Narrative:

We were taxiing out for an intersection takeoff at runway 7L at intersection A8 in las. There were a few aircraft holding short waiting to take off and as we approached intersection A6; the tower asked if we could accept a takeoff from that intersection. I remembered a stopping margin of over 4500 ft with a reduced power takeoff from intersection A8. After looking at the airport diagram; I estimated the runway available would be about 9000 ft from intersection A6. In my mind I justified accepting the clearance because of the large reduction takeoff from intersection A8; lack of terrain east of the field; the good field conditions; and my estimated 9000 ft of runway available from intersection A6. As I told the first officer to accept the clearance; he asked if we had the numbers. I incorrectly assumed that since we take off many places with less runway available and there is no terrain; the computer would have the data. I committed a CRM blunder and disregarded his concern about data and took off without updating takeoff data from the new intersection. Had I stopped the aircraft and checked the data per the fom; I would have realized the company does not allow a takeoff from that intersection. As my mind raced on departure; I realized my mistake. My first officer did ask the right questions and I totally screwed up by not adequately acknowledging his concerns. This is probably what I'm beating myself up most about. I disregarded the backup who is there to monitor me and be the safety net. I am aware of the requirement to have data for each takeoff and should have stopped the aircraft; told ATC we needed to run numbers without the first officer asking the question. I had another chance to do the right thing after the first officer raised his concern. It would have taken 1 min. Supplemental information from acn 785595: in retrospect; the captain and I agreed that it was a dumb mistake that was easily avoided. The captain 'assumed' that we had data from that intersection and I thought the captain 'knew.'

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Original NASA ASRS Text

Title: B737 FLT CREW DEPARTS RWY 7L AT A6 IN LAS WITHOUT ASSOCIATED DATA.

Narrative: WE WERE TAXIING OUT FOR AN INTXN TKOF AT RWY 7L AT INTXN A8 IN LAS. THERE WERE A FEW ACFT HOLDING SHORT WAITING TO TAKE OFF AND AS WE APCHED INTXN A6; THE TWR ASKED IF WE COULD ACCEPT A TKOF FROM THAT INTXN. I REMEMBERED A STOPPING MARGIN OF OVER 4500 FT WITH A REDUCED PWR TKOF FROM INTXN A8. AFTER LOOKING AT THE ARPT DIAGRAM; I ESTIMATED THE RWY AVAILABLE WOULD BE ABOUT 9000 FT FROM INTXN A6. IN MY MIND I JUSTIFIED ACCEPTING THE CLRNC BECAUSE OF THE LARGE REDUCTION TKOF FROM INTXN A8; LACK OF TERRAIN E OF THE FIELD; THE GOOD FIELD CONDITIONS; AND MY ESTIMATED 9000 FT OF RWY AVAILABLE FROM INTXN A6. AS I TOLD THE FO TO ACCEPT THE CLRNC; HE ASKED IF WE HAD THE NUMBERS. I INCORRECTLY ASSUMED THAT SINCE WE TAKE OFF MANY PLACES WITH LESS RWY AVAILABLE AND THERE IS NO TERRAIN; THE COMPUTER WOULD HAVE THE DATA. I COMMITTED A CRM BLUNDER AND DISREGARDED HIS CONCERN ABOUT DATA AND TOOK OFF WITHOUT UPDATING TKOF DATA FROM THE NEW INTXN. HAD I STOPPED THE ACFT AND CHKED THE DATA PER THE FOM; I WOULD HAVE REALIZED THE COMPANY DOES NOT ALLOW A TKOF FROM THAT INTXN. AS MY MIND RACED ON DEP; I REALIZED MY MISTAKE. MY FO DID ASK THE RIGHT QUESTIONS AND I TOTALLY SCREWED UP BY NOT ADEQUATELY ACKNOWLEDGING HIS CONCERNS. THIS IS PROBABLY WHAT I'M BEATING MYSELF UP MOST ABOUT. I DISREGARDED THE BACKUP WHO IS THERE TO MONITOR ME AND BE THE SAFETY NET. I AM AWARE OF THE REQUIREMENT TO HAVE DATA FOR EACH TKOF AND SHOULD HAVE STOPPED THE ACFT; TOLD ATC WE NEEDED TO RUN NUMBERS WITHOUT THE FO ASKING THE QUESTION. I HAD ANOTHER CHANCE TO DO THE RIGHT THING AFTER THE FO RAISED HIS CONCERN. IT WOULD HAVE TAKEN 1 MIN. SUPPLEMENTAL INFO FROM ACN 785595: IN RETROSPECT; THE CAPT AND I AGREED THAT IT WAS A DUMB MISTAKE THAT WAS EASILY AVOIDED. THE CAPT 'ASSUMED' THAT WE HAD DATA FROM THAT INTXN AND I THOUGHT THE CAPT 'KNEW.'

Data retrieved from NASA's ASRS site as of May 2009 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.