Primary finding
Probable cause
the improper modification of the fuel system by the pilot-in-command. A factor was bockage of the fuel system screen.
Investigator assessment
Analysis narrative
The amatuer built airplane sustained a total loss of engine power while in cruise flight. During the forced landing the airplane sustained substantial damage. A post accident examination revealed that a fuel system screen was blocked with a substance the pilot-in-command stated was a sealing compound he had used in the fuel tank. The pilot stated he did not remove the fuel screen while performing maintenance on the fuel system.
Source record
Factual narrative
HISTORY OF FLIGHT On August 4, 1993, at 0930 cdt, an experimental Kit Fox IV, N127RF, registered to Raymond Fulwiler made a forced landing seven (7) miles northeast of Green Bay, Wisconsin, while on a pleasure flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was substantially damaged. The private pilot and passenger were not injured. The flight originated from Green Bay, Wisconsin (GRB)on August 4, 1993 AT 0920 cdt. Ten minutes after takeoff, the pilot indicated the engine "sputtered" and stopped, resulting in a forced landing in a willow marsh. The aircraft damage included the wooden propeller, engine cowl and structural failure of the lower cabin area tubular fuselage. AIRCRAFT INFORMATION The Kit Fox IV is a 2 place side by side, high wing monoplane of truss construction with conventional landing gear. The wing has two (2) aluminum tubular spars, for and aft. The wings carry 12 gallons of fuel in two (2) 6 gallon RH & LH fiber glass wing tanks. The aircraft is powered by a Rotax "912" liquid/air cooled 80 HP engine. TEST AND RESEARCH Both fuel tanks are cap vented (pressure tube). A common fuselage mounted header tank is vented to the RH tank. The vent system was clear and unobstructed. The LH tank was empty. The RH tank had approximately 5 gallons of fuel remaining. The fuel header tank was also empty. When the fuel outlet line was removed from the RH tank, only a small amount of fuel (2oz.) was observed. The RH fuel outlet screen was completely covered with a fuel tank sloshing/sealer compound (trade name --KREEM). This sealing compound obstructed fuel flow by covering and sealing the fuel outlet screen installed in the tank. The pilot/builder indicated he had recently sloshed the tank in an effort to seal a seam leak. He did not remove the outlet screen in the process. When fuel was put in the LH tank, fuel flow was normal and the engine ran with no abnormalities noted. -