Narrative:

The flight plan called for routing from jot to dnv and the milan 1 arrival. The arrival from over dnv to shb is not direct and contains a southerly and then easterly routing. ZAU cleared our flight direct from a point approximately 30 mi southeast of jot direct to shb thus avoiding most of the arrival. The flight was proceeding as cleared when the center issued a 20 degree heading to the south to avoid a military training area. Shortly after this a change in altitude was given as well as a clearance to proceed once again to shb. As we initiated a slow descent, to what we believed was the cleared altitude, the center issued a frequency change. Prior to initiating contact on the new center frequency, our TCASII alerted with a TA. As our attention was called to the 'alert' the TCASII went into an RA. As we analyzed and began to react to the RA, the center called asking our altitude and immediately issued a right turn to increase spacing with the TCASII traffic. The center asked our altitude and it was at this point we were informed we went through the altitude issued by the last center. The center says that we were cleared to FL270, the crew believes we were cleared to FL240. The altitude of FL240 was in our altitude alert box. The procedure is for the PNF to set the altitude issued in the box and point to it till the other pilot confirms the altitude. We had done this procedure the previous 2 days as we always do, so we believe that we properly set the altitude and followed the procedure.

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Original NASA ASRS Text

Title: FLT OVERSHOT ASSIGNED ALT IN DSCNT, DSNDED THROUGH AN OCCUPIED ALT AND GOT A TCASII RA.

Narrative: THE FLT PLAN CALLED FOR ROUTING FROM JOT TO DNV AND THE MILAN 1 ARR. THE ARR FROM OVER DNV TO SHB IS NOT DIRECT AND CONTAINS A SOUTHERLY AND THEN EASTERLY ROUTING. ZAU CLRED OUR FLT DIRECT FROM A POINT APPROX 30 MI SE OF JOT DIRECT TO SHB THUS AVOIDING MOST OF THE ARR. THE FLT WAS PROCEEDING AS CLRED WHEN THE CTR ISSUED A 20 DEG HDG TO THE S TO AVOID A MIL TRAINING AREA. SHORTLY AFTER THIS A CHANGE IN ALT WAS GIVEN AS WELL AS A CLRNC TO PROCEED ONCE AGAIN TO SHB. AS WE INITIATED A SLOW DSCNT, TO WHAT WE BELIEVED WAS THE CLRED ALT, THE CTR ISSUED A FREQ CHANGE. PRIOR TO INITIATING CONTACT ON THE NEW CTR FREQ, OUR TCASII ALERTED WITH A TA. AS OUR ATTN WAS CALLED TO THE 'ALERT' THE TCASII WENT INTO AN RA. AS WE ANALYZED AND BEGAN TO REACT TO THE RA, THE CTR CALLED ASKING OUR ALT AND IMMEDIATELY ISSUED A R TURN TO INCREASE SPACING WITH THE TCASII TFC. THE CTR ASKED OUR ALT AND IT WAS AT THIS POINT WE WERE INFORMED WE WENT THROUGH THE ALT ISSUED BY THE LAST CTR. THE CTR SAYS THAT WE WERE CLRED TO FL270, THE CREW BELIEVES WE WERE CLRED TO FL240. THE ALT OF FL240 WAS IN OUR ALT ALERT BOX. THE PROC IS FOR THE PNF TO SET THE ALT ISSUED IN THE BOX AND POINT TO IT TILL THE OTHER PLT CONFIRMS THE ALT. WE HAD DONE THIS PROC THE PREVIOUS 2 DAYS AS WE ALWAYS DO, SO WE BELIEVE THAT WE PROPERLY SET THE ALT AND FOLLOWED THE PROC.

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.