Narrative:

During ground operations, I expected and planned for a takeoff on runway 8. Our taxi clearance from ramp was to taxi west from gate to 3W. This meant a very short taxi to a takeoff on either runways 34R, 34L, or 25. I chose runway 34R and did all the performance and loaded the FMGC again. We then spoke to ground and were told to expect runway 34L. Again, I sent for the performance and loaded the FMGC. I then informed the captain I was heads down, needed more time, and was behind. To the captain's credit, he assured me to take all the time I needed and not to rush. During this time, tower cleared us for takeoff on runway 34L, at which point the captain informed them we needed more time. They cancelled our takeoff clearance and told us to finish our checks on D2. I finished all the checks and informed the captain. Then I thought I heard our takeoff clearance for runway 34L. The captain actually read back the takeoff clearance to tower, taxied the aircraft onto the runway, said 'your throttles' during the turn and then transmitted to tower, 'confirm air carrier X is cleared for takeoff?' tower then started to speak with another aircraft. I then said, 'I heard the clearance' and he said 'ok' and I continued the takeoff. After liftoff, tower asked where we were, and informed us that they cleared air carrier Y for takeoff. No conflict was evident to us and no avoidance vectors were issued that I heard. Human factors: this was the 4TH leg of the day and third aircraft change. I finished A320 transition in march and IOE in april. I had never flown 4 legs in 1 day in my career. Without a doubt I was tired, but I felt I was fit to fly. Looking back on it, I should have stopped the takeoff roll (very low speed) and let the captain sort out the clearance with tower. I also feel tower should have paid attention to the captain's readback, especially since it was not busy. Supplemental information from acn 616612: as we rolled into position, I queried tower to confirm we were cleared for takeoff as I thought it odd that he somehow knew we were ready. I also queried because as we started takeoff I noticed an rj pulling up to hold short. The copilot then confirmed he heard the takeoff clearance for us. Just before rotation tower said 'where are you?' at 1000 ft, I told tower we were airborne. Controller started ranting about how he never gave us clearance for takeoff. I should have prevailed with my query and got the confirmation from tower. I was easily swayed by the copilot confirming the clearance.

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Original NASA ASRS Text

Title: A320 TAKES OFF FROM DEN AFTER ACCEPTING CLRNC FOR ANOTHER ACFT.

Narrative: DURING GND OPS, I EXPECTED AND PLANNED FOR A TKOF ON RWY 8. OUR TAXI CLRNC FROM RAMP WAS TO TAXI W FROM GATE TO 3W. THIS MEANT A VERY SHORT TAXI TO A TKOF ON EITHER RWYS 34R, 34L, OR 25. I CHOSE RWY 34R AND DID ALL THE PERFORMANCE AND LOADED THE FMGC AGAIN. WE THEN SPOKE TO GND AND WERE TOLD TO EXPECT RWY 34L. AGAIN, I SENT FOR THE PERFORMANCE AND LOADED THE FMGC. I THEN INFORMED THE CAPT I WAS HEADS DOWN, NEEDED MORE TIME, AND WAS BEHIND. TO THE CAPT'S CREDIT, HE ASSURED ME TO TAKE ALL THE TIME I NEEDED AND NOT TO RUSH. DURING THIS TIME, TWR CLRED US FOR TKOF ON RWY 34L, AT WHICH POINT THE CAPT INFORMED THEM WE NEEDED MORE TIME. THEY CANCELLED OUR TKOF CLRNC AND TOLD US TO FINISH OUR CHKS ON D2. I FINISHED ALL THE CHKS AND INFORMED THE CAPT. THEN I THOUGHT I HEARD OUR TKOF CLRNC FOR RWY 34L. THE CAPT ACTUALLY READ BACK THE TKOF CLRNC TO TWR, TAXIED THE ACFT ONTO THE RWY, SAID 'YOUR THROTTLES' DURING THE TURN AND THEN XMITTED TO TWR, 'CONFIRM ACR X IS CLRED FOR TKOF?' TWR THEN STARTED TO SPEAK WITH ANOTHER ACFT. I THEN SAID, 'I HEARD THE CLRNC' AND HE SAID 'OK' AND I CONTINUED THE TKOF. AFTER LIFTOFF, TWR ASKED WHERE WE WERE, AND INFORMED US THAT THEY CLRED ACR Y FOR TKOF. NO CONFLICT WAS EVIDENT TO US AND NO AVOIDANCE VECTORS WERE ISSUED THAT I HEARD. HUMAN FACTORS: THIS WAS THE 4TH LEG OF THE DAY AND THIRD ACFT CHANGE. I FINISHED A320 TRANSITION IN MARCH AND IOE IN APRIL. I HAD NEVER FLOWN 4 LEGS IN 1 DAY IN MY CAREER. WITHOUT A DOUBT I WAS TIRED, BUT I FELT I WAS FIT TO FLY. LOOKING BACK ON IT, I SHOULD HAVE STOPPED THE TKOF ROLL (VERY LOW SPD) AND LET THE CAPT SORT OUT THE CLRNC WITH TWR. I ALSO FEEL TWR SHOULD HAVE PAID ATTN TO THE CAPT'S READBACK, ESPECIALLY SINCE IT WAS NOT BUSY. SUPPLEMENTAL INFO FROM ACN 616612: AS WE ROLLED INTO POS, I QUERIED TWR TO CONFIRM WE WERE CLRED FOR TKOF AS I THOUGHT IT ODD THAT HE SOMEHOW KNEW WE WERE READY. I ALSO QUERIED BECAUSE AS WE STARTED TKOF I NOTICED AN RJ PULLING UP TO HOLD SHORT. THE COPLT THEN CONFIRMED HE HEARD THE TKOF CLRNC FOR US. JUST BEFORE ROTATION TWR SAID 'WHERE ARE YOU?' AT 1000 FT, I TOLD TWR WE WERE AIRBORNE. CTLR STARTED RANTING ABOUT HOW HE NEVER GAVE US CLRNC FOR TKOF. I SHOULD HAVE PREVAILED WITH MY QUERY AND GOT THE CONFIRMATION FROM TWR. I WAS EASILY SWAYED BY THE COPLT CONFIRMING THE CLRNC.

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.