Narrative:

Given descent clearance to FL180 by ARTCC. Acknowledged clearance and read back FL180. Descending through FL193, ATC asked if we were level at FL200. We indicated our descent clearance to FL180 and he immediately told us to climb back to FL200. The controller was overworked with a runway change into sjc (runway 12 to runway 30) and the resultant STAR changes (jawws to elnido). When the event occurred, he told air carrier X (us) to turn right 40 degrees as well. He also told air carrier X to descend immediately, he really meant to give the clearance to air carrier Y involved. Obviously the controller was confused and overworked, and the ATC tapes will prove us right. It really doesn't matter who was right, just that there was a simple miscom that could have produced a dangerous situation. We don't know if there was a loss of separation, but we do know that we didn't get any TCASII alerts. I really wonder what the ultimate outcome of the FAA's new 'policy' concerning readbacks and the lack of protection they provide now. Why even bother reading anything back? I also wonder what happens when the controller is at fault. The perception of these points leads professional aviators to believe that we are always suspect and not trusted.

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Original NASA ASRS Text

Title: ACR READ BACK ALT ASSIGNMENT THAT WAS GIVEN BUT NOT INTENDED. CTLR DID NOT CATCH THE ERROR AND DISCOVERED IT ONLY WHEN THE ACFT DSNDED BELOW ALT THAT HE EXPECTED.

Narrative: GIVEN DSCNT CLRNC TO FL180 BY ARTCC. ACKNOWLEDGED CLRNC AND READ BACK FL180. DSNDING THROUGH FL193, ATC ASKED IF WE WERE LEVEL AT FL200. WE INDICATED OUR DSCNT CLRNC TO FL180 AND HE IMMEDIATELY TOLD US TO CLB BACK TO FL200. THE CTLR WAS OVERWORKED WITH A RWY CHANGE INTO SJC (RWY 12 TO RWY 30) AND THE RESULTANT STAR CHANGES (JAWWS TO ELNIDO). WHEN THE EVENT OCCURRED, HE TOLD ACR X (US) TO TURN R 40 DEGS AS WELL. HE ALSO TOLD ACR X TO DSND IMMEDIATELY, HE REALLY MEANT TO GIVE THE CLRNC TO ACR Y INVOLVED. OBVIOUSLY THE CTLR WAS CONFUSED AND OVERWORKED, AND THE ATC TAPES WILL PROVE US RIGHT. IT REALLY DOESN'T MATTER WHO WAS RIGHT, JUST THAT THERE WAS A SIMPLE MISCOM THAT COULD HAVE PRODUCED A DANGEROUS SIT. WE DON'T KNOW IF THERE WAS A LOSS OF SEPARATION, BUT WE DO KNOW THAT WE DIDN'T GET ANY TCASII ALERTS. I REALLY WONDER WHAT THE ULTIMATE OUTCOME OF THE FAA'S NEW 'POLICY' CONCERNING READBACKS AND THE LACK OF PROTECTION THEY PROVIDE NOW. WHY EVEN BOTHER READING ANYTHING BACK? I ALSO WONDER WHAT HAPPENS WHEN THE CTLR IS AT FAULT. THE PERCEPTION OF THESE POINTS LEADS PROFESSIONAL AVIATORS TO BELIEVE THAT WE ARE ALWAYS SUSPECT AND NOT TRUSTED.

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.