Narrative:

3 aircraft (mixed types) taxied at same time - air carrier X, xx, XXX, on taxi the clearance sounded 'clipped' but first officer acknowledged with full proper call sign - air carrier xx - and recalled to confirm that we had indeed been cleared - ground answered 'affirmative.' we taxied to hold short point and were #1 for takeoff. When tower again sounded 'clipped.' since we were #1 we taxied into position to hold. Tower cleared 'air carrier X for takeoff we challenged them by starting we were' air carrier xx in position.' tower said 'hold position' then in 5-6 seconds cleared us. Air carrier xx for takeoff (air carrier X was #2 - air carrier XXX was #3) we departed when switched to departure tower added 'thanks for the help.' I don't know whether he mixed strips but I know we thought heard our call sign - both for taxi and takeoff. I will report 'clipped' xmissions in future and continue to confirm callsigns if any confusion exists. Supplemental information from acn 203354: during pushback/taxi at extremely busy period we were given pushback clearance from gate. After tug and ground vehicles were clear we called for taxi. Our flight number was air carrier xx. After transmission asking for taxi clearance we heard what sounded like a clearance for air carrier xx to taxi to 29R. The first part was blocked so we acknowledged with the full call sign 'air carrier xx.' ATC did not respond any further.

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Original NASA ASRS Text

Title: SIMILAR SOUNDING A/N LEADS TO CONFUSION AT THE RWY ENTRY AREA. ANSWER TO WRONG CALL SIGN.

Narrative: 3 ACFT (MIXED TYPES) TAXIED AT SAME TIME - ACR X, XX, XXX, ON TAXI THE CLRNC SOUNDED 'CLIPPED' BUT FO ACKNOWLEDGED WITH FULL PROPER CALL SIGN - ACR XX - AND RECALLED TO CONFIRM THAT WE HAD INDEED BEEN CLRED - GND ANSWERED 'AFFIRMATIVE.' WE TAXIED TO HOLD SHORT POINT AND WERE #1 FOR TKOF. WHEN TWR AGAIN SOUNDED 'CLIPPED.' SINCE WE WERE #1 WE TAXIED INTO POS TO HOLD. TWR CLRED 'ACR X FOR TKOF WE CHALLENGED THEM BY STARTING WE WERE' ACR XX IN POS.' TWR SAID 'HOLD POS' THEN IN 5-6 SECONDS CLRED US. ACR XX FOR TKOF (ACR X WAS #2 - ACR XXX WAS #3) WE DEPARTED WHEN SWITCHED TO DEP TWR ADDED 'THANKS FOR THE HELP.' I DON'T KNOW WHETHER HE MIXED STRIPS BUT I KNOW WE THOUGHT HEARD OUR CALL SIGN - BOTH FOR TAXI AND TKOF. I WILL REPORT 'CLIPPED' XMISSIONS IN FUTURE AND CONTINUE TO CONFIRM CALLSIGNS IF ANY CONFUSION EXISTS. SUPPLEMENTAL INFO FROM ACN 203354: DURING PUSHBACK/TAXI AT EXTREMELY BUSY PERIOD WE WERE GIVEN PUSHBACK CLRNC FROM GATE. AFTER TUG AND GND VEHICLES WERE CLR WE CALLED FOR TAXI. OUR FLT NUMBER WAS ACR XX. AFTER XMISSION ASKING FOR TAXI CLRNC WE HEARD WHAT SOUNDED LIKE A CLRNC FOR ACR XX TO TAXI TO 29R. THE FIRST PART WAS BLOCKED SO WE ACKNOWLEDGED WITH THE FULL CALL SIGN 'ACR XX.' ATC DID NOT RESPOND ANY FURTHER.

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.