Malaysia Airlines Flight 370 (MH370 / MAS370) was an international passenger flight operated by Malaysia Airlines that disappeared from radar on 8 March 2014 while flying from Kuala Lumpur International Airport in Malaysia to its planned destination, Beijing Capital International Airport in China, with the 227 passengers and 12 crew members on board. The cause of its disappearance has not been determined. It is widely regarded as the greatest mystery in aviation history.
The crew of the Boeing 777, registered as 9M-MRO, last communicated with air traffic control (ATC) around 38 minutes after takeoff when the flight was over the South China Sea. The aircraft was lost from ATC's secondary surveillance radar screens minutes later, but was tracked by the Malaysian military's primary radar system for another hour, deviating westward from its planned flight path. It left radar range 200 nautical miles (370 km; 230 mi) west-northwest of Penang Island in northwestern Peninsular Malaysia.
With all 227 passengers and 12 crew aboard presumed dead, the disappearance of Flight 370 was the deadliest incident involving a Boeing 777, the deadliest of 2014, and the deadliest in Malaysia Airlines' history until it was surpassed in all three regards by Malaysia Airlines Flight 17 on 17 July 2014. Relying mostly on the analysis of data from the Inmarsat satellite with which the aircraft last communicated, the Australian Transport Safety Bureau (ATSB) initially proposed that a hypoxia event was the most likely cause given the available evidence, although no consensus has been reached among investigators concerning this theory. At various stages of the investigation, possible hijacking scenarios were considered, including crew involvement, and suspicion of the aircraft's cargo manifest; many disappearance theories regarding the flight have also been reported by the media.
The search for the missing aircraft became the most expensive search in the history of aviation. It focused initially on the South China Sea and Andaman Sea, before a novel analysis of the aircraft's automated communications with an Inmarsat satellite indicated that the aircraft had travelled far southward over the southern Indian Ocean. Several pieces of debris washed ashore in the western Indian Ocean during 2015 and 2016; many of these were confirmed to have originated from Flight 370. After a three-year search across 120,000 km2 (46,000 sq mi) of ocean failed to locate the aircraft, the Joint Agency Coordination Centre heading the operation suspended its activities in January 2017. A second search launched in January 2018 by private contractor Ocean Infinity also ended without success after six months. The Malaysian Ministry of Transport's final report from July 2018 was inconclusive. It highlighted Malaysian ATC's fruitless attempts to communicate with the aircraft shortly after its disappearance.
In the absence of a definitive cause of disappearance, air transport industry safety recommendations and regulations citing Flight 370 have been implemented to prevent a repetition of the circumstances associated with the loss. These include increased battery life on underwater locator beacons, lengthening of recording times on flight data recorders and cockpit voice recorders, and new standards for aircraft position reporting over open ocean.
Flight 370 last made voice contact with ATC at 01:19 MYT, 8 March (17:19 UTC, 7 March) when it was over the South China Sea, less than an hour after takeoff. It disappeared from ATC radar screens at 01:22 MYT, but was still tracked on military radar as it turned sharply away from its original northeastern course to head west and cross the Malay Peninsula, continuing that course until leaving the range of the military radar at 02:22 while over the Andaman Sea, 200 nautical miles (370 km; 230 mi) northwest of Penang Island, in northwestern Malaysia.
The multinational search effort for the aircraft, which was to become the most expensive aviation search in history, began in the Gulf of Thailand and the South China Sea, where the aircraft's signal was last detected on secondary surveillance radar, and was soon extended to the Strait of Malacca and Andaman Sea. Analysis of satellite communications between the aircraft and Inmarsat's satellite communications network concluded that the flight continued until at least 08:19 (nearly an hour after Malaysia Airlines publicly announced the aircraft's loss) and flew south into the southern Indian Ocean, although the precise location cannot be determined. Australia assumed charge of the search on 17 March, when the search effort began to emphasise the southern Indian Ocean. On 24 March, the Malaysian government noted that the final location determined by the satellite communication was far from any possible landing sites, and concluded, "Flight MH370 ended in the southern Indian Ocean."
From October 2016 to January 2017, a comprehensive survey of 120,000 km2 (46,000 mi2) of sea floor about 1,800 km (1,100 mi; 970 nmi) southwest of Perth, Western Australia, yielded no evidence of the aircraft. Several pieces of marine debris found on the coast of Africa and on Indian Ocean islands off the coast of Africa—the first of which was discovered on 29 July 2015 on Réunion—have been confirmed as pieces of Flight 370. The bulk of the aircraft has not been located, prompting many theories about its disappearance.
In January 2018, a search by private US marine exploration company Ocean Infinity began in the search zone around 35.6°S 92.8°E / -35.6; 92.8 (CSIRO crash area), the most likely crash site according to the drift study published in 2017. In a previous search attempt, Malaysia had established a Joint Investigation Team (JIT) to investigate the incident, working with foreign aviation authorities and experts. Malaysia released a final report concerning Flight 370 on 17 October 2017. Neither the crew nor the aircraft's communication systems relayed a distress signal, indications of bad weather, or technical problems before the aircraft vanished.
Two Iranian passengers travelling on stolen passports were investigated but eliminated as suspects. Malaysian police identified the captain as the prime suspect if human intervention was the cause of the disappearance, after clearing all others on the flight of suspicion over possible motives. Power was lost to the aircraft's satellite data unit (SDU) at some point between 01:07 and 02:03; the SDU logged onto Inmarsat's satellite communication network at 02:25, which was three minutes after the aircraft had left the range of radar. Based on analysis of the satellite communications, the aircraft was postulated to have turned south after passing north of Sumatra and then to have flown for six hours with little deviation in its track, ending when its fuel was exhausted.
With the loss of all 239 lives on board, Flight 370 is the second-deadliest incident involving a Boeing 777 and the second-deadliest incident of Malaysia Airlines' history, second to Flight 17 in both categories. Malaysia Airlines was struggling financially, a problem that was exacerbated by a decrease of ticket sales after the disappearance of Flight 370 and the downing of Flight 17; the airline was renationalised by the end of 2014. The Malaysian government received significant criticism, especially from China, for failing to disclose information promptly during the early weeks of the search. Flight 370's disappearance brought to public attention the limits of aircraft tracking and flight recorders, including the limited battery life of underwater locator beacons (an issue that had been raised about four years earlier following the loss of Air France Flight 447 but had never been resolved). In response to Flight 370's disappearance, the International Civil Aviation Organization adopted new standards for aircraft position reporting over open ocean, extended recording time for cockpit voice recorders, and, starting from 2020, new aircraft designs have been required to have a means of recovering the flight recorders, or the information they contain, before they sink into the water.