Narrative:

We were given position and hold on runway 25R at lax. Our call sign was company bxd. While in position we were told to 'company bxd at the shoreline turn left 220, climb and maintain 5000', contact departure control.' this is the standard information given when cleared for takeoff from runway 25L or right at lax. However, I've since learned the controller intended those instructions for a previously departed aircraft but used our call sign. We were more or less primed to hear just what we heard, but assumed we were cleared for takeoff, but were not, after starting our roll I noticed an aircraft crossing the end of our runway (25R) and advised the captain to reject because of the incursion. Our reject occurred at approximately 70 KIAS with no real conflict with the other aircraft at the end of the runway. The primary misconception on our part was our expecting to hear exactly what the first 2/3 of the transmission contained, given standard operating communication at lax for a departure from runways 25L&right. After hearing the first part of the transmission we are always used to hearing the last part 'cleared for takeoff'. It's hard to admit complacency, but I feel we all took for granted our takeoff clearance after hearing exactly what we expected to hear initially.

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Original NASA ASRS Text

Title: WDB FLT CREW HEARD INSTRUCTIONS GIVEN WITH THEIR CALL SIGN. PERCEIVED AS TKOF CLRNC. ABORTED AS ACR CROSSED RWY AHEAD.

Narrative: WE WERE GIVEN POSITION AND HOLD ON RWY 25R AT LAX. OUR CALL SIGN WAS COMPANY BXD. WHILE IN POSITION WE WERE TOLD TO 'COMPANY BXD AT THE SHORELINE TURN LEFT 220, CLIMB AND MAINTAIN 5000', CONTACT DEP CTL.' THIS IS THE STANDARD INFO GIVEN WHEN CLRED FOR TKOF FROM RWY 25L OR R AT LAX. HOWEVER, I'VE SINCE LEARNED THE CTLR INTENDED THOSE INSTRUCTIONS FOR A PREVIOUSLY DEPARTED ACFT BUT USED OUR CALL SIGN. WE WERE MORE OR LESS PRIMED TO HEAR JUST WHAT WE HEARD, BUT ASSUMED WE WERE CLRED FOR TKOF, BUT WERE NOT, AFTER STARTING OUR ROLL I NOTICED AN ACFT XING THE END OF OUR RWY (25R) AND ADVISED THE CAPT TO REJECT BECAUSE OF THE INCURSION. OUR REJECT OCCURRED AT APPROX 70 KIAS WITH NO REAL CONFLICT WITH THE OTHER ACFT AT THE END OF THE RWY. THE PRIMARY MISCONCEPTION ON OUR PART WAS OUR EXPECTING TO HEAR EXACTLY WHAT THE FIRST 2/3 OF THE XMISSION CONTAINED, GIVEN STANDARD OPERATING COM AT LAX FOR A DEP FROM RWYS 25L&R. AFTER HEARING THE FIRST PART OF THE XMISSION WE ARE ALWAYS USED TO HEARING THE LAST PART 'CLRED FOR TKOF'. IT'S HARD TO ADMIT COMPLACENCY, BUT I FEEL WE ALL TOOK FOR GRANTED OUR TKOF CLRNC AFTER HEARING EXACTLY WHAT WE EXPECTED TO HEAR INITIALLY.

Data retrieved from NASA's ASRS site as of August 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.