They didn't have the right licenses, they didn't use the right procedures and they flight planned to a closed airport. Then they crashed the plane. Other than that Mrs. Lincoln, they did a terrific job.
The closed airfield was notified in a new NOTAM which did not reach the FAWB controller until after the flight
had departed.
They had valid Australian licenses which had not been fully validated for the SA registered aircraft. A paperwork issue.