Engine failure ruled out as cause of fatal Essendon DFO plane crash
Engine failure has been ruled out as the cause of the plane crash into a Melbourne shopping centre that killed five men in February.
Investigators don't know what happened in the cockpit of a light plane before the fiery crash because there was no audio of the flight but say there was no evidence of engine failure.
Four Americans on a golfing holiday and a Victorian pilot died when their Beechcraft King Air small plane crashed into the nearby DFO centre soon after take-off from Essendon Airport on February 21.
The Air transport Safety Bureau (ATSB) on Wednesday released a preliminary report into the fatal crash that revealed there was no audio from the flight on the plane's black box.
The Bureau does not know why the Beechcraft King Air's black box did not record audio on its final flight, but it did on a previous trip.
"All the recovered audio was from a previous flight on January 3, 2017," the report said.
"The ATSB is examining the reasons for the failure of the [cockpit voice recorder] to operate on the accident flight."
"That examination found that the cores of both engines were rotating and that there was no evidence of pre-impact failure of either engine's internal components," the report said.
Witnesses familiar with the aircraft type reported the take-off roll along the runway was longer than normal.
After becoming airborne, the aircraft was seen to yaw left, then perform a shallow climbing left turn while maintaining a relatively level pitch and roll attitude.
The plane rolled when it hit the shopping centre roof before skidding off and coming to rest in the rear car park, the report also revealed.
The crash and post-impact fire caused considerable damage to the aircraft.
Audio recordings from air traffic control show pilot Max Quartermain repeated the word "MAYDAY" seven times shortly after take-off.
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"No additional information regarding the nature of the emergency was broadcast," the report said.
"The extensive damage caused by the collision and post-impact fire has meant investigators are yet to determine a clear picture of the causal factors behind the accident and loss of life," ATSB Chief Commissioner Greg Hood said.
Further investigation will be done on the propellers to determine the blade angles at impact, their pre-impact condition and to assess the impact damage.
The ATSB will also review witness statements, meteorological records and the plane's components, and what is left of the plane.
The final report is not due for another 12 months, but if the ATSB finds any safety issues during the investigation is has promised to immediately notify authorities and operators.
Texan retirees Greg De Haven, Russell Munsch, Glenn Garland and John Washburn died on impact when the plane hit the DFO.
