AN ACR FO RPT REGARDING HIS TKOF DATA COMPUTATIONS AT ANC; AK. RWY 14 DID NOT ALLOW A MAX TKOF WT FOR HIS ACFT WITH A 10 KT HEADWIND. RWY 24L; 800 FT SHORTER WITH A XWIND; DID.

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ACFT LOADING CALLED FOR A MAX ALLOWABLE TKOF WT OF 160000 LBS (ACFT STRUCTURAL LIMIT). ACFT WAS FULL OF PAX; FUEL; AND FREIGHT. WE CONSULTED THE ACFT PERFORMANCE BOOKS AND FOUND OUT THAT WE COULD NOT USE THE LONGEST RWY WITH A DIRECT HEADWIND. A CALL TO COMPANY DISPATCH RESULTED IN US VERIFYING WE COULD USE A SHORTER RWY WITH A XWIND. CONSIDERING POSSIBLE ENG FAILURES AT MAX GROSS WT AND TERRAIN CONSIDERATIONS; THE DECISION WAS MADE TO GO OUT W OVER WATER WITH NO OBSTRUCTIONS. THE TKOF RUN WAS VERY LONG AND AFTER WE WERE AIRBORNE; PERFORMANCE WAS SLUGGISH. ALL THIS TO BE EXPECTED. WHAT BOTHERS ME ABOUT THIS ABNORMAL TKOF IS WE COULDN'T USE THE LONGEST RWY; THAT WAS DIRECTLY INTO THE WIND (RWY 14; WIND 140 DEGS AT 10 KTS; GUSTING TO 17 KTS); AND DOWNHILL (.03%) SLOPE; TO LIFT 160000 LBS INTO THE AIR. THE 'DATA' SHOWS THAT WE CAN LIFT 160000 LBS INTO THE AIR OFF A SHORTER RWY (RWY 24L) WITH A 90 - 100 DEG WIND CROSSWIND/TAILWIND; WITH A .03% UPSLOPE. AND THAT JUST DOESN'T SEEM CORRECT TO ME. I PLAN TO GET TOGETHER WITH MY COMPANY GND SCHOOL PERFORMANCE INSTRUCTORS AND MAKE SURE OUR CALCULATIONS WERE CORRECT.