By Cameron Myles and Heather McNeill

Two crew members managed to free themselves after a Boeing 737 water bomber crashed while fighting a fire along Western Australia’s southern coast on Monday afternoon.

The plane, a Boeing 737 Fireliner National Large Air Tanker, crashed in the Fitzgerald River National Park about 4.15pm just after dropping a load of fire retardant on the blaze.

It had taken off from the Busselton-Margaret River Regional Airport, where it is stationed, at 3.30pm before crashing at the fire ground.

A bushfire watch and act warning is currently in place as firefighters battle a blaze which has already burnt more than 900 hectares in the national park, which is about a six-hour drive from Perth in the state’s Great Southern region.

Upstream Aviation owner Tim Collins said large air tankers assisting with firefighting efforts typically flew in very difficult conditions.

“The logistics of flying a large aircraft close to the ground in those kinds of conditions is extremely challenging,” he said.

“You’re flying at a fairly slow speed, you can’t fly too fast otherwise the fire retardant will disappear out the back, and you get severe temperature updrafts and downdrafts and wind shear.”

Collins said if the plane had stalled midair it may not have had the height or speed needed to recover.

In 2020, three US crew onboard a C-130 large air tanker died after the plane stalled midair due to wind shear and tailwinds. The trio were in the Snowy Mountains assisting with NSW firefighting efforts at the time.

Flight tracking information showed the WA plane was travelling at 675 feet at a speed of 101 knots just before it crashed.

A Department of Fire and Emergency Services spokesman said the WA plane’s two occupants managed to free themselves after the unplanned landing and were airlifted to Ravensthorpe Airport by a nearby firefighting helicopter.

An Australian Maritime Safety Authority spokesman said the authority was tasked with sending a helicopter to help, but before it could arrive the survivors had been rescued.

There were no other crew aboard the firebomber when it crashed.

The two crew members were taken the local medical centre for treatment to minor injuries and the Royal Flying Doctor Service has mobilised a team to bring them to Perth if required.

Officers from the Australian Transport Safety Bureau will attend the crash site to begin their investigation when possible.

The state government announced the Boeing 737 Fireliner’s arrival in WA in December, revealing the large air tanker used to fight Californian wildfires would be based in Busselton over the high-threat fire season.

Nicknamed “Phoenix”, the plane boasts the capacity to carry 15,000 litres of fire suppressants and has a loaded cruising speed of nearly 800 kilometres an hour.

By the time the government announcement came out, the 737 had already been put to work to douse a fire threatening Cervantes and Jurien Bay in mid-December.

It is one of two National Large Air Tankers stationed in Busselton, with a C130 Hercules also based at the South West airport.