A pilot has been killed in WA’s Wheatbelt while test flying a light plane he built.

Emergency crews responded to the incident, involving an amateur-built replica Spitfire aircraft, in Malabaine, north of Northam, about 10.50am Wednesday.

DFES, St John Ambulance and WA Police responded to the crash.

The 76-year-old man, who was the sole occupant of the aircraft, was found dead at the scene.

Police say the plane appears to have been found in bushland off Great Eastern Highway, with the nearest cross street being Yilgarn Avenue.

The Northam airport is a few kilometres from where the plane crashed.

Police say a report will now be prepared for the coroner.

The fallen aircraft was painted to honour RAAF Squadrons 457 and 453.

Facebook page Whitsunday Spitfire confirmed the plane was the one involved in the crash while doing flight testing on Wednesday.

“Some sad news — our friend had a fatal crash in his MK26B Spitfire near Northam today conducting flight testing after he built it. We don’t know much yet but thought I’d let you know that it wasn’t me,” a post on the page read.

The man behind the post did not wish to comment on the incident.

The Australian Transport Safety Bureau (ATSB) confirmed Wednesday afternoon it is investigating the crash, which it says was being used for a “private flight when it collided with terrain”.

“The ATSB has deployed a team of transport safety investigators from its Canberra offices, specialising in aircraft maintenance and engineering, and materials analysis,” the national transport safety investigator said in a statement.

“They will arrive on site on Thursday, and over coming days will conduct a range of evidence-gathering activities, including site and wreckage examination, and recovery of any aircraft components of interest for further examination at the ATSB’s technical facilities in Canberra.”

Investigators will interview witnesses and involved parties, and collect relevant recorded information including any available flight tracking data, as well as pilot and aircraft maintenance records and weather information.

Members of the public with footage of the flight, crash or aftermath, are urged to contact the agency here.

The ATSB is expected to publish a preliminary report in about eight weeks, with a final report to be released when the investigation has concluded.

Any critical safety issues will be flagged immediately, the agency said.