Narrative:

Air carrier X flight from pit to dtw feb/mon/98. Captain flying and being vectored by ATC to join the cetus arrival a few mi northwest of the dryer VOR. Captain heard instructions by ATC to join the arrival and descend so as to reach the cetus intersection by 10000 ft. First officer was handling the radios but did not hear the clearance, so the captain repeated it to him and the first officer acknowledged to ATC that air carrier X would cross the cetus intersection at 10000 ft. As the captain executed the descent, he could see possible conflicting air carrier Y traffic on the TCASII approaching 5-8 mi in front of him, so he leveled off above the traffic, never reaching 10000 ft. The TCASII issued a TA/RA anyway, so the captain executed the appropriate response climbing to and leveling at 12000 ft. A frequency change from ATC to approach control was issued just as this was happening. Although 12000 ft is the altitude normally assigned according to the depiction on the cetus arrival, there was absolutely no question in the captain's mind that 10000 ft was the altitude assigned and acknowledged back to the ATC controller issuing the clearance.

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Original NASA ASRS Text

Title: AN ACR DC9 FLC ACKNOWLEDGED XING RESTR ON STAR OF 10000 FT. FLC EXECUTES CLB COMMAND FROM TCASII RA, OBSERVING ACR TFC BELOW. TCASII ACTIONS TAKEN DURING FREQ CHANGE TO APCH CTL.

Narrative: ACR X FLT FROM PIT TO DTW FEB/MON/98. CAPT FLYING AND BEING VECTORED BY ATC TO JOIN THE CETUS ARR A FEW MI NW OF THE DRYER VOR. CAPT HEARD INSTRUCTIONS BY ATC TO JOIN THE ARR AND DSND SO AS TO REACH THE CETUS INTXN BY 10000 FT. FO WAS HANDLING THE RADIOS BUT DID NOT HEAR THE CLRNC, SO THE CAPT REPEATED IT TO HIM AND THE FO ACKNOWLEDGED TO ATC THAT ACR X WOULD CROSS THE CETUS INTXN AT 10000 FT. AS THE CAPT EXECUTED THE DSCNT, HE COULD SEE POSSIBLE CONFLICTING ACR Y TFC ON THE TCASII APCHING 5-8 MI IN FRONT OF HIM, SO HE LEVELED OFF ABOVE THE TFC, NEVER REACHING 10000 FT. THE TCASII ISSUED A TA/RA ANYWAY, SO THE CAPT EXECUTED THE APPROPRIATE RESPONSE CLBING TO AND LEVELING AT 12000 FT. A FREQ CHANGE FROM ATC TO APCH CTL WAS ISSUED JUST AS THIS WAS HAPPENING. ALTHOUGH 12000 FT IS THE ALT NORMALLY ASSIGNED ACCORDING TO THE DEPICTION ON THE CETUS ARR, THERE WAS ABSOLUTELY NO QUESTION IN THE CAPT'S MIND THAT 10000 FT WAS THE ALT ASSIGNED AND ACKNOWLEDGED BACK TO THE ATC CTLR ISSUING THE CLRNC.

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.