‘Big loud bang’: Witnesses of horror Oakdale plane crash to assist investigators, as no survivors found in Sydney’s southwest

Witnesses have recalled the sound they heard when two light planes collided, killing three men over Oakdale, in Sydney’s southwest, about 11.50am on Saturday.

With no survivors to shed light on how the plane crash in “uncontrolled airspace” occurred, those witnesses will assist investigators to understand how the tragedy occurred, NSW Police said.

WATCH THE VIDEO ABOVE: Witnesses share details of horror plane crash.

A yellow Cessna 182, on its way to Wollongong from Cessnock, had collided in the air with a white Jabiru, a smaller plane that had just taken off from nearby Oaks Airfield.

Local resident Natasha Xuereb was inside her home when she heard the impact.

“We heard a big, loud bang, and we just went outside to have a look, and we saw thick black smoke coming from the back of our property,” Xuereb told 7NEWS.

It’s believed one of the planes fell straight down while the other landed about one kilometre away, NSW Police Acting Superintendent Timothy Calman said.

Ten ambulances and a helicopter were dispatched to the crash sites.

The impact of the crashes also set off small fires in the area.

NSW Ambulance inspector Joe Ibrahim described the scenes as “confronting” for responding paramedics.

He said there “were patients they would have liked to assist, but unfortunately there was nothing they could have done at the time.”

“The nature of the injuries were unsurvivable,” he said.

Two men were in the Cessna, and one in the Jabiru. All three are yet to be formally identified.

Air Transport Safety Bureau (ATSB) investigators headed to the crash sites on Saturday to begin their work to understand how the tragedy occurred.

NSW Police Acting Superintendent Timothy Calman said that witnesses “reported seeing debris coming from the sky.”

“Those people will be spoken to by detectives and the ATSB,” he said.

Both scenes are located near The Oaks Airfield, where the Jabiru took off just minutes before the crash.

The Sydney Recreational Flying Club operates at the airspace, but it is unknown whether either of the planes were associated with the club.

The club is also one of two flights schools which operate from the airfield, alongside Dave’s Flying School.

The pilots which use the airspace are a small, tight-knit community, 7NEWS understands.

They now join grieving family members in their hope for answers.

Investigators are now urging any witnesses who may have seen or recorded the crash to contact them via the ATSB website.