Four people killed in horror Melbourne plane crash
A plane has crashed near Seymour with at least one person on board. (Nine)
Four people have died after two planes collided mid-air before crashing into a paddock in Melbourne's north this morning.
Emergency services, including police and paramedics, were called to the scene at 11.30am following reports of two separate aircraft crashes.
The crash site was about seven kilometres south from a flight training school at Mangalore, near Seymour
Nine News understands the aircraft's were both in flight training at the time of the crash.
The two occupants in each aircraft died at the scene.
Officers are in the process of notifying the family members of the four people.
"We're not sure why both aircraft were on the same trajectory," Mitchell Local Area Commander Inspector Peter Koger said.
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"Unfortunately they collided mid-air."
One plane, a Piper-Seminole aircraft operated by flying school Moorabbin Aviation Services, had a trainee and instructor on board.
The aircraft had just taken off from Mangalore airfield and reached 1200 metres, when it collided with a Beechcraft Travel Air.
The second plane had a pilot and instructor on board from Peninsula Aero Club.
Workers witnessed the mid-air collision whilst doing electrical cabling in a paddock at a Defence Force secure site.
Aerial images of the scene taken from the 9News helicopter show debris from the two planes scattered across grassland.
Victoria Police Leading Senior Constable Kendra Jackson said the Civil Aviation Safety Authority (CASA) and the Australian Transport Safety Bureau (ATSB) had been notified.
"Police are currently investigating and will prepare a report for the Coroner," she said.
Both planes had clearance to be in the airspace, but whether they had radio contact prior to the collision is still unknown.
Investigators from the ATSB are set to comb through logbooks and maintenance records as part of the investigation.
In a statement, the ATSB said an investigation into the cause of the collision was underway.
"Transport safety investigators with experience in human factors, aircraft operations and maintenance from the ATSB's Melbourne, Canberra and Brisbane offices are preparing to deploy to the accident site," it read.
"On site, investigators will examine the wreckage and site surrounds.
"The ATSB will also analyse available recorded data, review weather information, and interview witnesses."