LGT TCASII RA NON RESPONSE HAD NMAC LTSS FROM SMA. SYS ERROR.

Narrative

I WAS OBSERVING COCKPIT OPS (UNDER THE SF-160 PROGRAM) FROM THE JUMP SEAT OF AN LGT. THE CAPT WAS LINED UP ON THE LOC AND THE RWY WAS IN SIGHT. WE WERE APPROX 3-4 MI FINAL AND 1300 FT WHEN THE TCASII ANNOUNCED 'TFC.' I OBSERVED A TARGET ON THE DISPLAY AT 1 O'CLOCK; 2 MI; CONVERGING; INDICATING 500 FT BELOW US (WE WERE DSNDING ON THE GS). THE CAPT; FO; AND I ALL SEARCHED FOR THE TFC; BUT COULDN'T SEE IT. VERY SOON AFTER; TCASII ANNOUNCED A 'CLB' RA. THE FO LOOKED QUICKLY AT THE DISPLAY AND THEN TO THE CAPT AND SAID; 'YOU'D BETTER CLB.' THE CAPT SAID 'THERE'S NOBODY OUT THERE.' I SAW ON THE DISPLAY THAT THE TARGET WAS NOW 12 O'CLOCK; IMMEDIATELY IN FRONT OF US; SHOWING AT OUR ALT. THE FO SAID TO THE CAPT; 'YOU'VE GOT TO FOLLOW IT!' (THE RA.) THE CAPT RESTATED THAT THERE WAS NO TFC AND CONTINUED ON THE APCH. WHEN TCASII ANNOUNCED THAT THE CONFLICT HAD PASSED; THE VISIBLY SHAKEN FO CURSED LOUDLY; '(XXXX) THAT SCARES THE (XXXX) OUT OF ME!' LOOKING AT THE DISPLAY; THE TARGET WAS NOW BEHIND US AND SEVERAL HUNDRED FT BELOW; LEADING ME TO BELIEVE THAT THE OTHER PLT MAY HAVE TAKEN EVASIVE ACTION. WHEN THE FO INSISTED THAT THERE HAD BEEN TFC; THE CAPT TOLD THE FO TO ASK THE CTLR IF HE HAD ANY TFC ON THE FINAL APCH COURSE. UP TO THIS POINT; THE TWR HADN'T ISSUED US ANYTHING BUT A LNDG CLRNC. THE CTLR TOLD THE CREW THAT HE DID HAVE TFC (AN SMA) ON FINAL; BUT THAT HE (THE CTLR) HAD BOTH OF US IN SIGHT. THE CTLR WENT ON TO APOLOGIZE; SAYING THAT HE SHOULD HAVE TOLD US OF THE TFC; BUT THAT HE GOT BUSY DOING SOMETHING ELSE. WE FLARED; TOUCHED DOWN; AND THE CAPT GOT ON THE RADIO AS WE ROLLED OUT AND (VERY PROFESSIONALLY) GAVE THE CTLR AN EARFUL. CAPT FELT THAT FOLLOWING A TCASII RA WAS HIS OPTION BASED ON WHETHER OR NOT HE BELIEVED THERE WAS TFC. THE FO DISAGREED. ALL 3 OF US DID AGREE; HOWEVER; THAT THE LCL CTLR SHOULD HAVE ISSUED TFC OR; MORE APPROPRIATELY; KEPT THE TFC AWAY FROM THE FINAL APCH COURSE. I BELIEVE THAT I WITNESSED A 'SYS' FAILURE. EVERY BUILT-IN SAFEGUARD FAILED. ATC KNEW OF THE TFC; WAS IN CONTACT WITH THE TFC; BUT WAS DISTRACTED AND DIDN'T ISSUE TFC TO EITHER ACFT. TCASII CALLED THE TFC AND OFFERED AN RA; BUT BECAUSE THE CAPT COULDN'T SEE IT; IT WASN'T THERE. AND THE FINAL XCHK; COCKPIT RESOURCE MGMNT; BROKE DOWN AT A CRITICAL TIME.