On 9 December 2010, a Cessna 404 aircraft, registered VH-XDA, was being operated on a charter passenger flight from Century Mine to Mount Isa, Queensland.
Shortly after departing, the pilot noticed that there was no output from the right alternator. The pilot turned the right alternator off and continued the flight.
While maintaining 9,000 ft, the pilot noticed that the right engine oil pressure gauge was indicating zero. At the time, the pilot believed that the gauge was faulty. A descent to 5,000 ft was commenced as a precaution.
During the descent, the right engine shut down. The pilot heard a loud bang and observed smoke emanating from the engine. The pilot actioned the emergency procedures checklist and commenced a diversion to the Mount Gordon aeroplane landing area (ALA). The aircraft landed without further incident.
A subsequent engineering examination determined that the alternator drive coupling on the right engine had failed.
As a result of this incident, the aircraft operator advised the ATSB of their intention to amend the maintenance schedule for aircraft fitted with Teledyne Continental Motors engines and gear driven alternators. By reducing the existing inspection interval of up to 500 hours, to at or before 220 hours.