In 1937, Earhart and Noonan set out (for the second time) to fly around the world in a twin-engine Lockheed Electra.

They left Miami in the United States on 1 June and, after scheduled stops in South America, Africa, India and South East Asia, arrived in Lae on 29 June. At Lae they had completed 35,000 kilometres pf their journey and had 11,000 kilometres across the Pacific to go.

Then the aircraft vanished somewhere over the central Pacific before a refuelling stop planned for Howland Island, an uninhibited coral outcrop 2,700 kilometres south-east of Hawaii.

We know that the Lockheed Electra was heavily loaded from Lae on its way to Howland Island, a journey supposed to last about 18 hours. The USA coastguard ship Itasca, patrolling off Howland Island at the time, was to provide communications support to Earhart as she neared the island.

One of her last radio messages, which she repeated several times, was that she could not see the island and that fuel was running low.

From this slender fragment of information have developed much speculation and many interesting conspiracy theories from credible – and some incredible – sources.

The Nikumaroro Island theory is that Earhart and Noonan died on this uninhabited island as castaways.

The discovery of 12 bones said to match those of Earhart and Noonan have undergone various scientific tests without any conclusion being reached.

The theory suggests that the other bones were eaten by the coconut crabs endemic to the island. You can read more about this theory here and draw your own conclusions.

Papua New Guinea has two provinces which claim to have found the remains of Earhart. In 2011, the discovery on Buka Island of a plane believed to be Earhart's was reported in the UK Daily Mail. The locals firmly believed their discovery would yield a treasure worth millions of dollars.

At the time a researcher from the International Group for Historic Aircraft Recovery said “there are strong indications that the aircraft is a Lockheed Model 10 Electra [and] the crash site is in direct alignment with Earhart’s flight path out of Lae, past north of Buka Island in a straight northeast direction to Howland."

This further confused the Earhart story. Did the aircraft crash this early in the flight or was it closer to Howland Island? Did those last distress calls come from Nikumaroro, Bougainville or even West New Britain, where people from Kandrian are developing track to the possible crash site and building a local museum in remembrance of Earhart?

Senior PNG journalist Malum Nalum wrote on his blog about the Kandrian discovery: ''Suddenly they came upon a wrecked aircraft - a twin engine, twin tailed plane much like that of Earhart”. But this was 3,200 kilometers short of Howland Island. More speculation and, as PNG people would say, even a 'cargo cult' trend developing out of the Earhart mystery

There are stories of an Earhart crash site in the Solomon Islands but the radio direction indicator bearing shows the Solomons are far south-east of the route Earhart took so it can be safely dismissed.

The last calls from Earhart seem to confirm she had travelled the calculated distance and was near Howland Island. Her distress calls were recorded although the coastguard ship Itasca was unable to locate the aircraft.

The world was building towards war in 1937 and there were military bases established across the Pacific. This had led to another theory that Earhart fell victim of pre-war tensions.

Earhart's disappearance was tragedy but her legacy lives on to this day. She inspired and encouraged the inclusion of women in aviation and other pursuits.

I regard as a hero, a fearless woman who was a pioneer of the aviation history.