The pilots failed Agree_or_refuse_to_act to switch Change_tool on the engines ' internal ice protection systems , used Using reverse thrust in a snowstorm prior to takeoff Self_motion , tried to use Using the jet exhaust of a plane in front of them to melt their ice , and failed Earnings_and_losses to abort Process_end the takeoff Motion even after detecting Check a power problem while taxiing and seeing Perception_active ice and snow buildup Cause_change_of_position_on_a_scale on the wings .

The National Transportation Safety Board ( NTSB ) concluded Coming_to_believe that the flight crew were unaware of the amount of ice that had built Building up after the jet was delayed Change_event_time by heavy ground traffic taxiing to the runway .