The airport quickly became Becoming congested with parked Placing airplanes blocking Hiding_objects the only taxiway and forcing Hostile_encounter departing aircraft to taxi on the runway instead .

The collision occurred Coming_to_be when the KLM airliner initiated Process_start its takeoff Self_motion run while the Pan Am airliner , shrouded Hiding_objects in fog , was still on the runway and about to turn off Motion onto the taxiway .