TCASII INDUCED NMAC LTSS BTWN ACR X AND Y. PLTDEV.

Narrative

THIS IS A RPT ON AN NMAC BTWN ACR X; AN MD80 DEPARTING FROM PDX; AND ACR Y; A DASH-8 INBOUND TO PDX. ACR Y WAS HANDED OFF TO MY SECTOR BY ZSE; AND LEVELED OFF AT HIS ASSIGNED ALT OF 12000 FT. ACR X CAME UP ON FREQ; CLBING TO 9000 FT. THIS IS THE NORMAL PROC FOR DEPARTING TURBOJETS AT PDX. ACR Y WAS DSNDED TO 10000 FT; AND ADVISED OF HIS TFC OPPOSITE DIRECTION CLBING TO 9000 FT; (ACR X; MD80). ACR X WAS ALSO ADVISED OF THE DASH-8 OPPOSITE DIRECTION DSNDING TO 10000 FT. (THIS IS A VERY COMMON; VERY NORMAL; EVERYDAY TYPE SCENARIO HERE AT PDX ON THIS PARTICULAR RWY FLOW). NEITHER PLT SAW THE OTHER ACFT. WHEN ACR X WAS OUT OF 7700 FT; I AGAIN ISSUED TFC TO HIM; AND THE PLT AGAIN SAID THAT HE DID NOT SEE THE OTHER ACFT. ACR Y WAS OUT OF 10500 FT; AND I AGAIN ADVISED HIM OF THE MD80; AND HE SAID HE DID NOT HAVE THE TFC IN SIGHT. I TURNED ACR X JET W ON COURSE AND THEN NOTICED ACR Y ALT WAS 9600 FT AND DSNDING; AND THE PLT OF ACR Y THEN ADVISED HE WAS RESPONDING TO AN RA ON HIS TCASII AND WAS DSNDING TO 9000 FT. ACR X WAS JUST LEVELING OFF AT 9000 FT; 3 MI IN FRONT OF THE DASH-8. I ADVISED ACR Y TO CLB IF HE WAS GOING TO DO ANYTHING; THEN NOTICED THAT BOTH ACFT WERE AT 9100 FT; AND THE TARGETS MERGED ON THE RADAR. BOTH DATA BLOCKS WENT INTO COAST (CST) MODE FOR APPROX 2 SWEEPS; AND THEN APPEARED ONCE AGAIN AS SEPARATE TARGETS. ACR X ALSO ADVISED THAT HE WAS RESPONDING TO A TCASII RA; BUT STANDARD SEPARATION HAD ALREADY BEEN LOST. NEITHER ACFT'S CREW SAW THE OTHER; THOUGH THE WX WAS CLR; WITH 40 MI VISIBILITY. THE PLT OF ACR X CALLED WHEN HE ARRIVED IN SEA; AND SAID THAT THE PAX; HOWEVER; GOT A GREAT VIEW OF THE OTHER ACFT. IT SHOULD BE NOTED THAT THIS WAS NOT A PLT ERROR; NOR A CTLR ERROR. THIS WASN'T EVEN AN EQUIP MALFUNCTION. THE TCASII WORKED EXACTLY AS IT WAS DESIGNED TO. THIS THING IS SOMEWHAT LIKE THE 'O' RINGS IN THE SPACE SHUTTLE -- THAT IS; A LOT OF PEOPLE KNOW THAT THERE IS SOMETHING WRONG WITH THIS; BUT NOBODY WANTS TO STAND UP AND SAY SO.