SMA HAS ALTERNATOR LIGHT ACTIVATE; TURNS OFF MASTER. HAS ENG FAILURE; FORCED LNDG.

Narrative

WE TOOK OFF FROM MARRON; IA; FOR CLARINDA; IA. NO FLT PLAN WAS USED AS WE USE VFR FLT FOLLOWING WHEN NOT IFR. WE IMMEDIATELY ENTERED CEDAR RAPIDS AIRSPACE CLBING TO 6500 FT WHEN A FEW MINS LATER OUR ALTERNATOR LIGHT WENT ON INDICATING WE WERE ON BATTERY PWR ONLY. I WAITED UNTIL WE WERE ALMOST OUT OF CEDAR RAPIDS AIRSPACE WHEN I INFORMED ATC THAT I WOULD LIKE TO CANCEL SVCS AS WE HAD ELECTRICAL PROBS. THIS DID NOT CONSTITUTE AN EMER IN MY MIND AS WE HAD GOOD VFR AND OUR FLT PATH KEPT US OUT OF ANY CTLED AIRSPACE. I TURNED OFF THE MASTER TO PREVENT ANY POSSIBLE DRAIN ON THE BATTERY SO THAT WE COULD LOWER GEAR; FLAPS; ETC WHEN WE GOT TO OUR DEST ARPT. IT WAS STILL NOT DARK AT THIS TIME. WE CONTINUED ON FOR 20 MINS TILL WE HAD A CATASTROPHIC ENG FAILURE. I TURNED ON ALL ELECTRICAL SYS AND MADE AN EMER LNDG IN A FIELD NEAR INDIANOLA; IA; WHICH WE SURVIVED. THE FAA WANTS TO TAKE ACTION AGAINST ME BECAUSE I TURNED NAV LIGHTS OFF AND XPONDER OFF. I COULD HAVE LANDED AT CEDAR RAPIDS ARPT BUT I THOUGHT IT MORE LOGICAL TO PROCEED TO CLARINDA AS MY ELECTRICAL PROBS WERE NOT AN EMER IN MY MIND.