Aircraft Accident Investigation Bureau (AAIB, German: Büro für Flugunfalluntersuchungen, BFU; French: Bureau d'enquête sur les accidents d'aviation, BEAA; Italian: Ufficio d'inchiesta sugli infortuni aeronautici, UIIA) was the Swiss bureau of aircraft accident investigation. In 2011, it was replaced by the Swiss Transportation Safety Investigation Board.