Could also be in breach of CASR Part 91.685,
91.685 reads:(1) The pilot in command of a multi‑engine aircraft for a flight contravenes this subregulation if, during the flight:
(a) an emergency occurs that threatens the safety of the aircraft or the persons on the aircraft; and
(b) the pilot does not land at the aerodrome that is, in the circumstances, the nearest suitable aerodrome for the aircraft to land at.
Is it an emergency that fits that requirement of aircraft or occupant safety being threatened?
As was shown, the aircraft flew quite capably from Adelaide to Essendon.
Not until the aircraft touches down does the safety concern/threat arise so, until that touchdown happens, there is no emergency. An abnormal situation, certainly, but not an emergency.