Dec 3 - The disappearance nearly 12 years ago of Malaysia Airlines flight MH370 with 239 people on board remains one of the world's greatest aviation mysteries.

The Boeing 777 went missing on its way from Kuala Lumpur to Beijing on March 8, 2014. More than 150 Chinese passengers and 50 Malaysians were on the flight, as well as citizens of France, Australia, Indonesia, India, the United States, Ukraine and Canada, among others.

Satellite data analysis showed the plane likely crashed somewhere in the southern Indian Ocean, off the coast of western Australia. However, two major searches failed to come up with any significant findings.

A new search for the missing aircraft will commence on December 30, 2025.

WHAT IS KNOWN?

The last transmission from the plane was about 40 minutes after it took off from Kuala Lumpur for Beijing. Captain Zaharie Ahmad Shah signed off with "Good night, Malaysian three seven zero", as the plane entered Vietnamese airspace. 

Shortly thereafter, its transponder was turned off, which meant it could not be easily tracked.

Military radar showed the plane left its flight path to fly back over northern Malaysia and Penang Island, and then out into the Andaman Sea towards the tip of the Indonesian island of Sumatra. It then turned south and all contact was lost.

UNDERWATER SEARCHES

Malaysia, Australia and China launched an underwater search in a 120,000 sq km (46,332 sq miles) area in the southern Indian Ocean, based on data of automatic connections between an Inmarsat satellite and the plane.

The search, which cost about A$200 million ($131.54 million), was called off after two years in January 2017, with no traces of the plane found.

In 2018, Malaysia accepted a "no-cure, no-fee" offer from U.S. exploration firm Ocean Infinity for a three-month search, meaning the company would only get paid if it found the plane.