Widebody transport crew took off using company calculations, apparently the calculations were wrong.

Attributes
ACN	497170
Time
Date	200101
Day	Tue
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : vabb.airport
State Reference	FO
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	ground : parked
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 10000
ASRS Report	497170
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	non adherence : published procedure
Independent Detector	other other : dispatcher
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Company Flight Crew Human Performance
Primary Problem	Company

Narrative:

Tower reported calm winds on ATIS. On taxi out to runway 27, tower reported various winds from 360 degrees to 040 degrees at 2-6 KTS. We cleared runway, and asked company via ACARS, station operations for maximum takeoff weight with 20 degrees C 29.87 altimeter and 2 KTS of tailwind. Company replied with multiple variations, but not those requested. After 1 hour and threat of shutting down flight, over HF company stated 556.3 when tower reported steady state of winds below 2 KTS we took runway to back taxi and after 180 degree turn tower confirmed less than 2 KT tailwind so we took off. We had burned contingency on the ground to reach maximum takeoff weight. Approximately 5 hours into flight, company amended maximum takeoff weight over ACARS and used less fuel on gross weight page than we originally had or had after burning off contingency fuel to the maximum takeoff weight they had specified over HF. Also, station operations said we were good to go when our weight was over maximum takeoff weight and they claimed it was ok from company dispatch who was not using the 2 KT tailwind.

Original NASA ASRS Text

Title: WDB CREW TOOK OFF USING COMPANY CALCULATIONS, APPARENTLY THE CALCULATIONS WERE WRONG.

Narrative: TWR RPTED CALM WINDS ON ATIS. ON TAXI OUT TO RWY 27, TWR RPTED VARIOUS WINDS FROM 360 DEGS TO 040 DEGS AT 2-6 KTS. WE CLRED RWY, AND ASKED COMPANY VIA ACARS, STATION OPS FOR MAX TKOF WT WITH 20 DEGS C 29.87 ALTIMETER AND 2 KTS OF TAILWIND. COMPANY REPLIED WITH MULTIPLE VARIATIONS, BUT NOT THOSE REQUESTED. AFTER 1 HR AND THREAT OF SHUTTING DOWN FLT, OVER HF COMPANY STATED 556.3 WHEN TWR RPTED STEADY STATE OF WINDS BELOW 2 KTS WE TOOK RWY TO BACK TAXI AND AFTER 180 DEG TURN TWR CONFIRMED LESS THAN 2 KT TAILWIND SO WE TOOK OFF. WE HAD BURNED CONTINGENCY ON THE GND TO REACH MAX TKOF WT. APPROX 5 HRS INTO FLT, COMPANY AMENDED MAX TKOF WT OVER ACARS AND USED LESS FUEL ON GROSS WT PAGE THAN WE ORIGINALLY HAD OR HAD AFTER BURNING OFF CONTINGENCY FUEL TO THE MAX TKOF WT THEY HAD SPECIFIED OVER HF. ALSO, STATION OPS SAID WE WERE GOOD TO GO WHEN OUR WT WAS OVER MAX TKOF WT AND THEY CLAIMED IT WAS OK FROM COMPANY DISPATCH WHO WAS NOT USING THE 2 KT TAILWIND.

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.