A minority report stated Statement that the accident could have been caused Causation by an onboard explosion Catastrophe of unknown origin prior to impact , with one of these dissenting investigators later telling Telling a United States congressional committee that it was impossible for a thin layer of ice to bring down the aircraft .

The dissenting report Reporting led to delays Change_event_time in changes Change to de-icing procedures , with a thin layer of ice causing Causation the deadly crash Catastrophe of Air Ontario Flight 1363 in Canada in 1989 .

Steered by a deep layer high over Mexico , the disturbance moved Motion west for four days before becoming a tropical depression on September 27 off the southwest coast of Mexico .

By then , snow was falling Motion_directional , causing Causation a layer of slush to form Coming_to_be at the end Process_end of the runway .