AN ACR LGT HAD TO MAKE A HIGHSPD ABORT TO AVOID AN SMA THAT DID NOT FOLLOW ITS TKOF INSTRUCTIONS.

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WE WERE CLRED TO POS AND HOLD ON RWY 09L AT MIA; AND WHILE WE HELD IN POS 2 SMALL ACFT WERE CLRED TO TKOF IN FRONT OF US FROM A DOWNFIELD TXWY. THE SECOND AIRPLANE; AN SMA; BECAME AIRBORNE AND BEGAN A SLOW CLB. WE WERE THEN CLRED FOR 'IMMEDIATE TKOF' DUE LNDG TFC. WE HAD THE SMA IN SIGHT AND; ALTHOUGH HE HAD NOT STARTED TURNING; HE HAD BEEN CLRED ON A 060 DEG HDG. WITH OUR ACFT ACCELERATING RAPIDLY AND GOING THROUGH 80 KIAS; THE SMA HAD STARTED HIS TURN AND THE DEP PATH WAS CLR. AT THAT TIME; HOWEVER; THE SMA LEVELED HIS WINGS AND WITH A L XWIND WAS SLOWLY BEING BLOWN BACK TO THE RWY CTRLINE. IN JUST A COUPLE OF SECONDS WE REACHED OUR VR SPD OF 141 KIAS AND BEGAN ROTATION TO TKOF; BUT THE SMA WAS NOW VERY CLOSE TO THE EXTENDED CTRLINE OF RWY 9L AND WAS BOUNCING DUE TO TURB OVER THE FIELD; HORIZ FLT TRACK WAS UNCERTAIN. THE NOSE WHEEL WAS OFF THE GND AND THE MAINS WERE BECOMING AIRBORNE BUT THE SMA WAS NOW LESS THAN 2000 FT DOWNTRACK AND ONLY 200 FT IN ALT; MOVING TOWARDS THE CTRLINE; AN ABORT WAS ESSENTIAL TO AVOID A POSSIBLE COLLISION; OR AT THE LEAST; A NEAR MISS. THE ABORT WAS INITIATED AT APPROX 143 KIAS WITH THE ACFT JUST BECOMING AIRBORNE. RWY 9L AT MIA IS 10500 LONG AND BECAUSE OF THE LONG RWY OUR ACFT WAS STOPPED WITH APPROX 2000 FT REMAINING. I FEEL THIS VERY DANGEROUS SIT CAME ABOUT BECAUSE OF A LCL CTLR TRYING TO DO TOO MUCH. TFC VOLUME IN MIA THIS TIME DURING THE DAY IS HVY AND EVERYONE TRIES TO MAINTAIN A 'CAN DO' ATTITUDE. FACTORS THAT CONTRIBUTED TO THIS OCCURRENCE WERE: THE TREMENDOUS DIFFERENCE IN PERFORMANCE/AIRSPD BTWN THE SMA AND AN LGT. JUST PRIOR TO ABORT OUR CLOSURE ON THE SMA WAS APPROX 50 KTS. THE FAILURE OF THE SMA PLT TO EXECUTE THE 060 DEG TURN. THE SMA ASSOCIATION HAS A VERY STRONG LOBBY IN THIS COUNTRY AND THEY FIGHT VERY HARD TO HAVE THE RIGHT TO USE THESE MAJOR ARPTS. THIS INCIDENT DEMONSTRATES WHY THIS IS A PROB FOR PLTS AND CTLRS ALIKE. AS FOR MY PART; I ASSUMED THAT BOTH THE SMA PLT AND THE CTLR WERE DOING THEIR JOBS AS EVERYONE ALMOST ALWAYS DOES; I ALMOST HELD ON TO THIS BELIEF TOO LONG.