A history buff and a helicopter pilot believe they have solved the mystery surrounding the final resting place of an RAAF aircraft which crashed into the ocean off Broome almost 70 years ago.
The Beaufighter A19-163 plummeted into the Indian Ocean just after take-off from Broome airfield at 4.35am on September 18, 1944.
The crash killed the pilot, Flight-Sgt Ronald Kerrigan, 20, of North Perth, and Sgt Ronald Smith, the navigator, from Strathfield, NSW.
Dion Marinis, the vice-president of the Broome Historical Society, and local chopper pilot Jim Miles began searching for the lost plane in 2012.
Mr Marinis said yesterday they had used his 4.3m "tinnie" to tow a homemade side-scan sonar that Mr Miles had made, before using a more sophisticated scanner and also a metal detector.
They gradually found parts of what they believe is the missing plane, including a window frame, which they had matched with a Beaufighter at Moorabbin Aviation Museum, as well as the tail wheel, tail plane and part of a wing.
About three weeks ago they found an engine, in about 12m of water, and Mr Marinis said at the weekend they had found more wreckage, including a 20mm cannon and the second engine.
Mr Marinis said they had notified the RAAF and the WA Maritime Museum about their find.
The men have received correspondence from the museum that supports their belief that they have found the missing plane.
"From what we can gather it went in at a fairly steep angle," Mr Marinis said.
The Court of Inquiry had found that while the cause was unknown, "without prejudice to the crew of the aircraft, that it occurred through poor technique on the part of the pilot due to lack of experience in the particular type of aircraft".
Mr Marinis said he and Mr Miles disagreed with the Court of Inquiry finding, after examining in-depth witness accounts that were part of the crash investigation.
"As a helicopter pilot, from the evidence we have studied and the manner in which the aircraft impacted, we are of the opinion the left-hand engine caught fire and exploded on take-off, subsequently causing a disaster," Mr Miles said.
"The instrumentation that the pilot had was minimal, on a pitch dark night, with an exploding engine on fire out the pilot's left window that would have caused confusion and disorientation."
Mr Marinis contacted Flight-Sgt Kerrigan's sister Val Bullied, of Scarborough, to let her know of the find.
Yesterday, Mrs Bullied said she had been a teenager when her brother disappeared and his loss had been heartbreaking.
She said it was wonderful that it seemed the aircraft had been found.
Mr Marinis said he hoped to be able to trace the family of Sgt Smith and also had suggested that the Shire of Broome erect a memorial to the airmen on Cable Beach.
He hoped it would be possible to have the memorial in place for a service to commemorate the two airmen on September 18 to mark the 70th anniversary of their death.