catastrophic inflight breakup due to a phenomenon known as mast bump which caused the main rotor blades to come in contact with the fuselage and cockpit
2020-03-28 [2020-03-29]. (原始内容存档于2020-04-02) (中文(繁體)). Butz, Melissa. With half-mast flags, Vatican joins Italy in moment of silence for COVID-19 victims. Rome