ATR42 WAS ON ILS VISUAL APCH RWY 9L AT MIA. A VECTORED DC10 OVERSHOT THE ILS COURSE TO RWY 9R AND CAME WITHIN 200 FT VERTLY OF THE ATR42 ON ILS RWY 9L. THE ATR42'S TCASII GAVE AN RA OF CLB. THAT WOULD HAVE CAUSED A COLLISION. PIC OF ATR42 DOVE TO ESCAPE THE DC10.

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AT APPROX AM40 THIS MORNING WE WERE ON THE RWY 9L LOC APPROX 10 MI OUT; CLRED FOR A VISUAL APCH. A DC10 WAS CLRED FOR RWY 9R; HE OVERSHOT AND WAS COMING AT US. THE TCASII SHOWED HIS ALT TO BE +200 FT; WE WERE DSNDING THROUGH APPROX 2800 FT MSL. I CANNOT RECALL IF WE EVER GOT A TA ON HIM BUT AS HE APCHED WE RECEIVED A CLB RA. THERE IS NO DOUBT IN MY MIND THAT HAD WE OBEYED A COLLISION WOULD HAVE RESULTED. I DOVE AND ACCELERATED TO 240 KTS; THE ACFT PASSED OVER THE TOP OF US AND THE TWR TURNED HIM AWAY TO THE NW. HIS ALT SHOWED +200 FT AND WE WERE IN A DSCNT FOLLOWING THE GS. THE TCASII SHOULD HAVE COMMANDED A DSCNT. HAD IT BEEN IMC WE WOULD HAVE CLBED INTO HIM. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR THOUGHT THAT THE DC10 BELONGED TO A FOREIGN CARRIER WHICH MAY NOT HAVE HAD A TCASII SYS ON BOARD. HIS TCASII DIDN'T ISSUE A 'TA' PRIOR TO THE RA. AFTER HE SAW THE DC10 HE DOVE TO 1500 FT MSL; WITH THE TCASII RA THEN AGREEING WITH HIS DSCNT PROFILE. THE DC10 WAS NOT DSNDING BUT HAD OVERSHOT THE ILS FOR RWY 9R. THE RPTR FILED A RPT WITH HIS SAFETY REPRESENTATIVES AT THE UNION BUT DOESN'T KNOW WHAT THEY FOUND OUT. THEY WERE ASKING FOR TWR TAPE TO BE PULLED. HE BELIEVES THAT HIS TCASII HAD THE LATEST SOFTWARE. THE MANUFACTURER WAS CONTACTED AND DID NOT HAVE AN ANSWER TO WHAT THE PROB WAS. THE RPTR SAID AN SF340 HAD A SIMILAR EXPERIENCE WITH THE DIAGNOSTIC CHK SHOWING NO PROBS. HE WAS TOLD BY THE TWR CTLR THAT A WK PRIOR TO THIS EVENT; A SIMILAR TCASII RA FAULT HAD OCCURRED AT FT LAUDERDALE.