Narrative:

While operating den-phx we were descending into phx on the fossl one arrival. We were assigned 280 KTS or greater crossing tonto intersection (srp 010/35). Inside of tonto we were cleared out of 12000' to 10000'. Before reaching 10000' we were cleared to 9000' and then 7000' with a vector to downwind for runway 08. As we descended through 8300' approach control advised us 'adjust your altitude to 9000'' and issued a turn further right. As we complied, the controller advised us of opp direction traffic climbing through 7000' for 8000'. He then asked if we had received our altitude assignment of 9000' and we replied that we had been cleared to 7000'. The remainder of the approach and landing was uneventful. Upon arrival, the captain telephoned approach control to discuss the situation. The controller informed him after reviewing the voice tape that we had acknowledged clearance to 9000' but said nothing about 7000'. He also said that the conflicting traffic had initiated evasive action. We never had visibility contact with the conflicting traffic. Supplemental information from acn 138967. Contributing factors: the altitude alerter is on the first officer's side of the aircraft and he sets it... Flying or not. Also, the location is down out of the normal line of vision instead of on the glare shield accessible by both pilots. Another factor was fatigue. I was on reserve this day and we have a 3 hour minimum show time.

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Original NASA ASRS Text

Title: FLT CREW OF LGT ON ARRIVAL INTO PHX DESCENDS BELOW ASSIGNED ALT OF 9000' BECAUSE THEY BELIEVED THEY WERE CLEARED TO 7000'. ANOTHER ACFT TOOK AVOIDANCE ACTION.

Narrative: WHILE OPERATING DEN-PHX WE WERE DSNDING INTO PHX ON THE FOSSL ONE ARR. WE WERE ASSIGNED 280 KTS OR GREATER XING TONTO INTXN (SRP 010/35). INSIDE OF TONTO WE WERE CLRED OUT OF 12000' TO 10000'. BEFORE REACHING 10000' WE WERE CLRED TO 9000' AND THEN 7000' WITH A VECTOR TO DOWNWIND FOR RWY 08. AS WE DSNDED THROUGH 8300' APCH CTL ADVISED US 'ADJUST YOUR ALT TO 9000'' AND ISSUED A TURN FURTHER RIGHT. AS WE COMPLIED, THE CTLR ADVISED US OF OPP DIRECTION TFC CLBING THROUGH 7000' FOR 8000'. HE THEN ASKED IF WE HAD RECEIVED OUR ALT ASSIGNMENT OF 9000' AND WE REPLIED THAT WE HAD BEEN CLRED TO 7000'. THE REMAINDER OF THE APCH AND LNDG WAS UNEVENTFUL. UPON ARR, THE CAPT TELEPHONED APCH CTL TO DISCUSS THE SITUATION. THE CTLR INFORMED HIM AFTER REVIEWING THE VOICE TAPE THAT WE HAD ACKNOWLEDGED CLRNC TO 9000' BUT SAID NOTHING ABOUT 7000'. HE ALSO SAID THAT THE CONFLICTING TFC HAD INITIATED EVASIVE ACTION. WE NEVER HAD VIS CONTACT WITH THE CONFLICTING TFC. SUPPLEMENTAL INFO FROM ACN 138967. CONTRIBUTING FACTORS: THE ALT ALERTER IS ON THE F/O'S SIDE OF THE ACFT AND HE SETS IT... FLYING OR NOT. ALSO, THE LOCATION IS DOWN OUT OF THE NORMAL LINE OF VISION INSTEAD OF ON THE GLARE SHIELD ACCESSIBLE BY BOTH PLTS. ANOTHER FACTOR WAS FATIGUE. I WAS ON RESERVE THIS DAY AND WE HAVE A 3 HR MINIMUM SHOW TIME.

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.