Police have confirmed two people have been killed in the small aircraft crash off Forrest Beach.
The aircraft was travelling along the shoreline of Forrest Beach between Capel and Busselton when it crashed at 2.20pm.
Inspector Steve George addressed media at the scene and said it was a privately-owned gyroplane that crashed into the water about 10 metres off shore.
“We are covering the plane at the moment,” he said.
“What the police will do now is recover it from the water and prepare a report for the coroner and the Federal Air transport authorities will conduct an investigation.
“We had a witness say they observed the gyroplane about 200 metres in the air and it crashed into the water.
“Tomorrow we’ll get police divers to come and have a look and search the ocean looking for parts of the aircraft.
Inspector George said they were hoping to remove the aircraft from the water in the next couple of hours.
WA Police spokesman Samuel Dinnison said police and other emergency responders were at the scene.
"Several police vehicles and other emergency responders were deployed the scene," he said.
"The aircraft appears to be a small helicopter-type aircraft – the exact make and model is not yet confirmed."