VFR MOONEY M20K PLT TRAVERSING JUST OUTSIDE OF THE MIA CLASS B AIRSPACE HAS CLOSE ENCOUNTER WITH A BEECH 1900 GOING TO MIA.

Narrative

THIS WAS A SHORT REPOSITIONING FLT FROM TMB TO FLL. BECAUSE OF TSTMS TO THE E OF TMB; I ELECTED TO DEPART TMB TO THE NW AND THEN TO THE W OF THE MIAMI CLASS B AIRSPACE AT 1500 FT. I WAS GIVING THE 10 MI RING AROUND MIA ABOUT A 1.5 MI BUFFER (USING A GPS WITH A CURRENT DATABASE). THE BASE IN THE CLASS B AIRSPACE IN THAT AREA IS 3000 FT. I LOOK OVER TO MY R AND SAW A BE1900 750-1000 FT TO MY R (HE HAD COME UP FROM BEHIND). HE BEGAN A CLB AND I DSNDED. HE THEN TURNED R AND CROSSED ABOVE ME INBOUND TO MIAMI (I WOULD GUESS). THIS WAS PRETTY CLOSE. I AM WORRIED THAT I MIGHT HAVE BEEN TOO CLOSE TO THE CLASS B AIRSPACE EVEN THOUGH THE GPS SHOWED I WAS 1.5 MI W OF THE 1500 FT FLOOR. I CALLED UP FLL ABOUT 5 MINS LATER FOR FLT FOLLOWING INTO FLL AND LANDED UNEVENTFULLY. IN LOOKING AT THE CHART LATER; IT LOOKS LIKE I WAS W OF A CANAL THAT WAS ALSO W OF THE 10 MI RING. LOOKING AT THE REG; THERE IS NO REQUIREMENT FOR ATC TO HAVE THE BE1900 INSIDE THE CLASS B AIRSPACE ALTHOUGH THE LOW CEILING AND CONVECTIVE ACTIVITY MAY HAVE PUSHED HIM DOWN TO 1500 FT SOONER.