On 20 December 2009 an aircraft almost stalled at high altitude after the crew attempted to continue climbing beyond the maximum available altitude at the prevailing aircraft weight. The Investigation found that failure to cross check data input to the Performance Management System prior to take off had allowed a gross data entry error made prior to departure - use of the Zero Fuel Weight in place of Gross Weight - to go undetected.

http://eurocontrol.us1.list-manage.com/track/click?u=0fa4593636877e9fd022bcdc1&id=abb0ca8f67&e=f23d274685