C177 PLT HAS FUEL STARVATION AND MAKES AN OFF ARPT LNDG.

Narrative

I ARRIVED AT ZZZ1 ARPT FOR FLT TO ZZZ2. PURPOSE OF FLT WAS TO PICK UP MY SON ON THE ISLAND. I PERFORMED A PREFLT INSPECTION; AND ALSO CHKED LOG TO SEE WHEN PLANE WAS LAST FLOWN. LOG SHOWED FLT PREVIOUS DAY; AND INDICATED FUEL TANK WAS TOPPED OFF; AS PER NORMAL PROC. I VISUALLY CHKED TANKS AND VERIFIED THAT THEY WERE FULL. MY FLT PLANNING HAD INDICATED AN ENRTE TIME OF APPROX 2 HRS 2 MIN. I PLANNED TO FLY TO ZZZ2; PICK UP MY SON; AND RETURN WITHOUT REFUELING. I CHOSE NOT TO REFUEL BASED ON THE FACT THAT THE AIRPLANE HAS A RANGE OF 5.8 HRS WITH FULL TANKS ACCORDING TO POH AND MY OWN PERSONAL EXPERIENCE OF PREVIOUS 4 HR TRIPS WITH PLENTY OF FUEL IN RESERVE. ALSO; I WANTED THE AIRPLANE TO BE A LITTLE LIGHT; DUE TO THE FACT THAT ZZZ2 HAS A 3000 FT RWY OVER WATER. AND I WANTED TO MAKE SURE THAT I HAD AS MUCH ALT AFTER TKOF AS POSSIBLE; BEFORE I HAD TO FLY OVER THE GULF WATERS; KNOWING THAT BURNING OFF 2 HRS OF FUEL WOULD REDUCE MY WT; AND HAVING TAKEN ABOUT 2.1 HRS TO ARRIVE; I CALCULATED I WOULD HAVE AT LEAST 3.4 HRS OF FUEL REMAINING FOR RETURN TRIP. THE RETURN TRIP TO ZZZ1 WAS ON SCHEDULE FOR ANOTHER 2 HR DURATION WHEN THE ENG SUDDENLY STARTED RUNNING VERY ROUGH ABOUT 11 MI SE OF ZZZ ARPT. I STARTED CHKING INSTS AND GAUGES FOR SOURCE OF PROB. I PULLED CARB HEAT AND VERIFIED THAT MIXTURE WAS FULL RICH; AND SET UP BEST GLIDE SPD AND TURNED TOWARDS ZZZ. AT THIS TIME; I WAS IN RADAR CONTACT WITH ZZZ ATC; AND DECLARED AN EMER. I THEN SCANNED MY HOBBS METER; AND NOTED IT WAS SHOWING 4 HRS ON METER; SO I ASSUMED THAT IT WAS NOT A FUEL STARVATION PROB; BUT SOME ENG MALFUNCTION. I TURNED ON MY AUX FUEL PUMP SWITCH AND VERIFIED THAT FUEL SELECTOR WAS SET TO BOTH TANKS. WHEN I WAS APPROX 4 MI FROM ZZZ; I CALCULATED THAT I WOULD NOT BE ABLE TO MAKE THE ARPT; AND I KNEW THAT THERE WERE RESIDENTIAL AREAS BTWN MYSELF AND THE ARPT; WITH VERY FEW ALTERNATE LNDG SPOTS. I THEN DECIDED TO PICK A FIELD TO LAND IN; AND NOTICED THAT OFF TO MY R WAS A FIELD THAT LOOKED TO BE APPROX 4000 FT LONG AND IN PERFECT POS FOR A R TURN FOR FINAL BASED ON MY ALT AND SINK RATE. I MADE ANOTHER CALL TO ZZZ ATC AND NOTIFIED THEM THAT I WAS GOING TO MAKE LNDG IN FIELD E OF ZZZ. AT THIS POINT; THE ENG WAS COMPLETELY DEAD; SO I SHUT DOWN ALL SWITCHES AND IGNITION IN PREPARATION FOR LNDG; AND DID NOT WANT TO CHANCE A FIRE FROM FUEL LEFT IN TANKS (I WAS STILL ASSUMING I HAD ABOUT 13 GALLONS LEFT IN TANKS). I CLRED THE TREE LINE ON THE W SIDE OF FIELD; AND AS I GOT LOWER; I REALIZED IT WAS A CORN FIELD WITH BABY CORN STALKS (ABOUT 10 INCHES HIGH) WITH ROWS; SO I LINED UP WITH THE ROWS AND PERFORMED A SOFT FIELD LNDG. THE AIRPLANE TOUCHED DOWN FAIRLY SOFTLY; WITH A VERY SHORT ROLLOUT. AFTER A FEW MOMENTS; I TURNED BACK ON MASTER SWITCH AND AVIONICS AND CALLED ZZZ ATC TO LET THEM KNOW I WAS DOWN SAFELY. AN AIRPLANE ABOVE ME RELAYED THE MESSAGE; AND THEY NOTIFIED ME THAT EMER PERSONNEL HAD BEEN NOTIFIED. MY SON AND I EXITED THE AIRPLANE TO ASSESS DAMAGES. THE AIRPLANE APPEARED TO BE UNDAMAGED; AND THE CORN FIELD ONLY HAD ABOUT 100 FT OF DAMAGE ON 1 OR 2 ROWS TO THE CORN STALKS. I THEN GOT A SMALL STEPLADDER OUT OF THE BACK OF AIRPLANE TO CHK TANKS; AND NOTED THAT THEY WERE COMPLETELY EMPTY. I BELIEVE THE PROB IS A FUEL LEAK SOMEWHERE IN THE PLANE; BUT AS OF YET; NO MECH HAS BEEN ALLOWED TO CHK THE PLANE UNTIL THE FAA GIVES PERMISSION.