It was no throwaway line: as an RAAF pilot during World War II, he repeatedly faced death fighting Japanese invaders over Darwin.

On June 30, 1943, as his squadron scrambled to intercept up to 48 enemy planes, Flight Sergeant Duncan's faulty Spitfire overheated and caught fire.

The lever to open the cockpit canopy broke off and it was only after Duncan kicked and battered it, with fire licking at his legs, that it came free. With the plane in a spiral dive, he ejected and parachuted to the ground.

Suffering severe burns to his arm and knees, Duncan survived in the bush for four days before being rescued.

After the war he worked as a builder, then architect and inventor. He married and had two daughters. He died of cancer, age 73, in 1992.

But in an unexpected coda, last Thursday, a Northern Territory government official informed Duncan's Victorian family that the Spitfire wreck had been found, in a remote corner of Litchfield National Park.

A helicopter pilot spotted it in March, but it took months for the RAAF to confirm it as Duncan's – ID number A58-2 – via databases of WWII crashes, and a trip to the site by helicopter.

Mrs Duncan, 90, of Dromana, said it was closure on an incident that scarred her husband for life. He would relive the moment "when he realised he still had his parachute and he wasn't on fire". But there was little psychological help.

She believes the trauma contributed to his nervous breakdown in the late 1960s, following the death of his brother, Jack, and the burden of running the family building company.

Grandson Duncan Williams, 40, of Reservoir, said the Colin he knew was "very positive and upbeat" and had been planning to be a pilot once again.

Mr Williams was surprised and amazed at the wreck's discovery, which he said brought a tale of triumph over adversity into the present.

"It was such a fantastic story that he had, under those circumstances, managed to wrestle his way free of the cockpit and live on. It was testament to his strength of spirit," he said.

Recovery of the wreck will start later this month. Both the Australian War Memorial in Canberra and Darwin's Australian Aviation Heritage Centre are interested in displaying it.

Michael Wells, heritage director at the NT Department of Tourism and Culture, said it could teach people about the "ferocious" 18-month Japanese attack, and be "a great tribute to a very brave man and in turn a tribute to all the brave people that helped to defend Australia during that time".