Firebomber with two people on board crashes in Western Australia

A fire-fighting plane has crashed in Fitzgerald River National Park south of Ravensthorpe in Western Australia.

The Boeing 737 Airliner had been fighting fires in the area when the plane went down about 4.15pm (7.15pm AEDT), the Western Australian Department of Fire and Emergency Services (DFES) confirmed on Monday evening.

Two people on board the plane managed to escape.

READ MORE: Calls for cull as friends and family mourn WA teen mauled by shark

A helicopter airlifted them to Ravensthorpe Airport before they were taken to a local medical facility.

The Australian Maritime Safety Authority (AMSA) said it "detected an emergency beacon activation from the firebomber" approximately 185 kilometres west of Esperance.

READ MORE: Man charged after horror boat crash claims two women's lives

"There were no other crew aboard the firebomber when it crashed," AMSA said in a statement issued on Monday evening.

Coulson aviation group, who owned the 737 FireLiner said they were "very grateful the two team members on Tanker 139 are safe".

"Both pilots walked away from the accident, and have been medically assessed," they said in a statement on Monday night.

"Our thoughts and our immediate concern is for those team members and their families."

The National Large Air Tanker had departed Busselton-Margaret River Airport, bound for the bushfire, about 3.30pm today, 45 minutes before the crash.

The Australian Transport Safety Bureau has launched an investigation into the accident.

A team of investigators from Perth and Canberra is heading to the crash site to recover data and evidence.

Sign up here to receive our daily newsletters and breaking news alerts, sent straight to your inbox.