KUALA LUMPUR, July 30 -- Today saw arguably the most exciting development since Malaysia Airlines (MAS) Flight MH370 went missing nearly 18 months ago, with a 2.7m-long piece of debris discovered on Réunion Island in the Indian Ocean.

Aviation experts have since speculated that the debris is a “flaperon” marked “BB 670”, most probably from a Boeing 777, which has been encrusted with barnacles.

Malaysia has since sent a team to investigate, assisted by of Boeing, the BEA (Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile), the US National Transportation Safety Bureau and the Australian Transport Safety Bureau.

Here is what we know so far about the debris:

What is a flaperon?

A “flaperon” is a combination of a “flap” and “aileron”, which are control surfaces on an aircraft’s wings that allow pilots to control and adjust a plane’s movement by deflecting air stream passing over them.

Flaps increase drag for an aircraft to keep it flying at a slower speed and increase the angle of descent during landing, so takeoffs and landing distances can be shorter.

Ailerons (French for “little wings”) are used to control the “roll” or an aircraft to the left or right.

Flaps, ailerons and flaperons are mounted on the trailing edges of an aircraft’s wings.

When was the debris found?

The debris was found this morning (Malaysian time) when people were cleaning a beach in Saint-André, on the east coast of Réunion.

Since it was covered in barnacles, it is believed to have been long submerged in water.

Eric Chesneau, an officer in the air transport police of Réunion, said that it was “more than likely plane debris” that had washed up, but further inspection was needed.

Where in the world is Réunion Island?

Réunion Island, or La Réunion in French, is part of France’s overseas department situated in the Indian Ocean near the African continent. Despite that, it is considered part of the euro zone.

Réunion is situated east of Madagascar in Southeast Africa, and lies 175 km southwest of Mauritius, the nearest island there.

The island is around 4,200km or about 2,268 nautical miles away from the current search area of MH370.

 Who said the flaperon is from MH370?

French aviation expert Xavier Tytelman was the first to point out the similarities between the debris and a flaperon.

A mechanic from Réunion-based airline Air Austral also claimed to have studied the debris with French military officials and concluded that he is “99.9 per cent certain” that it originated from a Boeing 777.

However, French aviation security expert and criminologist Christophe Naudin suggested that the debris likely belongs to a light twin-engine plane, and might be linked to a previous crash involving a Piper plane in 2006.

How do they know if debris is from MH370?

They do not know for sure yet, since most of the speculation came only from observing the photos of the debris circulated online.

The US National Transport Safety Bureau investigator Greg Feith has said that manufacturers put data tags on every part that goes on an aircraft.

Some commenters have claimed that the “BB 670” refers to 670, the zone of parts linked to the jetliner’s right wing, according to Boeing’s Aircraft Maintenance Manual, but does not match a Boeing 777.

Naudin also claimed the string “BB 670” found on the wreckage is nonsensical as it did not match any aviation registration.

Despite that, Malaysian Deputy Transport Minister Datuk Abdul Aziz Kaprawi has insisted that it is “almost certain” that the flaperon is from a Boeing 777 aircraft, quoting Malaysia’s chief investigator.

Observers has since pointed out that there has only been 13 incidents involving a Boeing 777, and only one remotely near to Réunion: MH370.

There've only been 13 incidents involving Boeing 777s, and only one reported anywhere possibly near Reunion: #MH370 pic.twitter.com/emP6jl1nOi

Why did the debris end up there?

The Australian government has since said that the discovery, should it prove true, is “consistent” with analysis and modeling of the missing plane’s trajectory.

University of Western Australia oceanographer Professor Charitha Pattiaratchi also has produced a drift model made last year of possible areas debris from the plane may float to after it was determined that MH370 had probably crashed somewhere in the southern Indian Ocean.

The model indicates that within 18 to 24 months of a crash, the debris could have reached the ocean to the east of Madagascar, close to Réunion. MH370 crashed nearly 17 months ago.

However, due to the time between the MH370’s disappearance last year and potential debris discovery, he said it would not be possible to pinpoint the spot where the plane might have gone down.

Possible drift of MH370 wreckage model by Prof Charitha Pattiaratchi, University of Western Australia. Picture courtesy of Prof Charitha Pattiaratchi, University of Western Australia>