Max landing weight is in the 310,000 lbs range, and max TO weight is 410,000 lbs (+/-), depending upon operators specs.
Takeoff weight for LHR to the U.S. is probably 340,000 - 360,000 lbs.
They'd be over weight for landing but it's no big deal. The event requiring the return
would take more time to correct than the time required for an over weight landing.
Last edited by misd-agin; 24th Aug 2016 at 21:25.
Reason: Added max TO weight