GA SMA ENGINE FAILURE ON FINAL FORCED SHORT OF ARPT.

Narrative

ENCLOSED YOU WILL FIND A COPY OF THE STATEMENT I HAVE MAILED TO THE FAA CONCERNING THE EVENTS OF 2/88. THE DAMAGE SUSTAINED BY THE ACFT CONSISTED OF BENT NOSE COWLING; SEPARATED NOSE GEAR; AND BENT PROP TIPS (NOT CONSIDERED SUBSTANTIAL DAMAGE) DUE TO THE FORCED LNDG. AT THE PRESENT TIME I STILL DO NOT KNOW EXACTLY WHY THE ENG FAILED. MY MAIN PURPOSE IN WRITING THIS RPT IS TO HIGHLIGHT A PROB THAT HAS CONCERNED ME. THAT PROB IS ACCURATELY JUDGING THE AMOUNT OF FUEL REMAINING IN AN ACFT'S FUEL TANKS. AS YOU CAN SEE IN MY STATEMENT; DURING MY BANNER TOWING OPS; I RELIED ON FUEL BURN AND TIME ALOFT TO JUDGE FUEL REMAINING. AS THEY ARE ON MOST LIGHT; GA ACFT; THE FUEL GAUGES ON THIS ACFT ARE VERY UNRELIABLE. IT IS VIRTUALLY IMPOSSIBLE TO ACCURATELY KNOW HOW MUCH FUEL HAS BEEN USED. THE OBVIOUS SOLUTION TO THIS PROB WOULD BE INSISTING ON INSTALLATION OF HIGH QUALITY; ACCURATE FUEL GAUGES IN ALL ACFT. ANOTHER PROB THAT I FEEL MAY HAVE POSSIBLY BEEN A FACTOR IN MY SITUATION IS THE INSTALLATION OF BLADDER TYPE FUEL TANKS; ESPECIALLY IN OLDER ACFT. THE POTENTIAL FOR THESE CELLS TO DEVELOP WRINKLES; OR TO SAG/SHRINK; COULD REDUCE THE AMOUNT OF USABLE FUEL AVAILABLE. A PLT PREPARING FOR A FLT HAS ONLY HIS AIRPLANE FLT MANUAL TO GUIDE HIM AS TO HOW MUCH FUEL IS AVAILABLE FOR HIS OPERATION. STATEMENT OF EVENTS: I DID A NORMAL PREFLT INSPECTION. THIS INCLUDED VISUALLY CHKING BOTH WING TANKS AND DRAINING FUEL FROM THE 2 WING TANK QUICK DRAINS AND FUEL SELECTOR QUICK DRAIN. MY INSPECTION REVEALED THAT BOTH TANKS WERE TOPPED OFF AND THE FUEL SHOWED NO SIGNS OF WATER OR SEDIMENT. THE AIRPLANE FLT MANUAL IN THE ACFT SHOWS THIS ACFT CARRYING 65 GALS TOTAL FUEL OF WHICH 55 GALS IS USABLE. IT ALSO STATED THAT 7 GALS OF THE 10 GALS UNUSABLE FUEL IS AVAILABLE IN LEVEL FLT. TO BE SAFE; I ALWAYS CONSIDERED JUST THE 55 GALS AS USABLE. I WAS TO JUDGE FUEL QUANTITY BY TIME AND FUEL BURN WITH MAX FLT TIME TO BE 4 HRS WITH THE REQUIRED 30 MINS RESERVE. PRIOR TO MY LAST FLT; I PULLED 3 BANNERS: THE FIRST ONE FOR .5 HRS; THE NEXT 2 FOR 1.1 HRS EACH (TOTAL: 2.7 HRS). AFTER DROPPING EACH BANNER; I LANDED AND SHUT DOWN THE ACFT TO WAIT FOR THE GND CREW TO BRING ME ANOTHER HOOK. MY LAST TOW WAS TO LAST AN HOUR. I KNEW IF I FLEW A 1/2 HR S; THEN THE TRIP HOME SHOULD BE SHORTER DUE TO THE TAILWIND; KEEPING MY RESERVE ON THE SAFE SIDE. THE CTLR SUGGESTED I ENTER LEFT TFC FOR RWY 29 AFTER THE DROP; WHICH I AGREED WITH. I DROPPED THE BANNER AND CLBED STRAIGHT AHEAD TO 600'. I MADE A LEFT TURN AND ENTERED LEFT DOWNWIND FOR RWY 29 CONTINUING MY CLB. I LEVELED OFF AT 800' DUE TO LOW CLOUDS OVER THE ARPT. I COMPLETED THE WRITTEN PRELNDG CHKS; IE SEAT BELT ON; FUEL BOTH; MIXTURE RICH; PROP HIGH; CARB HEAT ON. AT ABOUT 400'; THE ENG SOUNDED LIKE A CYLINDER WAS MISFIRING. THIS LASTED ONLY A COUPLE OF SECS. AT ABOUT 200'; THE ENG FELT LIKE IT QUIT ALTOGETHER. AS I STARTED SINKING; I CHKED MIXTURE RICH AND CARB HEAT OUT AND PUMPED THE THROTTLE TWICE WITH NO EFFECT. THERE WAS A GOLF COURSE BELOW ME AND I KNEW I WOULD NOT MAKE THE CLR ZONE TO THE RWY. I DID MY BEST TO GUIDE THE AIRPLANE BTWN A GROUP OF PALMS ON THE LEFT AND A PINE TREE ON THE RIGHT. THE ACFT TOUCHED DONE IN WHAT FELT LIKE A LEVEL ATTITUDE. AT THAT POINT I FELT RELIEVED AND THAT THE AIRPLANE WOULD BE ALRIGHT. AS I LOST ELEVATOR EFFECTIVENESS; I LOWERED THE NOSE AND REALIZED THE NOSE GEAR HAD COLLAPSED. THE ACFT STOPPED IN A NOSE DOWN ATTITUDE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: FAA INVESTIGATED THE INCIDENT AND DID CHK AND WERE ABLE TO DRAIN FUEL OUT OF THE ACFT. STATED THEY DRAINED SO MUCH; BUT HE DOES NOT KNOW HOW MUCH WAS ACTUALLY REMAINING. PROBABLY WOULD HAVE BEEN NO DAMAGE FROM THE OFF ARPT LNDG; BUT A PWR LINE HAD JUST BEEN BURIED ACROSS HIS LNDG PATH AND THE SOFT DIRT IN THE FILLED IN TRENCH CAUGHT THE NOSE WHEEL CAUSING THE DAMAGE. SINCE DAY OF INCIDENT AND A LETTER SAYING FAA WAS INVESTIGATING THE INCIDENT AND SUBMITTING HIS STATEMENT; HE HAS HEARD NOTHING MORE FROM FAA.