TCASII ALERT PLTDEV.

Narrative

ACR X SWBOUND AT FL260. TA ISSUED AND ACFT SWITCHED TO 133.9. AS I WAS ABOUT TO CALL OTHER TFC WHEN ACR Y AT FL270 SAID SHE HAD TCASII ALERT AND WAS ACTIVATING. (HOWEVER I DON'T KNOW IF IT'S UP OR DOWN OR WHY). ASKED AGAIN AND SHE SAID DSCNT (FROM ACR Z WHO IS DSNDING TO FL280) I SAID I WOULDN'T DO THAT BECAUSE THERE'S A 26 OFF YOUR L SIDE. SHE THEN SAID SHE WAS CLBING BACK UP. ACR X WHO I SWITCHED; ACTIVATED TCASII AND DSNDED. TFC NOSE TO NOSE 400 FT 3 1/2 MI AT FL260. SUPPLEMENTAL INFO FROM ACN 288612: CRUISING AT FL260 IN VICINITY OF PXT HAD TA POP UP 5 MI AHEAD AT 12 O'CLOCK SHOWING 300 FT ABOVE OUR ALT. TA QUICKLY TURNED INTO RA WITH DSND ANNUNCIATION. IMMEDIATELY TURNED OFF AUTOPLT AND BEGAN DSCNT. AT FL255 FT GOT THE MONITOR VERT SPD FOLLOWED BY CLR OF CONFLICT. I QUICKLY BUT SMOOTHLY RETURNED TO FL260. WE DID ADVISE CTLR AS SOON AS WE LEFT FL260 AND HIS RESPONSE WAS DO WHAT YOU HAVE TO DO -- AND THAT HE WAS NOT WORKING THAT INTRUDER ACFT. THIS WAS A TEXTBOOK EXAMPLE OF THE VALUE OF TCASII. COUNT ME AMONG THE BELIEVERS.