The World’s Strangest Unsolved Airplane Mysteries

Plane debris that could possibly be linked to missing flight MH370 has been discovered washed up on the beach of a remote island in the Indian Ocean, officials revealed on Wednesday. The component found is believed to be the flaperon from a Boeing 777, the same type of plane that disappeared over the southern Indian Ocean in March 2014, with 239 people onboard.

An office building is illuminated with LED lights displaying “Pray for MH370” next to Malaysia’s landmark Petronas Twin Towers in Kuala Lumpur, Malaysia, on March 19, 2014. (AP Photo/Lai Seng Sin, File)

Malaysia Airlines Flight 370 is the only Boeing 777 currently unaccounted for, and experts have taken the part away for further analysis in an attempt to determine its origin.

This is the first major development in the flight’s puzzling disappearance over a year ago in an event that has become one of the biggest unsolved aviation mysteries in history.

However, this is not the first time a plane has disappeared or crashed under mysterious circumstances. Here are some of the other unexplained aviation disasters that have taken place in the last century.

The shadow of a Royal New Zealand Air Force P3 Orion is seen on low-level clouds while the aircraft searches for missing Malaysia Airlines Flight MH370 in the southern Indian Ocean, near the coast of Western Australia. (AP Photo/Rob Griffith, File)

1. Aer Lingus Flight 712

On March 24, 1968, Aer Lingus Flight 712 from Cork in Ireland to London’s Heathrow Airport crashed into the sea, killing all 61 onboard.

But when investigators looked into the crash, they could find no explanation for what brought the plane down. In the years following the crash, several witnesses came forward to claim that the plane had been shot down by an experimental British missile — a claim that was strongly refuted by the British government.

Related: How to Combat the Fear of Flying After Malaysia Airlines Crash

2. B47 Stratojet Bomber
In March 1956, a Boeing B47 Stratojet long-range bomber carrying three U.S. Air Force personnel vanished over the Mediterranean Sea while en route from MacDill Air Force Base in Florida to Ben Guerir Air Force Base in Morocco. The plane disappeared without a trace. Frighteningly, the bomber was carrying two nuclear warheads, which were never recovered.

3. Helios Airways Flight 522
On Aug. 14, 2005, Greek air traffic controllers lost contact with Helios Airways Flight 522 as it headed toward Athens airport to begin its descent after a short trip from Cyprus. Strangely, the plane stayed within its set holding pattern around the airport for over an hour. When fighter jets were scrambled to intercept the flight, they saw the pilot slumped over the controls. The plane descended rapidly around 30 minutes later, crashing into a hillside outside the city and killing all 121 souls onboard. An investigation into the crash determined that there may have been a gradual cabin pressure loss that had likely incapacitated the crew.

Related: From Costa Concordia to the Missing Malaysia Airlines Plane, Tragedy Tourism Is on the Rise

4. Amelia Earhart’s Lockheed Electra
One of the most famous aviation mysteries in history occurred in 1937 when the Lockheed Electra plane, piloted by pioneer aviator Amelia Earhart, vanished over the Pacific Ocean during her attempt to circumnavigate the globe. No wreckage was ever found, and the plane’s disappearance has been the focus of intense conspiracy theories ever since. There have been stories of her being shot down by the Japanese or being a spy. Some have speculated that she faked her own death, and a very small contingent is convinced she was abducted by aliens.

Amelia Earhart’s plane rising into the air after a 4,000-foot run at the start of the flight from Oakland, California, on March 17, 1937. (AP Photo)

5. Flight 19
Flight 19 was the name given to a U.S. Air Force training exercise that took place on Dec. 5, 1945, involving an Avenger Torpedo Bomber. The plane disappeared over the Bermuda Triangle with 14 airmen on board. The Air Force then sent a Mariner flying boat with 13 men onboard to attempt to find the missing aircraft. That plane also went missing. Neither of the planes, nor the 27 crew members in total, were ever seen again, and investigators could never determine the cause of either flight’s disappearance.

6. Egypt Air Flight 990
Flight 990 was a scheduled flight from Los Angeles to Cairo with a stopover in New York. But on Oct. 31, 1999, the Boeing 747 plane mysteriously crashed into the Atlantic Ocean about 100 miles south of Nantucket, killing all 217 people onboard, including 14 crew members. While investigators never discovered the specific cause of the crash, the FBI believed that the evidence suggested the crash was deliberate rather than accidental. Egyptian and American authorities never agreed on the cause of the crash, with the Egyptians concluding it was due to mechanical malfunction and the Americans stating it was the responsibility of the relief first officer.

Egypt Air Captain Hatem Rushdi, who piloted Egypt Air Flight 990 from Los Angeles to New York on Oct. 31, 1999, is seen in this undated picture. He was a passenger when the plane went down after taking off from New York en route to Cairo. (AP Photo)

7. Pan Am Flight 7
Pan Am Flight 7 was once considered to be one of the most exclusive and luxurious “around the world trips” available. But in 1957, during a leg from Los Angeles to Hawaii, the Boeing Stratocruiser vanished into thin air. Rescue crews hunted for five days before finding the plane floating in the ocean, hundreds of miles off course, with very little actual damage to the plane. Autopsies on the passengers found that they had been poisoned by carbon monoxide emissions, but no reason for the poisoning was ever found. Many speculated that it was possibly an act of insurance fraud.

Related: Learning to Survive a Plane Crash

8. Air France Flight 447
On the morning of June 1, 2009, Air France Flight 447, traveling from Rio De Janeiro to Paris, went missing with 216 passengers and 12 crew members onboard. The Airbus A330 had flown through a thunderstorm, but no distress signal was sent. For several days there was no trace of the plane, and it took over two years to recover the black boxes from the ocean floor. Analysis of the boxes found that a combination of equipment malfunction and human error resulted in the crash.

Workers unload debris from crashed Air France Flight 447 from the Brazilian Navy’s Constitution Frigate in the port of Recife, northeast of Brazil, on June 14, 2009. A burst of last-minute automatic messages sent by the plane includes one about a problem with a rudder safety device, but that does not explain what sent the jet plunging into the Atlantic Ocean, an aviation expert said. (AP Photo/Eraldo Peres)