USAir submitted to the NTSB that pilots should receive training with regard to a plane 's crossover speed and recovery from full rudder deflection . As a result , pilots were warned of and trained how to deal with insufficient aileron authority at an airspeed at or less than , formerly the usual approach speed for a Boeing 737 . Boeing maintained that the most likely cause of the crash was that the co-pilot inadvertently deflected the rudder hard-over in the wrong direction while in a panic and for unknown reasons maintained this input until impact with the ground . Boeing agreed to redesign the rudder control system with a redundant backup and paid for the retrofit of the entire worldwide 737 fleet . As one of the NTSB 's main recommendations , airlines were required to add four additional channels of information — pilot rudder pedal commands — into flight data recorders , with which the FAA gave airlines until August 2001 to comply . In 2016 , former investigator John Cox stated that time so far has proven the NTSB correct in their findings due to the absence of a rudder reversal incident since Boeing 's redesign . Following the airline 's response to the Flight 427 accident , the United States Congress required airlines to deal more sensitively with the families of crash victims . USAir ceased using Flight 427 as a flight number . Flight 427 was the second fatal USAir crash in just over two months , the other being Flight 1016 at Charlotte-Douglas Airport in July 1994 . The crashes contributed to the financial crisis USAir was experiencing at the time
Flight 1016
USAir Flight 1016
USAir Flight 427