Narrative:

Air carrier xyz called for taxi instructions. I taxied the aircraft to the runway. When I passed the strip to local control; I passed air carrier ayz. Air carrier ayz got released by TRACON. The local controller using the callsign air carrier ayz put air carrier xyz into position on the runway and then subsequently cleared air carrier xyz for takeoff using the callsign air carrier ayz. The pilot of air carrier xyz responded to air carrier ayz each time and began using that callsign as well. After the aircraft got airborne he tagged up as air carrier xyz and then we realized what had happened.

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Original NASA ASRS Text

Title: A Tower Controller reported they issued a departure clearance to the wrong aircraft due to similar sounding call signs from the same company.

Narrative: Air Carrier XYZ called for taxi instructions. I taxied the aircraft to the runway. When I passed the strip to Local Control; I passed Air Carrier AYZ. Air Carrier AYZ got released by TRACON. The Local Controller using the callsign Air Carrier AYZ put Air Carrier XYZ into position on the runway and then subsequently cleared Air Carrier XYZ for takeoff using the callsign Air Carrier AYZ. The Pilot of Air Carrier XYZ responded to Air Carrier AYZ each time and began using that callsign as well. After the aircraft got airborne he tagged up as Air Carrier XYZ and then we realized what had happened.

Data retrieved from NASA's ASRS site 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.