Narrative:

During approach into mco the controller issued us a clearance for a 185 degree heading and descent to 5000 ft. At approximately 8400 ft we got TA then an RA to climb which first officer (PF) initiated. Controller then stated we were supposed to be at 9000 ft. I responded 'no sir; you cleared us to 5000 ft.' he had previously made many call sign mistakes while we were in his airspace. He had been calling us air carrier Y. He made that mistake numerous times. He even apologized to air carrier Y once for calling him by our call sign air carrier X. I talked to the tower chief after the incident and he admitted that yes; his controller had made numerous call sign mistakes. After reviewing the tapes; he told us that my response of the full clearance was not on the tape; and that his controller had cleared air carrier Y to 5000 ft but had called him air carrier X. I am sure that I responded with the full clearance but can only assume it was blocked by air carrier Y. I was aware that the controller was making these mistakes and probably should have been more vigilant in listening and then responding.

Google
 

Original NASA ASRS Text

Title: A319 FLT CREW REPORTS CALL SIGN MIX-UP WITH MCO APPROACH THAT RESULTS IN DESCENT BELOW CLEARED ALTITUDE AND A TCAS RA WHICH THE FLT CREW RESPONDED TO.

Narrative: DURING APCH INTO MCO THE CTLR ISSUED US A CLRNC FOR A 185 DEG HDG AND DSCNT TO 5000 FT. AT APPROX 8400 FT WE GOT TA THEN AN RA TO CLB WHICH FO (PF) INITIATED. CTLR THEN STATED WE WERE SUPPOSED TO BE AT 9000 FT. I RESPONDED 'NO SIR; YOU CLRED US TO 5000 FT.' HE HAD PREVIOUSLY MADE MANY CALL SIGN MISTAKES WHILE WE WERE IN HIS AIRSPACE. HE HAD BEEN CALLING US ACR Y. HE MADE THAT MISTAKE NUMEROUS TIMES. HE EVEN APOLOGIZED TO ACR Y ONCE FOR CALLING HIM BY OUR CALL SIGN ACR X. I TALKED TO THE TWR CHIEF AFTER THE INCIDENT AND HE ADMITTED THAT YES; HIS CTLR HAD MADE NUMEROUS CALL SIGN MISTAKES. AFTER REVIEWING THE TAPES; HE TOLD US THAT MY RESPONSE OF THE FULL CLRNC WAS NOT ON THE TAPE; AND THAT HIS CTLR HAD CLRED ACR Y TO 5000 FT BUT HAD CALLED HIM ACR X. I AM SURE THAT I RESPONDED WITH THE FULL CLRNC BUT CAN ONLY ASSUME IT WAS BLOCKED BY ACR Y. I WAS AWARE THAT THE CTLR WAS MAKING THESE MISTAKES AND PROBABLY SHOULD HAVE BEEN MORE VIGILANT IN LISTENING AND THEN RESPONDING.

Data retrieved from NASA's ASRS site as of January 2009 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.