NTSB Factual Report

On January 1, 2010, about 1108 eastern standard time, a Cessna 150G, N4026J, registered to a private individual, experienced a partial loss of engine power during the climb shortly after takeoff from Doylestown Airport (DYL), Doylestown, Pennsylvania. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal, local flight from DYL. The airplane was substantially damaged and the certificated commercial pilot and one passenger were not injured. The flight originated from DYL about 1106.

The pilot stated that the purpose of the flight was for him to fly the airplane following extensive engine maintenance. He intended on orbiting the airport for 1 hour, then intended on landing and having a mechanic (passenger), visually inspect the engine. A total of approximately 6 gallons of 100 low lead (100LL) fuel were in each fuel tank as determined by a dipstick and confirmed by the fuel quantity gauges. No contaminants were noted in either fuel tank or gascolator during his preflight check, and he did not notice any discrepancies during the engine run-up before takeoff.

The pilot further stated that after takeoff during climb out when the flight was between 50 and 75 feel above ground level, he noticed a partial loss of engine power. With trees ahead he turned to the right towards an open field and while in a right turn, the right main landing gear contacted the ground. The left main landing gear then contacted the ground causing the gear to separate. The airplane came to rest upright in a left wing low attitude which resulted in fuel leaking from the left fuel cap.

Inspection of the accident site by a Federal Aviation Administration (FAA) inspector revealed the airplane was resting in the middle of a corn field with the left and nose landing gears separated. A small fire in the engine compartment had been quickly extinguished. The airplane was recovered for further examination.

Inspection of the engine by an FAA airworthiness inspector following recovery of the airplane revealed the air induction housing was crushed around the carburetor, but there were no obstructions of the air induction system. The air induction filer which had been separated and recovered from the accident site was determined to have been properly installed. The throttle, mixture, and carburetor heat control cables were connected and properly attached; however, impact damage precluded range of motion checks. The accelerator pump of the carburetor operationally checked good. The spark plugs were new and exhibited light gray coloration of the porcelain insulator. The engine was rotated by hand and spark was noted at all spark plugs, and compression was noted in all cylinders. No indication of a failure or malfunction was noted to the muffler.

A surface observation weather report taken at DYL at 1054, or approximately 14 minutes before the accident indicates in part that the dry bulb and dew point temperatures were 35 and 33 degrees Fahrenheit respectively, and the relative humidity was 92 percent.

According to FAA Special Airworthiness Information Bulletin (SAIB) CE-09-35, based on the recorded temperature and dew point about the time of the accident, the conditions were favorable for serious carburetor icing at cruise power setting.

FAA Advisory Circular (AC) 20-113 dated October 22, 1981, titled, “Pilot Precautions and Procedures to be Taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems” states that induction system icing is more likely when the temperature is below 70 degrees Fahrenheit and the relative humidity is above 80 percent.

An overhauled engine was installed the day before and test run after installation. The recording tachometer time at the time of installation was 6,275.32, while the tachometer at the time of the accident was 6,275.41.

NTSB Probable Cause

A partial loss of engine power due to carburetor icing.