Narrative:

Aircraft loading called for a maximum allowable takeoff weight of 160000 pounds (aircraft structural limit). Aircraft was full of passenger, fuel, and freight. We consulted the aircraft performance books and found out that we could not use the longest runway with a direct headwind. A call to company dispatch resulted in us verifying we could use a shorter runway with a crosswind. Considering possible engine failures at maximum gross weight and terrain considerations, the decision was made to go out west over water with no obstructions. The takeoff run was very long and after we were airborne, performance was sluggish. All this to be expected. What bothers me about this abnormal takeoff is we couldn't use the longest runway, that was directly into the wind (runway 14, wind 140 degrees at 10 KTS, gusting to 17 KTS), and downhill (.03%) slope, to lift 160000 pounds into the air. The 'data' shows that we can lift 160000 pounds into the air off a shorter runway (runway 24L) with a 90 - 100 degree wind crosswind/tailwind, with a .03% upslope. And that just doesn't seem correct to me. I plan to get together with my company ground school performance instructors and make sure our calculations were correct.

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Original NASA ASRS Text

Title: 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.

Narrative: 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.

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.