MD80 FLC DEPARTS GEG OVERWT.

Narrative

AFTER DEP (PUSHBACK) GND OPS AGENT ADVISED THAT SHE HAD TO GET US AN AMENDED RELEASE DUE TO MORE WT. THIS IS ALWAYS DONE AFTER PUSHBACK AND USUALLY JUST TAKES 1-2 MINS. WE HAD EXPERIENCED DIFFICULTY REACHING DISPATCH AND IT SEEMED THAT SHE WAS ALSO HAVING DIFFICULTY CONTACTING DISPATCH. THERE WAS NO URGENCY IN ANY OF THIS SINCE IT IS A COMMON OCCURRENCE AND THE AMENDMENTS ARE GIVEN AFTER AIRBORNE SOMETIMES. AT NO TIME WAS IT MADE CLR TO DELAY TKOF. THE FO WAS NEW AND HAD JUST GONE OVER 100 HRS IN TYPE AND THIS WAS HER FIRST JET FLYING. THE FO MISSED THE FACT THAT THERE WAS A 7000 LB DIFFERENCE BTWN RELEASE AND ACTUAL TKOF WT. A NEW FLT PLAN IS REQUIRED FOR MORE THAN 5000 LBS DIFFERENCE AT OUR COMPANY. WE HAD REACHED THE END OF THE RWY AND WERE GIVEN A TKOF CLRNC; SO WE TOOK OFF. AFTER AIRBORNE; THE OPS AGENT WAS DISTRESSED TO FIND OUT WE WERE IN THE AIR. SHE THEN STATED THAT NO AMENDMENT WOULD BE ISSUED BECAUSE WE NEEDED A NEW FLT PLAN ALSO. THERE WAS NO WAY SHORT OF TAXIING BACK TO THE GATE TO GET A NEW FLT PLAN. THE FLT WAS ABOUT 50 MINS TO SEATTLE AND WE HAD 3000 LBS EXTRA FUEL.