B737-500 FLT CREW HAS CONCERN WITH ACFT SEPARATION DURING APCH TO MYR.

Narrative

AFTER BEING CLRED FOR A VISUAL APCH TO RWY 18 AND ONLY 3.5 NM FROM RWY END; TWR CLRED US TO LAND '#2 BEHIND A C130 ON R DOWNWIND.' WE WERE INDICATING 150 KTS PLANNING TO SLOW TO FINAL APCH SPD AFTER BEING HELD; AT A HIGHER ALT LONGER THAN PRACTICAL FOR A NORMAL APCH TO LNDG. WHEN I LOCATED THE C130; IN MY OPINION; WE WERE MUCH TOO CLOSE TO CONTINUE. I FELT THAT WHEN THE C130 WERE TO TURN ONTO FINAL; THAT WE BE ONLY 1/4 MI APART AT THE MOST. I INFORMED TWR WE WOULD REQUIRE A 360 DEG TURN FOR SEPARATION FROM THE C130. TWR RESPONDED; 'NO YOU DON'T' IN AN INDIGNANT TONE OF VOICE; FOLLOWED BY 'CONTINUE.' TWR DID NOT KNOW OUR AIRSPD AND WE DID NOT KNOW HIS PLAN OF ACTION. I SLOWED THE ACFT TO FINAL APCH SPD WITH FULL LNDG FLAPS. THE C130 MADE A 'SHORT APCH' AND THEN A TOUCH-AND-GO. AT NO TIME WERE WE EVER INFORMED OF THE INTENTIONS OF THE C130; OR OF THE TWR CTLR. WE LANDED SAFELY AFTER SLOWING SUBSTANTIALLY. HAD WE BEEN IN A HEAVIER ACFT OR IN A B737-800/B737-900; THERE IS NO POSSIBLE WAY WE WOULD HAVE BEEN ABLE TO SLOW ENOUGH TO PROVIDE ADEQUATE SEPARATION BTWN US AND THE C130. THE TWR CTLR SEEMED CONTENT WITH TELLING US HOW TO FLY OUR ACFT; WHILE NOT KEEPING US IN THE LOOP AS TO HIS INTENTIONS.