The Pacific is the largest single feature on the planet. In 1928 nobody had flown across it, and the reason was arithmetic: the distances between usable landfalls were longer than any aircraft could reliably manage, and if you missed the island you were aiming at, there was no second island.

Charles Kingsford Smith did it in a second-hand Dutch airliner that had already been written off once in the Arctic.

A salvaged aeroplane and other people’s money

IL Southern Cross started life as the Detroiter, flown on a Detroit News Arctic expedition and crashed in Alaska in 1926. Sir Hubert Wilkins salvaged the airframe and sold it in San Francisco to Kingsford Smith and Ulm — without engines, and without instruments.

The three Wright Whirlwinds were paid for by the Melbourne businessman Sidney Myer. The airframe itself ended up owned by a Californian oilman, G. Allan Hancock, who bought it and lent it back to them. The whole enterprise was assembled out of goodwill, borrowed money and a wreck.

Navigating to a dot

The hard part was never the flying. It was finding Hawaii, and then finding Fiji, using a sextant, a drift sight and dead reckoning, from an aircraft that vibrated continuously and had no autopilot.

Harry Lyon, the American navigator, had prepared by taking star sights from a moving car to simulate an unstable platform. This turned out to have complications.

They left Oakland on 31 May 1928 and reached Wheeler Field in Hawaii after 27 hours and 25 minutes. The second leg, from Kauai to Suva, was the one that mattered: 5,077 kilometres, thirty-four and a half hours, through an equatorial lightning storm, to an island group no aircraft had ever landed on before.

The final leg from Suva to Brisbane brought the worst weather of the trip — Lyon called it exactly that — with a leaking windscreen soaking the pilots for hours. They crossed the Australian coast near Ballina and landed at Eagle Farm on 9 June, in front of a crowd counted somewhere between fifteen and twenty-five thousand.

What came after

He did not stop. Later that year he made the first non-stop crossing of Australia and then the first flight across the Tasman Sea, Sydney to Christchurch, in 14 hours 25 minutes. In 1930 he flew the Atlantic east to west, from Ireland to Newfoundland, which meant the Southern Cross had now been round the world.

On 8 November 1935, flying a Lockheed Altair called Lady Southern Cross with his co-pilot Tommy Pethybridge, he disappeared over the Andaman Sea on a night leg from Allahabad to Singapore. Another aviator reported seeing the aircraft low over the water in a storm. No bodies were ever found. Eighteen months later an undercarriage leg with its tyre still inflated washed ashore in Burma, and Lockheed confirmed it was his.

He was 38.

Australian newsreel of the arrival at Eagle Farm and Mascot:

A recording of Kingsford Smith and Ulm speaking, made in June 1928, days after they landed:

And the aircraft itself, still at Brisbane Airport:

Sources: Australian Dictionary of Biography; State Library of New South Wales; State Library of Queensland; National Museum of Australia; Maine Historical Society on Harry Lyon.