Air Florida Flight 90 was a scheduled domestic flight that crashed shortly after takeoff from Washington National Airport on January 13, 1982. The aircraft, a Boeing 737, encountered severe icing conditions, which affected its performance. It struck a bridge and fell into the Potomac River, resulting in the deaths of 78 people, including four motorists on the bridge. The accident prompted significant changes in aviation safety regulations, particularly regarding de-icing procedures and pilot training. Investigations revealed that the flight crew did not adequately remove ice from the wings before takeoff, highlighting the importance of proper pre-flight checks in adverse weather conditions.