Some time into the flight, while cruising at 37,000ft, a failure in the No.1 ADIRU led to the autopilot automatically disengaging followed by two sudden uncommanded pitch down manoeuvres, accrding to the Australian Transport Safety Bureau (ATSB).
Some time into the flight, while cruising at 37,000ft, the plane experienced a "sudden change in altitude" followed by a nosedive of 197 meters, that injured 51 passengers and crew. The incident was linked to a failure in the ADIRS in an initial report by the Australian Transport Safety Bureau (ATSB).