Four people have died after two light planes on training flights crashed mid-air near a regional Victorian airport.
Emergency services were called to two separate crash scenes near Mangalore Airport about 11.30am on Wednesday, finding the aircraft a few kilometres from each other.
The bodies of all four people, yet to be formally identified, were found in the wreckage.
It is understood one man aged in his 30s and another in his 40s were on one of the planes, a privately-owned Beechcraft Travel Air D95A operated by the Peninsula Aero Club at Tyabb.
The two men were qualified as instructors and were conducting a training flight, Peninsula Aero Club president Jack Vevers said.
"It's devastating, they are dear people to us, they're friends, they're colleagues. We're all as a community quite devastated by this news," he said.
The Civil Aviation Safety Authority said the other plane was a Piper Seminole twin engine registered to Moorabbin Aviation Services, also on a training flight.
Mitchell Local Area Commander Inspector Peter Koger said there were witnesses to the planes colliding and one of the aircraft coming down.
"One plane almost certainly crashed immediately and the other plane crashed about two kilometres north from here and both were extensively damaged prior to colliding with the ground," he told reporters.
"There were some people in the paddocks at the back of this facility and there was also a helicopter in the air and we're working with them to get witness statements," he said.
CASA and the Australian Transport Safety Bureau will investigate the crash, with ATSB investigators from Melbourne, Canberra and Brisbane preparing to head to the crash site
"The investigators that are deploying to the accident site have experience in human factors, aircraft operations and maintenance," ATSB Transport Safety executive director Nat Nagy said.
"Once they arrive on site the investigators will be looking at the aircrafts' wreckage as well as the site surrounds. The ATSB will also analyse available recorded data, review weather information, and interview witnesses."
Mangalore Airport is open to recreational flyers and those learning to fly, and is also used by state and federal government departments.
Mangalore Airport and Moorabbin Aviation Services declined to comment.
Australian Associated Press