CH2000 MADE A FORCED LNDG IN A GRASS FIELD DUE TO ENG FAILURE.

Narrative

AFTER TOPPING OFF THE ACFT AND COMPLETING OUR PREFLT CHK; WE PROCEEDED TO ENTER THE PLANE AND CONTINUE OUR TRIP NORTHWARD TO ZZZ. WE DEPARTED AT APPROX XA50. ALONG OUR RTE OF FLT WE PAID CLOSE ATTN TO OUR FUEL SITUATION AND PERIODICALLY SWITCHING TANKS TO HELP BAL THE ACFT. AS WE APCHED THE ZZZ AREA; WE WERE ON A 3 MI FINAL FOR RWY 36 AND HAD OUR FIRST EXPERIENCE WITH THE ENG ROUGHNESS. IN THOSE FEW SECONDS IT PROCEEDED TO GET WORSE AND WE INSTINCTIVELY PULLED THE CARB HEAT CTL ON. THE ENG CAME BACK TO LIFE 100%. SEVERAL SECONDS LATER; WE HAD OUR SECOND ENCOUNTER. THE ENG GOT VERY ROUGH AND I INSTINCTIVELY THIS TIME SWITCHED THE FUEL SELECTOR TO THE L TANK. THE ENG AGAIN CAME BACK TO 100% PWR. AT THIS POINT WE WERE OVER A GRASS LNDG STRIP JUST S OF ZZZ ARPT AND WE MADE A SLOW CLBING R TURN AT FULL PWR TO GAIN SOME ALT AND TRY TO REMAIN ABOVE THE GRASS FIELD. WE HAD COMPLETED THE TURN TO THE R AND WERE FACING THE ARPT AGAIN WITH THE GRASS FIELD JUST BEHIND OUR R WING. WE THEN EXPERIENCED ENG TROUBLE AGAIN FOR A THIRD TIME. I SWITCHED TANKS AGAIN. NO CHANGE IN PERFORMANCE AND SWITCH ONCE MORE AND STILL NO CHANGE. WE PROCEED TO THE R TO TRY AND SET UP ON THE GRASS STRIP BUT WITHOUT LOSING MORE ALT AND WITH DECREASING AIRSPD IT WAS JUST NOT POSSIBLE. THE GRASS FIELD; JUST TO THE E OF THE GRASS STRIP; WAS LESS OF A TURN TO MAKE AND TO ALLOW FOR SUFFICIENT ALT AND AIRSPD WE LEVELED THE WINGS TO SET UP ON THE GRASS FIELD. WE WERE ABLE TO CLR TREES AND PWR LINES WHERE WE CAME DOWN TO THE FIELD. THE ACFT SET DOWN ON THE FIELD AND WE HELD THE YOKE BACK AS LONG AS POSSIBLE. THE FIELD WAS NOT ROUGH; BUT IT CERTAINLY WAS NOT SMOOTH. THE AIRPLANE BEGAN TO SLOW AND AS WE CAME OVER A CREST IN THE FIELD AND DOWN THE OTHER SIDE AT THE BOTTOM WAS A RUT IN WHICH THE NOSEWHEEL FELL INTO AND SLOWED THE PLANE TREMENDOUSLY. WE EXITED THE AIRPLANE BOTH UNINJURED. WE WERE BOTH SHAKEN UP AND DID NOT INSPECT THE ACFT CLOSELY AT THE TIME. WHAT WE WERE ABLE TO NOTICE AT THE TIME WAS THAT THE NOSE GEAR HAD COLLAPSED AND THE NOSE FELL TO THE GND. IT SLIGHTLY BENT THE PROP AND CRACKED THE ENG COWLING. WE LATER RETURNED TO THE AIRPLANE FOR A CLOSER INSPECTION AND TO TAKE PICTURES FOR THE INSURANCE COMPANY. ACTIONS WE COULD HAVE TAKEN TO PREVENT THIS INCIDENT WOULD HAVE BEEN TO LAND ON THE GRASS STRIP AT THE FIRST SIGN OF ENG ROUGHNESS. IF FUEL STARVATION IS THE OUTCOME; WE COULD HAVE LANDED SOMEWHERE IN BTWN THE ORIGIN AND DEST FOR FUEL. HOWEVER; ACCORDING TO CALCULATIONS THERE SHOULD HAVE BEEN APPROX 45 MINS TO 1 HR OF FUEL REMAINING. AFTER GOING BACK TO THE ACFT AND CHKING EACH TANK; THERE APPEARED TO BE FUEL IN THE TANKS.