Narrative:

Because the wrong take-off weight was entered into the ACARS runway analysis system (ras); the calculated thrust and speed was incorrect. 597;000lbs was entered instead of the actual take-off weight of 827;311 lbs. After entry of the wrong take-off thrust setting; the FMC calculated speed on the takeoff page was showing dashed lines (unavailable) instead of FMC calculated V speeds which usually provide the flight crew with a chance of double checking the value. The speeds on the ras print out were; instead; inserted manually. During take-off; the aircraft was rotated earlier than the vr for the actual weight; which caused ground contact after slight lift off; followed by stick shaker. We suspected encountering wind shear and performed wind shear escape maneuver with maximum thrust. During climb out; after a brief discussion; we could not preclude the possibility of a tail strike; therefore the following consideration was given: checked that all systems including pressurization were showing normal; contacted ZZZ tower to check for any sign of damage or debris on the runway; to which ZZZ later replied with 'negative'; contacted maintenance control to confirm the aircraft status; the result of which showed no abnormal readings. After we reviewed all the paper work; the wrong takeoff weight entry was identified; hence; we monitored all systems -- engine and cabin pressure readings in particular -- throughout the flight and kept close contact with the company. For the concern of safety; we selected a lower cruising altitude and performed an auto land; with a safe landing ensuing at our destination.

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Original NASA ASRS Text

Title: A B747-400 flight crew took off with manually calculated V speeds; based on a TOGW 230;000 pounds less than the actual weight. A possible tail strike and failure to lift off at the lower Vr speed was overcome only by initiating the windshear escape maneuver using firewall/maximum thrust.

Narrative: Because the wrong take-off weight was entered into the ACARS Runway Analysis System (RAS); the calculated thrust and speed was incorrect. 597;000lbs was entered instead of the actual take-off weight of 827;311 lbs. After entry of the wrong take-off thrust setting; the FMC calculated speed on the takeoff page was showing dashed lines (unavailable) instead of FMC calculated V speeds which usually provide the flight crew with a chance of double checking the value. The speeds on the RAS print out were; instead; inserted manually. During take-off; the aircraft was rotated earlier than the Vr for the actual weight; which caused ground contact after slight lift off; followed by stick shaker. We suspected encountering wind shear and performed wind shear escape maneuver with MAX thrust. During climb out; after a brief discussion; we could not preclude the possibility of a tail strike; therefore the following consideration was given: Checked that all systems including pressurization were showing normal; contacted ZZZ tower to check for any sign of damage or debris on the runway; to which ZZZ later replied with 'negative'; contacted Maintenance Control to confirm the aircraft status; the result of which showed no abnormal readings. After we reviewed all the paper work; the wrong takeoff weight entry was identified; hence; we monitored all systems -- engine and cabin pressure readings in particular -- throughout the flight and kept close contact with the company. For the concern of safety; we selected a lower cruising altitude and performed an auto land; with a safe landing ensuing at our destination.

Data retrieved from NASA's ASRS site as of April 2012 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.