AKIPRESS.COM - Malaysia Airlines Flight 370 vanished in March 2014, and for 18 months, no trace of it was found.

The location of the missing passenger jet officially remains a mystery, but the recent discovery of a missing piece of a Boeing 777 on an island off the coast of Madagascar has given searchers renewed hope that they might learn what happened to the plane's 239 passengers and crew members, all of whom are presumed dead, reports Los Angeles Times.

Although the July 29 discovery is being treated as a "significant development" by authorities, experts do not believe the Boeing 777 piece alone will lead search crews to the rest of the plane.

Nearly a year and a half in, the reason for the plane's disappearance remains a source of a lot of speculation and few facts.

Here's a synopsis of one of the most mysterious plane disappearances in aviation history.

Where the plane was headed

On the morning of March 8, 2014, the Beijing-bound plane departed Kuala Lumpur around 12.20 am with 227 passengers and 12 crew members on board. The plane's planned flight path would have taken it north over the Gulf of Thailand and Vietnam, with an arrival in Beijing around 6.30 am.

Who was on board

More than 150 passengers were from China, 38 from Malaysia and three from the United States. Other passengers were from Indonesia, Australia, France, New Zealand, Ukraine, Canada, Russia, Taiwan, Italy, the Netherlands and Austria, officials said. The pilot, Capt. Zaharie Ahmad Shah, 53, and copilot, Fariq Abdul Hamid, 27, were both Malaysian. Shah had 18,000 hours of flying time, and Hamid had 2,700.

One of the Americans on board was Philip Wood, a 50-year-old IBM executive. Another passenger was martial arts expert Ju Kun, who had recently joined the production of the Netflix series "Marco Polo", which was filming in Malaysia.

Last contact with the plane

Around 1 am, the plane let off a final ACARS transmission signal, which allows computers aboard the plane to communicate with control towers on the ground. According to officials, the last communication MH370 had with air traffic control came around 1.20 am, when one of the pilots said, "Good night Malaysia three seven zero."

Shortly after that, officials with the Civil Aviation Administration of Vietnam said, the plane failed to check in as scheduled with air traffic controllers in Ho Chi Minh City, Vietnam, and all computers that could track its location were deactivated.

How the flight path changed

Based on military radar, it is believed the plane changed course immediately after the communications systems were deactivated. It banked west from its northern path and headed back toward Malaysia and out over the Indian Ocean. U.S. investigators suspect MH370 remained in the air for up to four hours before crashing into the Indian Ocean.

Some theories on what might have occurred

Theories included a possible electrical failure or a fire in the cockpit. Terrorism was also considered, especially because two Iranian men had used stolen passports to board the plane, but it was later ruled out.

Was it pilot error? That remains a mystery. Investigators looked into Shah and Hamid, but because the black boxes that hold flight data recordings have not been discovered, investigators don't have a definitive answer.

In March, a report conducted by Malaysia's Ministry of Transport found that a battery on one of two underwater beacons attached to the plane's black box had expired more than a year before the aircraft vanished. That finding suggests that searchers listening for "pings" from the beacons on the flight data recorder and the cockpit voice recorder never even had a chance of detecting a signal from one of the devices.

The initial search

Search teams began by looking for the plane in the Indian Ocean about 1,600 miles off the coast of Perth, Australia. Pings thought to be from the plane's black box recorders were being picked up in the area, and a fleet of ships and aircraft were dispatched. Satellites located debris and some oil slicks were seen in the water, though nothing was recovered. After about 10 days searching the area, radar estimates were recalibrated and the search was moved about 700 miles northeast, where it remains.

In January, the plane's disappearance was ruled an accident. "At this juncture, there is no evidence to substantiate any speculations as to the cause," Azharuddin Abdul Rahman, director general of the civil aviation department, said at the time.

Status of the search

Officials from China, Australia and Malaysia have scoured nearly 1.8 million square miles of the Indian Ocean. China noted in January that it has tapped "massive resources" to search for the aircraft, including 21 satellites, 19 vessels, 13 aircraft and more than 2,500 personnel.

Underwater vehicles equipped with sonar have been searching a zone of more than 23,000 square miles off the western coast of Australia, an effort that is about 75% complete and is expected to be finished by late spring.

In May, search teams scouring the Indian Ocean off Australia’s west coast found a shipwreck. Vessels with towing sonar sensors discovered what appeared to be man-made objects on the seafloor, more than 12,000 feet deep. Further investigation with an underwater camera revealed an anchor and what authorities said appeared to be lumps of coal. The largest object discovered was described as box-shaped and about 18 feet long.

Officials said at the time they did not believe the wreck was linked to the missing jetliner, but they chose to examine the site anyway.

“This wreck is previously uncharted and the imagery will be provided to expert marine archaeologists for possible identification,” the Joint Agency Coordination Center said.

The missing piece?

On July 29, a piece of an airplane wing was discovered on Reunion Island, which belongs to France and sits off the coast of Madagascar in the Indian Ocean.

Days later, a Malaysian transport official said the piece – called a flaperon – was from a Boeing 777.

Abdul Aziz Kaprawi, the country's deputy transport minister, told reporters he believed the item could provide "conclusive proof that Flight MH370 crashed into the Indian Ocean," and said he believed officials were "close" to solving the mystery of the jetliner's disappearance.

The item was discovered within the 1,100-mile search area investigators have been operating in since 2014, but experts believe the plane probably went down far from Reunion Island. The length of time since the plane disappeared and the onset of winter in the search area will keep search efforts at a crawling pace, they say.

What else the wing piece could show

The piece has yet to be analyzed, but close-up pictures showing damage suggest it broke off the aircraft during a high-speed dive, a prominent aviation accident analyst said.

That would validate one of the main theories about what happened to the plane: "that when the aircraft ran out of fuel it made an almost straight spiral down," said David Soucie, a former accident investigator for the Federal Aviation Administration.

If that's the case, it would reduce the projected search area for other parts of the plane by about 8 miles in each direction, he said.

What has happened to the passengers' families?

Malaysia's official declaration that the plane's disappearance was an accident should clear the way for the compensation process to proceed for families of the 239 people who were on board. The passengers and crew members are officially presumed dead.

"Without in any way intending to diminish the feelings of the families, it is hoped that this declaration will enable the families to obtain the assistance they need, in particular through the compensation process," Rahman of the civil aviation department said at the time.

Sarah Bajc, the partner of passenger Wood, has joined with others in hiring a private investigation firm with about $100,000 they have raised. Bajc, 48, was in Beijing waiting for Wood when the plane disappeared.

"I won't give up hope until there's proof otherwise," Bajc told The Times last year.

Despite the discovery on Reunion Island, relatives of the missing passengers said they will remain skeptical about their loved ones' fates until authorities recover the entire plane.

"Before they find actual bodies, I won't believe anything," Cheng Liping, whose husband was on the plane, posted to the Chinese social media site Weibo the day the piece was discovered. "A wing doesn't mean much."