Narrative:

Conditions: IMC, night, light to moderate turbulence. Air carrier was on the fossl 2 arrival into phx. We were given a tonto crossing restr of 12000 ft 250 KTS. ATC then asked us to increase speed to 280 KTS. I acknowledged and the first officer increased speed to 280 KTS. Soon after we were given a clearance to '...descend and maintain 7000 ft.' as I acknowledged this clearance, my first officer set 7000 ft in the altitude alert window and began the descent. Shortly after leaving 1200 ft we got a TCASII alert 'traffic, traffic, reduce descent.' I told my first officer to comply with TCASII, and I noted the traffic on the TCASII screen at 12 O'clock and -700 ft. I instructed my first officer to stop descent until we were clear of the traffic. We were then given another RA by TCASII 'climb, climb.' without hesitation and simultaneously I advanced the thrust levers, pulled back on the yoke and commanded the first officer to continue the climb. Due to radio congestion we were about 12400 ft. When I was able to advise ATC that we were deviating from our clearance due to a TCASII RA, ATC replied with 'deviate as necessary, when able maintain 12000 ft.' as the TCASII had given us the 'clear of conflict' the first officer descended to 12000 ft. When radio congestion permitted, I questioned the controller about this incident, and to our amazement and horror we were told that we were never given a descent clearance. I told him that we had and that I had repeated it back. ATC then advised us that he hadn't received any readback from us. I replied 'thank god for TCASII.' my first officer said (to me) that this might be a good occasion for a NASA report. I agreed. In conclusion, I would like to say that regardless of fault, TCASII saved our bacon.

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Original NASA ASRS Text

Title: RPTR RESPONDS TO RA AFTER HAVING ALLEGEDLY DSNDED WITHOUT A CLRNC.

Narrative: CONDITIONS: IMC, NIGHT, LIGHT TO MODERATE TURB. ACR WAS ON THE FOSSL 2 ARR INTO PHX. WE WERE GIVEN A TONTO XING RESTR OF 12000 FT 250 KTS. ATC THEN ASKED US TO INCREASE SPD TO 280 KTS. I ACKNOWLEDGED AND THE FO INCREASED SPD TO 280 KTS. SOON AFTER WE WERE GIVEN A CLRNC TO '...DSND AND MAINTAIN 7000 FT.' AS I ACKNOWLEDGED THIS CLRNC, MY FO SET 7000 FT IN THE ALT ALERT WINDOW AND BEGAN THE DSCNT. SHORTLY AFTER LEAVING 1200 FT WE GOT A TCASII ALERT 'TFC, TFC, REDUCE DSCNT.' I TOLD MY FO TO COMPLY WITH TCASII, AND I NOTED THE TFC ON THE TCASII SCREEN AT 12 O'CLOCK AND -700 FT. I INSTRUCTED MY FO TO STOP DSCNT UNTIL WE WERE CLR OF THE TFC. WE WERE THEN GIVEN ANOTHER RA BY TCASII 'CLB, CLB.' WITHOUT HESITATION AND SIMULTANEOUSLY I ADVANCED THE THRUST LEVERS, PULLED BACK ON THE YOKE AND COMMANDED THE FO TO CONTINUE THE CLB. DUE TO RADIO CONGESTION WE WERE ABOUT 12400 FT. WHEN I WAS ABLE TO ADVISE ATC THAT WE WERE DEVIATING FROM OUR CLRNC DUE TO A TCASII RA, ATC REPLIED WITH 'DEVIATE AS NECESSARY, WHEN ABLE MAINTAIN 12000 FT.' AS THE TCASII HAD GIVEN US THE 'CLR OF CONFLICT' THE FO DSNDED TO 12000 FT. WHEN RADIO CONGESTION PERMITTED, I QUESTIONED THE CTLR ABOUT THIS INCIDENT, AND TO OUR AMAZEMENT AND HORROR WE WERE TOLD THAT WE WERE NEVER GIVEN A DSCNT CLRNC. I TOLD HIM THAT WE HAD AND THAT I HAD REPEATED IT BACK. ATC THEN ADVISED US THAT HE HADN'T RECEIVED ANY READBACK FROM US. I REPLIED 'THANK GOD FOR TCASII.' MY FO SAID (TO ME) THAT THIS MIGHT BE A GOOD OCCASION FOR A NASA RPT. I AGREED. IN CONCLUSION, I WOULD LIKE TO SAY THAT REGARDLESS OF FAULT, TCASII SAVED OUR BACON.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.