Adventurer and MH370 sleuth Blaine Gibson has brought what he believes is the most significant piece of potential wreckage from the missing Malaysia Airlines plane to Australia for analysis.
The fragment, found by three locals on the east coast of Madagascar and passed on to Gibson, appears to have come from the interior of a Boeing 777 and exhibits signs of having been exposed to fire or a great heat.
"The top layer of paint has been singed, scorched black," Gibson told Channel 7 after touching down in Australia.
"(It's significant) because it appears to be from the interior of the plane but not the main cabin, perhaps the cargo hold, perhaps the avionics bay."
Gibson personally handed over the debris to Australian Transport Safety Bureau (ATSB) investigators in Canberra this morning.
If confirmed to have come from the plane, it will be the first evidence that a fire - possibly an electrical one - brought down MH370 rather than the actions of a suicidal pilot.
Gibson said it was also possible the burn marks could have come from the force of impact.
"The sea is slowly giving up her secrets," he told Airline Ratings.com.
"I believe these pieces are extremely important."
Gibson has found 13 of the 27 pieces of suspected and confirmed MH370 debris that have been found to date during beachcombing expeditions in Mozambique, Madagascar and the region.
Of the 13, roughly half have been confirmed by Australian investigators as "highly likely" to have come from the missing plane.
Previously, Gibson has entrusted his finds to local authorities but he believes the latest fragments - including the one with burn marks and a suspected frame from a monitor attached to the back of a plane seat - are too important to leave in the hands of others.
"Malaysia is yet to pick up five pieces I found there three months ago," Gibson told Airline Ratings.
The ATSB confirmed that it had received the debris but said it planned to consult Malaysia before taking any action.
"Yes, the ATSB has today received debris from Gibson and are seeking advice from Malaysian authorities regarding how they would like to proceed," a spokesman told news.com.au.
"Note that the Malaysian Government is responsible for the investigation and therefore is responsible for the analysis of all possible MH370 debris."
Aviation specialist Geoffrey Thomas said if the latest piece was confirmed to have come from the avionics bay - where an aircraft's electronic systems are held - the implications were enormous.
"If it was proven this was from the avionics bay, it was a flash fire, yes, it changes everything," Mr Thomas told Channel 7 in Perth.
"It talks to the issue of why did two electronics systems shut down, apparently without any reason."
Speculation of a fire on board was rife in the days and weeks after the plane's disappearance on March 8, 2014, en route from Kuala Lumpur to Beijing with 239 people on board.
It increased after Malaysian authorities revealed the plane had been transporting a large amount of potentially flammable lithium batteries in its cargo.
The possibility of a botched remote hack of the plane's electronic and engineering bay (known as the E/E Bay) has also been discussed. Soon after the plane vanished, it was revealed that the bay could have been physically accessed via an unsecured hatch by a passenger or crew member with specialist knowledge.
Aviation writer Ben Sandilands, who has doggedly reported on developments, big and small, since the plane's disappearance, called the discovery a "highly significant find".
"(The debris found so far) all bear witness to a violent and sudden end to the flight, and underscore the indications from satellite data that it descended at high speed to the surface of the ocean," he wrote in an article overnight.
"The destructive force of that impact may have also reduced or eliminated the amount of larger and longer term floating objects that it could have produced.
"This looks like a highly significant find. But decoding it, and seeing how it fits in other clues as to what caused this disaster may take more time than the attention spans of the proponents of various fiercely advocated solutions to the mystery."