A B737-300 FLC HAVE A POTENTIAL CONFLICT WITH AN UNKNOWN ACFT FLYING AT THE BASE OF THE CLASS B AIRSPACE 12 NM SW OF CLT.

Narrative

CLT APCH; LEFT DOWNWIND RWY 36L IN TURN TO BASE LEG. TURNING TO HDG 090 FT ALT 3600 FT ASSIGNED BY ATC. ABOUT THE 210 DEGREE RADIAL OF THE CLT VOR. ABOUT THE 12 DME POINT. 2 TO 3 NM'S N OF ROCK HILL/YORK CO ARPT. VFR CONDITIONS. DURING L TURN TO 090 DEGREEE HDG; TFC APPEARED ON TCAS II SCREEN AT ABOUT THE 11 O'CLOCK POS. ROTATING CLOCKWISE ON THE SCREEN TO THE 2 O'CLOCK POS AS WE ROLLED OUT. OUR AIRSPEED WAS 170 KTS ASSIGNED. THIS CAUSED A HIGH ANGLE OF ATTACK IN THE TURN CAUSING THE VIEW OUT THE FORWARD WINDOW TO BE SOMEWHAT BLOCKED. DID NOT SEE THE OTHER ACFT UNTIL WE ROLLED OUT AS IT PASSED OFF OUR 3 O'CLOCK POS. TFC APPEARED TO BE HDG W BOUND. -300 FT BELOW. TFC WAS JUST INSIDE THE 2.5 NM RING ON TCASII SCREEN WITH 5 NM RANGE SELECTED. WE RECEIVED ONLY AN RA. NEVER RECEIVED A TA. RA COMMANDED A CLB. WE CLBED 200 FT (3800 MSL) BEFORE 'CLR OF CONFLICT' OCCURRED. TCASII TFC WAS SHOWING -300 FT ON SCREEN. NOTE: THE FLOOR OF CLASS 'B' AIRSPACE IN CLT IN THIS AREA IS 3600 FT. CLT APCH ROUTINELY PUTS US AT 3600 FT WHEN BEING VECTORED FOR RWY 36L. IF VFR TFC IS FLYING UNDER THE CLASS 'B' AT 3500 FT THERE IS NO VERTICAL SEPARATION. WE HAVE NO PROTECTION FROM VFR TFC. CLASS 'B' AIRSPACE NEEDS TO BE LOWERED FARTHER OUT FROM ARPT. WHEN TFC INCREASES SO DOES THE LENGTH OF THE FINAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: CAPT STATED THAT THE CTLR DID ISSUE A TA; BUT FAR TOO LATE TO BE OF ANY USE. WELL AFTER THE TCASII HAD ISSUED THE RA. RPTR TURNED IN A RPT TO THE COMPANY; BUT DID NOT HOLD OUT MUCH HOPE FOR ANY RESOLUTION FROM THAT SOURCE. THE CAPT STATED THAT NEXT TIME INTO CLT A CALL WILL BE MADE TO THE TRACON SUPVR REGARDING THIS ISSUE. CAPT RECOMMENDS THAT CLT APCH CTL SHOULD RAISE THE ALT IN THAT AREA TO 4000 FT VS THE NOW USED 3600 FT.