The Australian Transport Safety Bureau has released a preliminary report from its ongoing investigation into a fatal helicopter accident at Mount Disappointment, Victoria.
The report outlines factual information from the investigation’s early evidence collection phase, but contains no analysis or findings, which will be detailed in the final report.
The helicopter was one of two 7-seat EC130 helicopters operated by Microflite that departed from Batman Park Heliport in Melbourne, for a flight to Ulupna, on the NSW-Victoria border, on the morning of 31 March 2022. Each helicopter had a pilot and four passengers on board, and both were operating under visual flight rules (which permit pilots to operate only in visibility conditions generally clear enough to allow them to see where their aircraft is going).
Travelling towards Mount Disappointment, the helicopters were cruising at 3,500 ft, between a layer of scattered* cloud at an estimated 2,500-3,000 ft and a layer of broken cloud at an estimated 4,500 ft.
“As they approached Mount Disappointment, the pilot of the first helicopter noted the layer of cloud below was rising and becoming broken, while the base of the cloud above appeared to be lowering, resulting in the clouds appearing to converge ahead of them,” ATSB Chief Commissioner Angus Mitchell said.
“The pilot reported they were then confronted with a ‘wall of cloud’ in front, and to the left and right of their track, and broadcast to the other pilot their intention to turn around.”
The pilot of the first helicopter later recounted that the pilot of the second helicopter, which was trailing about 3 km behind, may have been confused by this broadcast.
The pilot of the first helicopter then broadcast ‘U-turn, U-turn, U-turn’ to the second pilot, and conducted a sharp left turn onto a southerly track.
About 30 seconds later, while travelling south at 3,650 ft, the pilot and passengers on board the first helicopter saw the second helicopter pass below and to the left of them at about 3,500 ft, continuing in a northerly direction. This was the last visual contact they had with the second helicopter.
“A short time later, before the collision with terrain, flight track data showed the second helicopter in a left descending turn,” Mr Mitchell said.
The ATSB’s survey of the accident site subsequently determined that the helicopter collided with a large old growth tree trunk before impacting the ground about 250 m south of the last recorded data point. All five occupants were fatally injured.
Much of the wreckage was destroyed by a post-impact fire, however, investigators found no evidence of any pre-existing defects that would have affected the helicopter’s operation.
As well as site survey activities, to date ATSB investigators have also interviewed the pilot of the first helicopter, the operator’s chief pilot, and collected passenger statements, operational and maintenance data, onboard recording equipment, and meteorological data.
“As the investigation continues the ATSB will attempt to download and analyse data from the helicopter’s onboard Appareo camera, which may have recorded video and audio of the accident flight, plus the pilot’s iPad, which was being used to run an electronic flight bag flight planning app, as well as avionics equipment from the helicopter,” said Mr Mitchell.
Investigators will also analyse other aspects relevant to the accident including the weather data, the helicopter’s maintenance history, the pilot’s qualifications and experience, witness information, the operator’s management systems, and the training and flight review standards for commercial helicopter pilots.
“While a final report will be released at the conclusion of this investigation, should a critical safety issue be identified at any time, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken,” Mr Mitchell concluded.
* Cloud cover: ‘scattered’ indicates that cloud is covering between a quarter and a half of the sky, ‘broken’ indicates that more than half to almost all the sky is covered.Last update 12 May 2022