PLT OF RA390 RPTS A CLOSE ENCOUNTER WITH AN UNIDENTED AND UNAUTH SAILPLANE JUST BELOW HIS FLT PATH IN CLASS C AIRSPACE ON APCH TO SAT.

Narrative

OPERATING IFR IN VMC CONDITIONS; LNDG SAT. I HAD JUST BEEN CLRED FOR VISUAL APCH RWY 12R AT SAT. DSNDING THROUGH 3800 FT MSL; I SAW A GLIDER IN A STEEP TURN PASS JUST BELOW ACFT. ALTHOUGH CLOSE; IT WAS OBVIOUS AT THIS POINT; THAT WE WOULD MISS. AT ANY RATE; IT WAS TOO LATE TO TAKE EVASIVE ACTION. ATC HAD NOT CALLED TFC. GLIDER PLT CAME ON FREQ ABOUT 1 MIN LATER AND QUERIED ATC. APPARENTLY; THE GLIDER PLT THOUGHT HE HAD AN OPERATING XPONDER. ATC SAID THEY WERE NOT 'PAINTING' HIM. ATC ALSO ADVISED GLIDER PLT THAT AT THAT ALT/POS HE WAS RIGHT IN THE ARR PATH FOR RWY 12R; AND HE NEEDED TO BE TALKING TO THEM. WE WERE CLOSE TO THE BOUNDARY OF THE CLASS C AIRSPACE WHEN THE INCIDENT OCCURRED -- EITHER JUST INSIDE OR JUST OUTSIDE. JUST BEFORE EVENT OCCURRED; ATC HAD INSTRUCTED ME TO 'MAINTAIN PRESENT SPD;' AND I WAS OPERATING AT 200 KIAS. AT THIS SPD; CLOSURE RATE WITH GLIDER WAS PROBABLY AROUND 320 FPS. THIS PROVIDES VERY LITTLE REACTION TIME. LCL GLIDER TFC SHOULD BE KEPT CLR OF HIGH-SPD JET ARRS.