The ATSB is investigating two occurrences involving Airbus A380 aircraft descending below minimum assigned altitude.

During both occurrences, after receiving clearance for the runway 34 RNP approach, the aircraft descended below the required altitude restriction of A030 and out of controlled airspace. In each case the controller alerted the flight crew, and the aircraft was monitored by air traffic control to ensure it remained clear of traffic until re-established inside controlled airspace.