SEA98LA072

The pilot reported that during the takeoff, and just after liftoff, the engine lost partial power. The pilot continued to fly the airplane straight ahead and under power lines that were near the end of the airstrip. The tailwheel struck a barbed wire fence before the airplane touched down in a field that was populated with small Christmas trees. The airplane nosed over before coming to rest. Post accident inspection of the engine did not reveal any evidence of a mechanical failure or malfunction, however, contamination was found in the carburetor and the accelerator pump failed to function properly.

On May 7, 1998, at about 1345 Pacific daylight time, a Stinson 108-1, N8659K, registered to a private owner and operated by the pilot as a 14 CFR Part 91 personal flight, nosed over in a field near Toledo, Washington, after the pilot aborted the takeoff due to a partial loss of engine power. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local flight. The airplane was substantially damaged. The airline transport pilot was not injured. One of the two passengers received minor injuries, the second passenger survived the accident and was hospitalized with serious injuries. The second passenger remained in the hospital and died 23 days after the accident.

In a written statement, the pilot reported that earlier in the day the airplane was flown for one hour and thirty minutes without incident. The pilot stated that during takeoff for a third flight, and just after liftoff, the engine lost partial power, rolling back to about 1500 rpm. The pilot continued to fly the airplane straight ahead under power lines that were near the end of the airstrip. The tailwheel struck a barbed wire fence before the airplane touched down in a field populated with small Christmas trees and subsequently nosed over.

After the aircraft was removed from the field and secured, a Federal Aviation Administration inspector from the Seattle, Washington, Flight Standards District Office examined the engine. The inspector removed the air filter from the lower cowling and found it to be clean and clear. The air passageway through the carburetor heat box was clear of obstructions. The carburetor heat valve was functional. The main fuel line to the carburetor was clear. The fuel filter was clean and dry. The carburetor was removed and fuel was present in the carburetor fuel bowl. The accelerator pump discharge nozzle was partially plugged with an unknown substance. The substance was removed and the accelerator pump then functioned normally. The carburetor screen was clean and clear. The spark plugs displayed normal operating signatures. The magnetos produced a spark with hand rotation. Compression was developed in each cylinder and accessory gear and valve train continuity was established. The function of the fuel selector valve was checked and found functional. The valve was disassembled and no leaks or blockages were noted.

The pilot observed that several airworthiness directives on the carburetor had not be complied with, and that he believed that the contamination found in the carburetor was from deteriorating fuel lines.