CEN13LA304

The pilot/owner, who also built the airplane, reported that, during the initial climb, the airplane stopped climbing about 30 ft above the ground and then experienced a loss of engine power. The airplane subsequently nosed over and impacted terrain. The pilot reported that he used automotive gasoline to fuel the airplane, which was powered by a Volkswagen engine with a POSA-type carburetor. Further, the engine was tightly cowled, but the gascolator on the airplane was not insulated and was mounted about 2 inches from the exhaust pipe. Airplanes configured in this manner are susceptible to vapor lock when operating with automotive gasoline. The circumstances of the accident are consistent with a loss of engine power due to vapor lock.

On May 11, 2013, at 1755 eastern daylight time, an Ankerstar Bradley D. Rand-Robinson KR2, N774A, impacted terrain near Butler County Regional Airport (HAO), Hamilton, Ohio, following a loss of engine power shortly after takeoff. The pilot, who was the sole occupant, was seriously injured. The airplane sustained substantial damage. The airplane was registered to a private individual and operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight which was not operating on a flight plan. The flight originated from Butler County Regional Airport (HAO), Hamilton, Ohio at 1755. The pilot stated that after take-off and the initial climb at 80 knots, the airplane stopped climbing about 30 feet above the runaway. He then leveled off at 70 knots, and the engine lost power. With the propeller still spinning, the airplane nosed over and impacted the ground approximately 1000 feet beyond the runaway. The airplane had not flown since 2010, when it experienced a hard landing and a propeller strike. One witness recalled the airplane owner had complained to him the airplane had trouble producing power and maintaining RPM following the first accident. The pilot conducted several high speed taxi tests and partial power engine runs in the airplane the day of the accident. These events were conducted in accordance with FAA Advisory Circular 90-89A, Amateur Built Aircraft and Ultralight Flight Testing Handbook. The engine was not run at full power prior to the attempted takeoff. The pilot indicated that he used automotive gas from a gas can located in hangar to fuel the airplane. According to a person of expertise, the use of automotive gas in a Volkswagen engine with a POSA type carburetor (Revflow) causes a greater potential for vapor lock, as the automotive gas has a lower boiling point than Avgas. Furthermore, in a Volkswagen engine that is tightly cowled, the fuel lines should be insulated to protect against engine heat, and often outside air is piped in for cooling of fuel components including a gascolator. The gascolator on the mishap airplane was not shrouded or insulated, and was mounted approximately 2 inches aft of an exhaust pipe. A fuel test was performed on a fuel sample taken from the can, and a fuel sample taken from the mishap airplane. Fuel test result show that there was a difference of total aromatics between samples; the sample from the can was 48%, and the sample from the tank was 57%.