A KITFOX 111 HOME BUILT'S ENG RAN ROUGH THEN STOPPED SHORTLY AFTER TKOF AT 1000 FT. OFF FIELD LNDG ACCOMPLISHED. CAUSED BY BLOCKED FUEL LINE.

Narrative

SHORTLY AFTER TKOF ALONE IN HOMEBUILT KITFOX 10 YRS OLD; FROM PRIVATE FIELD; THE ENG RAN ROUGH AND THEN STOPPED. THE PLANE WAS LANDED SAFELY AND THANKFULLY FROM ABOUT 1000 FT AGL IN A HAYFIELD TWO MILES FROM THE HOME STRIP. LATER IN THE HAYFIELD THE ENG WAS STARTED AND IT RAN BUT WAS NOT TRUSTED TO FLY. EXAMINATION SHOWED A FUEL BLOCKAGE FROM THE WING TANKS TO THE ENG. A SHORT LENGTH OF RUBBER TUBING USED TO JOIN ALUMINUM TUBES SWELLED SHUT. THE FAILED RUBBER TUBING WAS AVIATION GRADE MIL H 6000. FUEL USED WAS HI TEST AUTO GASOLINE. SERVICE TIME WAS EIGHT YRS BEFORE BLOCKAGE. AUTOMOTIVE GRADE FUEL TUBING USED AT OTHER PLACES DID NOT FAIL. WE THINK THIS COULD AFFECT SAFETY OF OTHER PLTS. PREVENTION SUGGESTIONS (ANY ONE): 1) MEASURING FUEL FLOW INTO A CONTAINER ON AN ANNUAL BASIS COULD HAVE FOREWARNED THIS BLOCKAGE. 2) A REPLACEMENT OF RUBBER TUBING PARTS AT FIVE-YEAR INTERVAL WOULD SEEMINGLY HAVE PREVENTED THIS BLOCKAGE. 3) CHOICE OF CORRECT TUBING FOR AUTO GASOLINE WOULD HAVE PREVENTED THIS BLOCKAGE USING AUTO GASOLINE. (AUTOMOBILE GRADE TUBING DID NOT FAIL). CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED AT THE PRESENT TIME A CONTROVERSY IS ON GOING MAINLY ON THE INTERNET WHETHER MIL H 6000 SHOULD BE USED ONLY FOR AVIATION GRADE FUEL OR IS OK FOR AUTOMOTIVE FUEL. THE RPTR SAID THE TUBING USED ON THIS AIRPLANE IS OF THE SAME AGE 8 YRS AND ONLY THE MIL SPEC 6000 BECAME BLOCKED. THE RPTR STATED THIS AIRPLANE WAS FUELED AND OPERATED EXCLUSIVELY ON PREMIUM AUTOMOTIVE FUEL. THE RPTR SAID THIS AIRPLANE IS NOT FLOWN FREQUENTLY AND HAS ONLY 300 HRS TOTAL TIME. THE RPTR MAKES A SAFETY SUGGESTION THAT ONLY AUTOMOTIVE FUEL TUBING BE USED IF THE AIRPLANE USES AUTOMOTIVE FUEL.