Engineers assisting the accident investigation calculated that for the wing spar to fail in the way it did in VH-TVC would require the aircraft to be flying faster than its maximum speed of and , while being subjected to a severe recovery manoeuvre by the crew , to encounter a very strong gust , possibly as much as . At the time of the accident investigation , gusts up to had been measured inside thunderstorms by suitably equipped research aircraft . Investigators were aware of the crash of Capital Airlines Flight 75 , a Vickers Viscount that crashed in Maryland , USA in May 1959 after encountering extreme turbulence associated with thunderstorms
Capital Airlines Flight 75
Capital Airlines Flight 75
Ansett-ANA Flight 325