CAPT OF MLG ACR ACFT DSNDED BELOW ASSIGNED PROFILE ARR CLRNC.

Narrative

WE WERE PROCEEDING RNAV DIRECT TO DRAKO AND CLRED TO CROSS DRAKO AT 17000 AND 250 KTS. AFTER DRAKO WE WERE CLRED TO 11000 AND WERE 'AS FILED' DIRECT TO DENVER. WE HAD NOT BEEN CLRED FOR THE PROFILE DSCNT. WE WERE SWITCHED TO APCH CTL -- THE CAPT SAID 'ACR FLT NUMBER WITH YOU.' I FEEL HE SHOULD HAVE SAID 'DSNDING TO 11000' IN WHICH CASE THERE MAY NOT HAVE BEEN THIS INCIDENT. THE CTLR SEEMED TOTALLY UNAWARE OF US AND ASKED; 'WHO IS THAT? WHERE ARE YOU? ARE YOU ON THE PROFILE?' I THINK THE CAPT SAID WHO WE WERE AND THAT WE WERE ON THE PROFILE -- MEANING ROUTING; NOT ALTS. I THINK THIS LED THE CTLR TO BELIEVE WE WERE ONLY DSNDING TO THE PROFILE ALT OF 13000. WE THEN GOT A TCASII RA DIRECTING US TO CLB (AT ABOUT 13200 FT). WE INFORMED THE CTLR AND STARTED A CLB. THE CTLR POINTED OUT 2 O'CLOCK TFC AT 12000 FT. WE RECEIVED A TCASII 'CLR OF TFC' AND CONTINUED OUR DSCNT. AT ABOUT 12700 FT I ASKED THE CAPT TO CHK THAT WE WERE CLRED TO 11000 FT AS I NOW REALIZED THAT WOULD HAVE TAKEN US THROUGH THE 12000 FT ALT OF THE TFC. THE CTLR SAID 'NO; YOU WERE ONLY CLRED TO 13000 FT BUT GO AHEAD NOW AND DSND TO 11000 FT.' THE FLT PROCEEDED NORMALLY. I BELIEVE WE WERE ORIGINALLY CLRED TO 11000 FT. FOR SOME REASON; APCH CTL WAS NOT INFORMED OF THIS. LACK OF CONCISE RADIO PHRASEOLOGY LED THE CTLR TO BELIEVE WE WERE 'ON' I.E.; 'CLRED FOR THE PROFILE' AND THEREFORE ONLY DSNDING TO 13000. HE THEN CLRED TFC BELOW US TO CLB TO 12000 FT RESULTING IN A CONFLICT. THE APCH CTL WAS CONFUSED ABOUT OUR CLRNC. WE SHOULD HAVE RPTED IN 'DSNDING TO 11000 FT.' 2 INSTANCES OF BAD COM LED TO A POTENTIAL TFC CONFLICT. IN THIS CASE; TCASII ALERTED US TO THE PROBLEM.