from the report
Air traffic control procedures
Air traffic controllers are able to issue clearances for visual approaches when flight crew have established and can continue flight to the airport with continuous visual reference to the ground or water and with visibility at least 5 km. Once an air traffic controller clears a crew to conduct a visual approach, the crew has responsibility to maintain separation from terrain and, in the case of the occurrence flight, remain at least 500 ft above the lower limit of controlled airspace.
After the occurrence, the air traffic service provider (Airservices Australia) advised that the minimum safe altitude warning system (MSAW) had been inhibited in certain areas to the north-east of Melbourne to reduce the number of false alarms in those areas. In addition, Airservices Australia advised that when a flight is cleared for a visual approach its corresponding cleared flight level is set to 000 (ft) on the controller’s air situation display. As a result, the system automatically inhibits the MSAW aural alarm and display for that flight.
Really, is this good enough?
Minimum safe altitude warning system (MSAW) had been inhibited in certain areas to the north-east of Melbourne to reduce the number of false alarms in those areas.
Why not fix the software to reduce the number of false alarms?
Why not develop SOP to reduce the likelihood of false alarms?
Was a safety alert issued by the controller?
Swiss cheese anyone?