DOOR POPS OPEN ON SMT; PLT DIVERTS TO NEAREST ARPT AND LANDS.

Narrative

WE WERE CRUISING AT 7000 FT AND TALKING TO ZMA WHEN THE MAIN CABIN DOOR POPPED OPEN; CAUSING A GREAT DEAL OF NOISE AND PANIC WITH MY 2 PAXS. I ADDED FULL PWR BECAUSE THE ACFT WAS DSNDING AT APPROX 200 FPM. I CALLED CTR TOLD THEM I HAD A DOOR COME OPEN AND WANTED TO RETURN TO TPA. AFTER SEVERAL SECONDS; ZMA TOLD ME I WAS CLRED DIRECT TPA TO MAINTAIN 7000 FT BUT I HAD COME DOWN TO 6500 FT BY NO CHOICE OF MINE. ZMA TOLD ME TO CONTACT TPA APCH; WHICH I DID IMMEDIATELY. WHEN I DID CONTACT TPA; THEY TOLD ME I HAD VIOLATED THE TCA; BUT I TOLD THEM I HAD BEEN CLRED TO TPA BY ZMA. I ALSO TOLD TPA THAT I HAD A PROBLEM WITH MY DOOR BEING OPEN AND ASKED FOR VECTORS TO LAKELAND; THE CLOSEST ARPT AT THE TIME. I RECEIVED VECTORS; AND HEADED FOR LAKELAND. I ASKED FOR A STRAIGHT IN TO RWY 5 AT LAL; AND TPA SAID IT WAS APPROVED AND TO CONTACT LAL TWR. I DID SO; BUT WAS TOLD I WOULD HAVE TO DECLARE AN EMER TO GET 5; BECAUSE THE ACTIVE WAS 27 AT THE TIME. I TOLD THEM; IF I HAD TO; I HAD TO. THE ACFT WAS STILL NOT FLYING VERY WELL; AND THE ATTEMPTS TO CLOSE THE DOOR WAS UNSUCCESSFUL. WE LANDED ON 5 WITHOUT FURTHER INCIDENT. THE ONLY THING THAT I WOULD DO DIFFERENTLY; IS TRIPLE CHK THE DOOR WAS CLOSED PROPERLY AND TO DECLARE AN EMER SOONER IF I THOUGHT THERE WAS A REAL PROBLEM; WHICH THERE WAS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. RPTR IDENTED ACFT AS A TWIN ENG SMT. HE SAID THAT THE DOOR WAS INSPECTED AFTER THE INCIDENT AND FOUND TO BE IN GOOD CONDITION; NOTHING WAS WRONG WITH IT. HE COULD MAINTAIN ALT WITH FULL PWR BUT THE AIRPLANE WALLOWED; ROLLED AND YAWED. AS HE SLOWED DOWN TO LAND; THE ACFT BECAME MORE STABLE. HE SAID THAT THERE WAS NO NOISE ABATEMENT CONCERN IN LAL; JUST THAT THE TWR INSISTED HE DECLARE AN EMER BEFORE HE COULD BE ASSIGNED HIS CHOICE OF RWY 5. GOOD SVC? REGARDING THE DECLARATION OF AN EMER; NO ONE HAS CONTACTED HIM FOR ANY INFO.