Narrative:

Departed grand rapids, handed over to ZAU cleared direct to fwa VORTAC to climb to and maintain FL190. Reaching FL190 we heard the controller clear someone to FL230 but we did not hear a call sign. A few moments later, we were instructed to turn right 20 degrees for our climb. My first officer acknowledged this stating 'turning right to 210 degrees climbing to FL230 call sign.' at FL203, the controller stated 'call sign I did not clear you to climb out of FL190.' I immediately terminated the climb and began to descend back to FL190. Moments later, the same controller cleared us to climb to FL230. A follow up phone call to the controller and the supervisor cleared up some of this mystery. The controller said the sector was in the process of being split when we checked in. The controller was simulcasting on 2 different frequencys. The clearance to climb was to another aircraft that was in another sector beyond the 40 mi range of our TCASII supplemental information from acn 306072: after check- in, we heard a call to climb and maintain FL230 but we were unsure of the call sign. When we didn't hear anyone else response -- we responded by saying 'cleared to FL230, call sign.' there was no immediate response but moments later we received a call from center stating, 'call sign turn right 20 degrees for your climb.' we were under the impression that we were the only aircraft he was in contact with.

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Original NASA ASRS Text

Title: ACR FLC ALTDEV RESULTED FROM MISCOM BTWN FLC AND ATC.

Narrative: DEPARTED GRAND RAPIDS, HANDED OVER TO ZAU CLRED DIRECT TO FWA VORTAC TO CLB TO AND MAINTAIN FL190. REACHING FL190 WE HEARD THE CTLR CLR SOMEONE TO FL230 BUT WE DID NOT HEAR A CALL SIGN. A FEW MOMENTS LATER, WE WERE INSTRUCTED TO TURN R 20 DEGS FOR OUR CLB. MY FO ACKNOWLEDGED THIS STATING 'TURNING R TO 210 DEGS CLBING TO FL230 CALL SIGN.' AT FL203, THE CTLR STATED 'CALL SIGN I DID NOT CLR YOU TO CLB OUT OF FL190.' I IMMEDIATELY TERMINATED THE CLB AND BEGAN TO DSND BACK TO FL190. MOMENTS LATER, THE SAME CTLR CLRED US TO CLB TO FL230. A FOLLOW UP PHONE CALL TO THE CTLR AND THE SUPVR CLRED UP SOME OF THIS MYSTERY. THE CTLR SAID THE SECTOR WAS IN THE PROCESS OF BEING SPLIT WHEN WE CHKED IN. THE CTLR WAS SIMULCASTING ON 2 DIFFERENT FREQS. THE CLRNC TO CLB WAS TO ANOTHER ACFT THAT WAS IN ANOTHER SECTOR BEYOND THE 40 MI RANGE OF OUR TCASII SUPPLEMENTAL INFO FROM ACN 306072: AFTER CHK- IN, WE HEARD A CALL TO CLB AND MAINTAIN FL230 BUT WE WERE UNSURE OF THE CALL SIGN. WHEN WE DIDN'T HEAR ANYONE ELSE RESPONSE -- WE RESPONDED BY SAYING 'CLRED TO FL230, CALL SIGN.' THERE WAS NO IMMEDIATE RESPONSE BUT MOMENTS LATER WE RECEIVED A CALL FROM CTR STATING, 'CALL SIGN TURN R 20 DEGS FOR YOUR CLB.' WE WERE UNDER THE IMPRESSION THAT WE WERE THE ONLY ACFT HE WAS IN CONTACT WITH.

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.