Medium Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Last 90 Days 25; Flight Crew Total 12000; Flight Crew Type 500
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Human Factors; Procedure
Taxi out our weight was 491500.  We had to do a gate return to remove 2 deportees and an escort for security reasons.  We came back to the gate and removed 3 pax.  We waited for the final weight manifest showing 3 less pax.  The new FWM came back saying we weighed 275;000 pounds.  V speeds were approx 30 kts less.  Captain called dispatch to fix the numbers and we got printed messages saying that the aircraft was properly balanced.  This error if not caught by the crew could have resulted in a total hull loss and several deaths.
After leaving gate; load planning changed aircraft (AC) weights numerous times which changed takeoff (TO) speeds. TO speeds would not load so we called load planning to send new speeds; no help with auto load after numerous sending of AC weights. Called Load planning chief again for TO speeds and finally sent a msg. with our speeds; and the speeds were way off. 134;136;148 for a AC weight of 490.0 We all questioned the speeds and called Load Planning again saying these speeds are way too low for this AC Later we got a msg. saying 'what are you referring to you are perfectly balanced'. We were referring to speeds that would have caused a tail strike or worse if we used them. We received the proper speeds just prior to the msg. questioning our calls. 162;163;169. We were at the hold short line when we received the numbers and if we had not had a passenger issue we may not have caught the error.
Flight crew reports receiving final weights and V Speeds for an aircraft weighing 275K while the manifest indicated a gross weight of 490K. Multiple contacts with load planning are required to straighten the problem out with the new V Speeds being 30 knots higher than those initially provided.