The NTSB determined that all three incidents could only be explained by pilot error or a malfunction of the rudder system, and based partly on post-accident interviews with the Flight 517 pilots, concluded that rudder malfunctions were likely to have caused all three incidents.
A NTSB determinou que os tres incidentes só podían ser explicados por un erro do piloto ou polo mal funcionamento do sistema do timón, e baseandose en parte nas entrevistas posteriores cos pilotos do voo 517, concluíu que os fallos do timón poderían ter causado os tres incidentes.