A BC65 PLT EXPERIENCED ENG FAILURE; LIKELY DUE TO FUEL CONTAMINATION; AND EXECUTED A FORCED LNDG.

Narrative

I DEPARTED ZZZ1 FOR ZZZ2 AT OR ABOUT XA25. THE ACFT OPERATED NORMALLY UP TO APPROX 15-20 MINS INTO THE FLT. THE ENG BEGAN MALFUNCTIONING (QUIT RUNNING 1 SECOND; THEN WOULD RUN NORMALLY). IT CONTINUED TO OPERATE INTERMITTENTLY (OFF FROM 2 SECONDS AND ON FOR 8-12 SECONDS). I IMMEDIATELY APPLIED CARB HEAT IN HOPES THAT IF CARB ICE WERE CAUSING THE PROB; THINGS WOULD CLR UP. CARB HEAT DID NOT MAKE ANY DIFFERENCE IN THE INTERMITTENT CONDITION OF THE ENG. AFTER ABOUT 45 SECONDS TO 1 1/2 MINS OF THIS INTERMITTENT ACTIVITY; I CONCLUDED THIS WAS NOT GOING TO CLR UP AND STARTED LOOKING FOR A PLACE TO LAND. I DECIDED TO RETURN TO ZZZ1 AND REMEMBERED A PVT FIELD I HAD PASSED APPROX 5-8 MINS PRIOR. WITH THE PVT FIELD IN SIGHT; THE INTERMITTENT ENG BECAME AN INOP WINDMILLING ENG; AT WHICH POINT I SET UP FOR A PWR-OFF GLIDE ONTO THIS PVT AIRFIELD. I CROSSED OVERHEAD THE FIELD AT 2000+ FT AGL AND BEGAN SETTING UP FOR AN OVERHEAD APCH. ORCHARDS SURROUNDED THE RWY. ON DOWNWIND; ABEAM OF MY INTENDED TOUCHDOWN POINT; I NOTICED A PWR LINE XING THE APCH OF MY INTENDED RWY. I TURNED BASE AND FINAL INTENDING TO BE HIGH ON FINAL TO CLR THE PWR LINES. I SLIPPED THE AIRPLANE ONCE I KNEW I HAD THE RWY AND THE PWR LINES MADE. I STILL FOUND MYSELF AT ABOUT 300 FT WITH THE REALIZATION OF THE FACT THAT I WAS GOING TO BE HIGH AND FAST TOUCHING DOWN MIDFIELD WITH AN AIRPLANE WITH MINIMAL BRAKING CAPABILITY (ORIGINAL BRAKES). AT THIS POINT; I DECIDED TO ABANDON THIS RWY AND LAND IN A FALLOW FIELD S OF THIS ORCHARD. THE FIELD WAS DIRT AND SMALL WEEDS WITH A FIELD OF GRAPES TO THE N WITH VINES 4 FT HIGH AND ANOTHER FIELD WITH A CROP S OF MY INTENDED LNDG. THE APCH TO THIS FALLOW FIELD HAD NO OBSTACLES TO THE N. WHEN I KNEW I HAD THE FIELD MADE; I SLIPPED THE ACFT AGAIN TO MAKE MY DESIRED TOUCHDOWN POINT. THE ACFT TOUCHED DOWN (IN A 3-POINT ATTITUDE) N OF THE E/W PWR LINE ON THIS FIELD. ONCE DOWN; THE ACFT DIDN'T SLOW DOWN AS QUICKLY AS I THOUGHT IT WOULD. AT A SPD OF 10-15 MPH; I ROLLED INTO A YOUNG CITRUS ORCHARD S OF THE LNDG FIELD. THE ACFT CAME TO A STOP RESTING ON ITS MAIN GEAR AND ITS NOSE. I WAS THE SOLE OCCUPANT AND EXITED THE ACFT AS SOON AS IT CAME TO A STOP. THERE WAS VERY MINIMAL DAMAGE TO THE ACFT CONSISTING OF: 2 OR 3 DENTS (2 INCHES DEEP) TO THE LEADING EDGE OF THE WINGS; ONE 6-INCH GASH IN THE FABRIC UNDER THE L WING; AND ONE 6-INCH GASH IN THE FABRIC UNDER THE L AILERON. THE AIR FILTER SCREEN WAS BROKEN. THE PROP WAS UNDAMAGED. THE TENSION STRUT UNDER THE L MAIN GEAR WAS SLIGHTLY BENT. I AM A CERTIFIED A&P MECH. MY SUBSEQUENT INVESTIGATION REVEALED LITTLE OR NO CONTAMINATION DRAINED FROM THE FIREWALL MOUNTED GASCOLATOR UNIT DRAIN. THE CARB BOWL WAS DRAINED AND I FOUND ALMOST 2 TABLESPOONS OF WATER IN THE FUEL. THE CARB FUEL FINGER SCREEN CAVITY SHOWED SOME CONTAMINATION DEBRIS THAT WAS OF A GRAINY OR RUSTY NATURE; IN ADDITION TO A SLIMY; GRAVY TYPE CONSISTENCY. REMOVAL OF THE GASCOLATOR BOWL REVEALED LARGE FLAKES OF CONTAMINATION OF A PASTE NATURE IN THE BOTTOM OF THE BOWL ABOUT 1/8 INCH DEEP. THIS MATERIAL SIZE WAS TOO LARGE TO DRAIN THROUGH DRAIN VALVE. THE VERY FINE SCREEN IN THE UPPER PART OF THE GASCOLATOR WAS CONSIDERABLY CLOGGED WITH A MILKY WHITE FILM. I SUSPECT THE ENG FAILURE WAS CAUSED BY FUEL STARVATION IN 1 OF 3 POSSIBLE WAYS: 1) DEBRIS AND A MAIN JET PASSAGE OF THE CARB; 2) FUEL RESTR BY THE FLAKES OF THE GASCOLATOR; OR 3) BUILD-UP OF WATER IN THE CARB BOWL. FURTHER INVESTIGATION INTO THE INCIDENT REVEALED THE ACFT HAD BEEN FLOWN MARCH OR APRIL OF 2005. IT ALSO HAD A FULL PWR RUN-UP 1 MONTH PRIOR TO THE INCIDENT. I FLEW IT FOR 40 MINS THE DAY BEFORE THE INCIDENT WITH NO INDICATIONS OF ABNORMALITIES. IN THE FUTURE WHEN FACED WITH AN ACFT THAT HAS BEEN SITTING IDLE FOR A LONG PERIOD OF TIME; I PLAN TO THOROUGHLY (DISASSEMBLE FUEL SCREENS) INSPECT THE FUEL SYS. NORMAL PREFLT FUEL DRAIN DID NOT REVEAL ANY CONTAMINATION.