RPTR CLAIMS THEY RECEIVED A GPWS WHILE DSNDING FROM 5000 FT TO 3800 FT ON A VECTOR HDG TO INTERCEPT THE LOC FOR RWY 27.

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FLT EXPERIENCED A GPWS ALERT. THE ACFT WAS ON A BASE LEG DSNDING FROM 5000 FT TO 3800 FT. THE CTLR HAD ISSUED A VECTOR OF 180 DEGS FOR A DOGLEG AND ANOTHER VECTOR TO INTERCEPT THE LOC 27 APCH TO SAN. THE GPWS ALERT SOUNDED; THE CAPT DISCONNECTED AUTOPLT AND CLBED APPROX 1500 FT OR UNTIL THE GPWS WARNING CEASED. APCH AND LNDG IN SAN WERE NORMAL. DURING TURNAROUND; THE CAPT TALKED WITH THE SUPVR AND HE INFORMED ME THIS HAPPENS ALL THE TIME AND HAS OCCURRED ROUTINELY FOR MANY YRS. I ASKED HIM IF HE WAS AWARE OF OUR PROCS FOR A GPWS ALERT. HE INDICATED HE WAS AWARE OF OUR PROCS. I TOLD HIM IT IS VERY FRIGHTENING FOR THE CREW AND PAX BECAUSE IT'S A VERY AGGRESSIVE MANEUVER. THE SUPVR INDICATED THE POINT OF CONCERN IS MOUNT SAN MIGUEL LOCATED 1 1/2 - 2 MI N OF SWATT INTXN ON THE LOC 27 APCH TO SAN. HE TOLD ME TO CONTACT OUR SAFETY FOLKS TO CONTACT THEIR SAFETY FOLKS AND TOLD ME A SOLUTION COULD BE WORKED OUT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR LEARNED SEVERAL FACTS FROM A CALL TO A FACILITY PERSON. THE GPWS WARNINGS OCCUR A COUPLE TIMES A DAY. THE FACILITY IS REQUIRED TO LOG ALL GPWS RPTS. THE FACILITY WILL OCCASIONALLY GET A LOW ALT ALERT ON AN ACFT IN THIS AREA. THE GPWS WARNINGS GENERALLY OCCUR WHEN AN ACFT IS ON A 4 MI BASE LEG-TO- FINAL APCH AND IS BELIEVED TO BE CAUSED BY THE ANGLE OF DSCNT WHEN DSNDING FROM 5000 FT TO 3800 FT. FACILITY PERSON CLAIMS IT DOES OCCUR ON OCCASION WITH ACFT DSNDING INBOUND FROM THE N AND FROM THE E. THIS PERSON INDICATED THERE HAVE BEEN NO RECENT CHANGES TO THE MVA PROCS FOR THIS AREA. FACILITY PERSON DID NOT KNOW IF THE GPWS RPTS INVOLVED MD80 TYPE ACFT.