As the aircraft (registered ZK-OKN) was tracking to land on runway 01, it had been cleared to descend to 3,000ft but was observed to have descended to 2,500ft. The crew were alerted to this, but the aircraft continued to descend to 2,000ft.
The ATSB has classified the event as an operational incident and will review recorded data, interview the flight crew and gather additional data. The investigation is expected to be complete by April 2018.
(Ellis Taylor - FlightGlobal News)