ACR LGT TKOF AT ACFT GROSS WEIGHT IN EXCESS OF MAXIMUM FOR RWY USED BASED ON ACFT PERFORMANCE.

Narrative

THE TKOF DATA CARD FOR THE FLT HAD BEEN COMPUTED BY THE S/O FOR RWY 36L USING A FLAPS 5 SETTING. THE TEMP WAS 56 DEG AND HE STATED THAT THE CARD AND FIGURES WERE GOOD FOR THAT RWY. UPON RECEIVING OUR TAXI CLRNC; WE WERE ASSIGNED RWY 36R FOR DEP DUE TO WHAT APPEARED TO BE A BACKUP OF DEPS ON 36L. THE CAPT AND I REVIEWED THE CORRECT TAXI ROUTE TO THE ASSIGNED RWY AFTER WE HAD RECEIVED OUR TAXI INSTRUCTIONS. AS IS NORMAL PROCEDURE; WE DELAYED STARTING THE CENTER ENGINE UNTIL CLOSER TO THE RWY IN ORDER TO SAVE FUEL. THE S/O WAS BUSY TALKING TO THE RAMP PERSONNEL TO VERIFY OUR WEIGHTS FOR DEP WHEN THE TKOF FLAPS WERE EXTENDED BY ME. I EXTENDED THEM TO FLAPS 5 AS INDICATED ON THE CARD. IT DID NOT ENTER MY MIND AT THAT TIME THAT A FLAPS 5 TKOF AT OUR WEIGHT WAS BASED ON RWY 36L NOT 36R AS WE WERE ASSIGNED. THE CENTER ENGINE WAS THEN STARTED AFTER THE FLAPS WERE EXTENDED AS IS NORMAL PROCEDURE. AFTER AN APPROX 5 MINUTE DELAY; WE WERE CLRD FOR TKOF. THE CHKLIST WAS COMPLETED BUT NO ONE EVER QUESTIONED THE FLAP SETTING. WE JUST ASSUMED EVERYTHING WAS NORMAL. I MADE THE TKOF. WINDS WERE RPTED 270 AT 4 KTS. DURING THE LATER STAGES OF THE TKOF IT WAS OBVIOUS THAT WE WERE GOING TO USE UP THE ENTIRE LENGTH. THE ROTATION WAS MADE JUST PRIOR TO VR TO EXPEDITE OUR DEP FROM THE RWY. I WAS CONCERNED; AS THE RWY END WAS RAPIDLY APCHING. THE REMAINDER OF THE TKOF AND FLT WAS UNEVENTFUL. IN THE REVIEW OF THAT TKOF LATER BY THE CREW; IT WAS DISCOVERED THAT WE HAD TAKEN OFF APPROX 9000 LBS OVER GROSS WEIGHT FOR THAT PARTICULAR RWY AND FLAP SETTING. THE EVENT I FEEL WAS CAUSED BY COMPLACENCY DUE TO THE FACT THAT ALL CREWMEMBERS HAD A GOOD RAPPORT AND BECAUSE OF THIS WE DIDN'T QUESTION EACH OTHERS' ACTIONS ENOUGH. A CONTRIBUTING FACTOR MAY HAVE BEEN THE LATE WEIGHT INFORMATION RELAYED TO THE ENGINEER BY THE RAMP PERSONNEL WHICH CAUSED A BREAK IN THE NORMAL ROUTINE AND CONCENTRATION.