, #4: 66/80. The engine produced high blow-by on number 3 cylinder, and moderate blow-by through the breather.

After the test-run, the carburetor was removed and sent to its manufacturer to be inspected, and to have a flow test performed. According to the manufacturer representative, the carburetor components and float (P/N 30-766) were correct; there was no water or other contaminants found; and its operational test was normal. The carburetor flow test showed the fuel consumption slightly outside limits in midrange settings (.5 pound of fuel richer per hour at an airflow of 92 cubic feet/min, and 2 pounds richer per hour at an airflow of 160 cubic feet/min); however, these quantities are not enough to affect engine performance and cause a sudden RPM drop.

The carburetor representative reported that: "The piece of foam would have not only reduced the airflow to the engine, but also caused the air fuel mixture to become too rich, both of which would tend to reduce power output."

NTSB Probable Cause

A partial loss of engine power due to a rich mixture and reduced airflow to the engine. Contributing factors were the owner's failure to obtain an annual inspection, and improper maintenance procedures used in the installation of the air filter.