Captain Selwyn was a central figure in the $500,000 Mr Brown bomb hoax against Qantas.

In May 1971, two men, one calling himself Mr Brown, successfully extorted $500,000 from Qantas when they telephoned the Commonwealth Police in Sydney saying there was an altitude-linked bomb on board Qantas flight 755 to Hong Kong.

Captain Selwyn was the captain of the Boeing 707.

Police were told the bomb would explode if the plane, with 128 passengers on board, flew below 20,000 feet.

Mr Brown also said there was an identical bomb hidden in a locker at Mascot Airport.

This bomb was found, and army experts confirmed the altitude-sensitivity of the bomb and the potential danger to all aboard Captain Selwyn’s plane.

Captain Selwyn had been told of the hoax as the plane was near Longreach in Queensland.

He turned back to Sydney, started an in-flight search for the bomb, dismantling panels with a metal nail file, and then circled Sydney for hours, burning up fuel before being allowed to land.

One of the army bomb experts later described Captain Selwyn as the calmest man in a crisis he had ever met.

Mr Brown, whose real name was Peter Macari, telephoned after he had been paid the $500,000 and said there was no bomb aboard Captain Selwyn’s plane.

Macari was arrested and deported to Britain after serving nine years of a 15-year term.

In 1986, a TV film starring Chris Haywood and Vincent Ball was made about the hoax.

Captain Selwyn was born at Rose Bay, Sydney in 1922.

He joined the RAAF in 1942 and after training in NSW and Canada, served with the RAF’s No.36 squadron Coastal Command, flying Wellington bombers on anti-submarine patrols in North Africa, Italy and the Outer Hebrides.

The only time he saw a U-boat was when one surrendered a few days after the war’s end.

After the war, Captain Selwyn flew newspaper delivery planes for the Sydney Morning Herald, and then worked for Cathay Pacific and McRobertson Miller in WA before joining Qantas.

He is survived by his wife Christina, son Michael, grand-daughters Ann-Michel, Heather, Amy, Jennifer and great-grandsons Cameron and Darcy.