Narrative:

We received taxi clearance to 25R via taxiway J. I stopped our aircraft at the hold sign at cross taxiway 9 and made the statement to the crew that we needed the full length of 25R for takeoff. When lax tower cleared us into position on 25R at taxiway 8, the first officer advised him of our need for the full length. The tower then said that there were 2 other aircraft (both widebody transport's on taxiway J ahead of us and between taxiway 8 and the end of the runway) awaiting their #south prior to takeoff. Shortly thereafter, the tower cleared us for the full length of 25R. The first officer replied, 'understand you want us to back taxi for the full length of 25R.' tower responded with a 'roger.' as we started to turn onto taxiway 8, I asked the second officer to see if our gross weight would allow us to use 25L for takeoff. The second officer checked and responded that we could. The first officer advised the tower of that fact, but no reply was received. At that time we were turning onto 25R, and I back-taxied to the end of the runway. Lax tower then called us and said, 'that isn't quite what I wanted you to do.' I them made a 180 degree turn at the end and the first officer aid to the tower, 'I specifically asked if we were to back-taxi.' the tower responded with, 'you were cleared for the full length of 25R.' I then asked the first officer to check with the tower to see if we were to clear the runway. The tower told us to taxi up to taxiway 8 and clear there. Contributing factors were: the 2 widebody transport aircraft ahead of us on taxiway J that were taking a delay and prevented us from moving forward on that taxiway, the miscom concerning being cleared to back-taxi on the runway, the lack of an advisement that we were to stay in takeoff sequence behind the other 2 widebody transport's, and not having our 'cleared into position and hold' clearance cancelled.

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Original NASA ASRS Text

Title: ACR WDB RWY TRANSGRESSION AT LAX.

Narrative: WE RECEIVED TAXI CLRNC TO 25R VIA TXWY J. I STOPPED OUR ACFT AT THE HOLD SIGN AT CROSS TXWY 9 AND MADE THE STATEMENT TO THE CREW THAT WE NEEDED THE FULL LENGTH OF 25R FOR TKOF. WHEN LAX TWR CLRED US INTO POS ON 25R AT TXWY 8, THE F/O ADVISED HIM OF OUR NEED FOR THE FULL LENGTH. THE TWR THEN SAID THAT THERE WERE 2 OTHER ACFT (BOTH WDB'S ON TXWY J AHEAD OF US AND BTWN TXWY 8 AND THE END OF THE RWY) AWAITING THEIR #S PRIOR TO TKOF. SHORTLY THEREAFTER, THE TWR CLRED US FOR THE FULL LENGTH OF 25R. THE F/O REPLIED, 'UNDERSTAND YOU WANT US TO BACK TAXI FOR THE FULL LENGTH OF 25R.' TWR RESPONDED WITH A 'ROGER.' AS WE STARTED TO TURN ONTO TXWY 8, I ASKED THE S/O TO SEE IF OUR GROSS WT WOULD ALLOW US TO USE 25L FOR TKOF. THE S/O CHKED AND RESPONDED THAT WE COULD. THE F/O ADVISED THE TWR OF THAT FACT, BUT NO REPLY WAS RECEIVED. AT THAT TIME WE WERE TURNING ONTO 25R, AND I BACK-TAXIED TO THE END OF THE RWY. LAX TWR THEN CALLED US AND SAID, 'THAT ISN'T QUITE WHAT I WANTED YOU TO DO.' I THEM MADE A 180 DEG TURN AT THE END AND THE F/O AID TO THE TWR, 'I SPECIFICALLY ASKED IF WE WERE TO BACK-TAXI.' THE TWR RESPONDED WITH, 'YOU WERE CLRED FOR THE FULL LENGTH OF 25R.' I THEN ASKED THE F/O TO CHK WITH THE TWR TO SEE IF WE WERE TO CLR THE RWY. THE TWR TOLD US TO TAXI UP TO TXWY 8 AND CLR THERE. CONTRIBUTING FACTORS WERE: THE 2 WDB ACFT AHEAD OF US ON TXWY J THAT WERE TAKING A DELAY AND PREVENTED US FROM MOVING FORWARD ON THAT TXWY, THE MISCOM CONCERNING BEING CLRED TO BACK-TAXI ON THE RWY, THE LACK OF AN ADVISEMENT THAT WE WERE TO STAY IN TKOF SEQUENCE BEHIND THE OTHER 2 WDB'S, AND NOT HAVING OUR 'CLRED INTO POS AND HOLD' CLRNC CANCELLED.

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.