Narrative:

While operating air carrier flight #aabc on the eau claire arrival (eau.EAU6) into msp, we received a clearance to descend to FL240 from ZAU. The clearance was acknowledged and read back. At approximately FL302, ZAU asked if we were descending. We immediately leveled off and answered in the affirmative, as per our clearance. The controller then asked if air carrier flight #abc was descending. The other air carrier answered negative. The controller then gave air carrier abc clearance to FL240 and we were to stay at FL310. We returned to FL310. The factors that may have contributed to this incident, as we saw it, could have been the practice of operating on more than 1 frequency by the controller. Our frequency had very little traffic (121.37), but if the controller was working other aircraft on other frequencys, that would have contributed to the confusion. Another practice often used, not in this case, is to make aircraft with similar call signs aware of each other. In my opinion, that would cause us to be extra vigilant. Finally, the readback. We were very deliberate with our readback of the clearance preceded with our call sign. Absent any correction, that leaves a perception the proper aircraft got the proper clearance. At no time was there any danger because the controller became aware of the situation early enough to prevent any conflict.

Related reports:

Google
 

Original NASA ASRS Text

Title: MD88 FLT CREW ACKNOWLEDGED DSND CLRNC MEANT FOR ANOTHER SIMILAR SOUNDING ACR, BUT UNCHALLENGED BY ZAU.

Narrative: WHILE OPERATING ACR FLT #AABC ON THE EAU CLAIRE ARR (EAU.EAU6) INTO MSP, WE RECEIVED A CLRNC TO DSND TO FL240 FROM ZAU. THE CLRNC WAS ACKNOWLEDGED AND READ BACK. AT APPROX FL302, ZAU ASKED IF WE WERE DSNDING. WE IMMEDIATELY LEVELED OFF AND ANSWERED IN THE AFFIRMATIVE, AS PER OUR CLRNC. THE CTLR THEN ASKED IF ACR FLT #ABC WAS DSNDING. THE OTHER ACR ANSWERED NEGATIVE. THE CTLR THEN GAVE ACR ABC CLRNC TO FL240 AND WE WERE TO STAY AT FL310. WE RETURNED TO FL310. THE FACTORS THAT MAY HAVE CONTRIBUTED TO THIS INCIDENT, AS WE SAW IT, COULD HAVE BEEN THE PRACTICE OF OPERATING ON MORE THAN 1 FREQ BY THE CTLR. OUR FREQ HAD VERY LITTLE TFC (121.37), BUT IF THE CTLR WAS WORKING OTHER ACFT ON OTHER FREQS, THAT WOULD HAVE CONTRIBUTED TO THE CONFUSION. ANOTHER PRACTICE OFTEN USED, NOT IN THIS CASE, IS TO MAKE ACFT WITH SIMILAR CALL SIGNS AWARE OF EACH OTHER. IN MY OPINION, THAT WOULD CAUSE US TO BE EXTRA VIGILANT. FINALLY, THE READBACK. WE WERE VERY DELIBERATE WITH OUR READBACK OF THE CLRNC PRECEDED WITH OUR CALL SIGN. ABSENT ANY CORRECTION, THAT LEAVES A PERCEPTION THE PROPER ACFT GOT THE PROPER CLRNC. AT NO TIME WAS THERE ANY DANGER BECAUSE THE CTLR BECAME AWARE OF THE SIT EARLY ENOUGH TO PREVENT ANY CONFLICT.

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.