Narrative:

While on an 8 mi final approach to runway 35L at denver international airport, the control tower operator radioed 'aircraft X make a right turn to heading 095 degrees and climb to 8000 ft.' I acknowledged the call by reading back the instructions and using our call sign, aircraft X. Upon completing the turn to 095 degrees, we could now see a B737 (Y) on approach to runway 35R. We continued the climb to 8000 ft and passed within 300 ft of the descending B737. I then radioed the control tower and requested further instructions. The tower operator stated that the turn and climb had been for another aircraft. The tower then handed us off to approach control and we were vectored back to an approach and landing on runway 35L. We immediately contacted the control tower and TRACON approach by telephone to discuss this incident. The tower chief had already listened to the audio tapes of the 2-WAY radio communications and had determined that the tower controller had erroneously called aircraft X when the instructions were for aircraft Z (C340). Had the instructions not been given with a tone of urgency, I would have queried the tower operator before acknowledging the instructions. The inflection of voice indicated to me a conflict of some kind that needed immediate attention without explanation. Reading back the instructions verbatim, as they were given to me, along with our call sign was a final opportunity for the tower controller to realize that the aircraft responding was not the aircraft that the controller actually intended to turn and climb.

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Original NASA ASRS Text

Title: DEN ATCT LCL CTLR CONFUSES CALL SIGNS OF AN LR35 AND C340, PUTTING THE WRONG ACFT INTO CONFLICT WITH A B737 ON FINAL APCH.

Narrative: WHILE ON AN 8 MI FINAL APCH TO RWY 35L AT DENVER INTL ARPT, THE CTL TWR OPERATOR RADIOED 'ACFT X MAKE A R TURN TO HDG 095 DEGS AND CLB TO 8000 FT.' I ACKNOWLEDGED THE CALL BY READING BACK THE INSTRUCTIONS AND USING OUR CALL SIGN, ACFT X. UPON COMPLETING THE TURN TO 095 DEGS, WE COULD NOW SEE A B737 (Y) ON APCH TO RWY 35R. WE CONTINUED THE CLB TO 8000 FT AND PASSED WITHIN 300 FT OF THE DSNDING B737. I THEN RADIOED THE CTL TWR AND REQUESTED FURTHER INSTRUCTIONS. THE TWR OPERATOR STATED THAT THE TURN AND CLB HAD BEEN FOR ANOTHER ACFT. THE TWR THEN HANDED US OFF TO APCH CTL AND WE WERE VECTORED BACK TO AN APCH AND LNDG ON RWY 35L. WE IMMEDIATELY CONTACTED THE CTL TWR AND TRACON APCH BY TELEPHONE TO DISCUSS THIS INCIDENT. THE TWR CHIEF HAD ALREADY LISTENED TO THE AUDIO TAPES OF THE 2-WAY RADIO COMS AND HAD DETERMINED THAT THE TWR CTLR HAD ERRONEOUSLY CALLED ACFT X WHEN THE INSTRUCTIONS WERE FOR ACFT Z (C340). HAD THE INSTRUCTIONS NOT BEEN GIVEN WITH A TONE OF URGENCY, I WOULD HAVE QUERIED THE TWR OPERATOR BEFORE ACKNOWLEDGING THE INSTRUCTIONS. THE INFLECTION OF VOICE INDICATED TO ME A CONFLICT OF SOME KIND THAT NEEDED IMMEDIATE ATTN WITHOUT EXPLANATION. READING BACK THE INSTRUCTIONS VERBATIM, AS THEY WERE GIVEN TO ME, ALONG WITH OUR CALL SIGN WAS A FINAL OPPORTUNITY FOR THE TWR CTLR TO REALIZE THAT THE ACFT RESPONDING WAS NOT THE ACFT THAT THE CTLR ACTUALLY INTENDED TO TURN AND CLB.

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.