Malaysia Airlines Flight 370

Malaysia Airlines Flight 370

The missing aircraft, 9M-MRO, pictured in 2011
Incident
Date	8 March 2014
Summary	Missing
Site	Unknown
Aircraft
Aircraft type	Boeing 777-2H6ER
Operator	Malaysia Airlines
Registration	9M-MRO
Flight origin	Kuala Lumpur International Airport
Destination	Beijing Capital International Airport
Passengers	227
Crew	12

Malaysia Airlines Flight 370 (MH370/MAS370) was a scheduled international passenger flight from Kuala Lumpur to Beijing that lost contact with air traffic control on 8 March 2014 at 01:20 MYT, less than an hour after takeoff. At 07:24, Malaysia Airlines (MAS) reported the flight missing. The aircraft, a Boeing 777-200ER, was carrying 12 Malaysian crew members and 227 passengers from 14 nations. There has been no confirmation of any flight debris and no crash site has been found.

A multinational search and rescue effort, later reported as the largest in history, began in the Gulf of Thailand and the South China Sea. Within a few days, the search was extended to the Strait of Malacca and Andaman Sea. On 15 March, based on military radar data and radio "pings" between the aircraft and an Inmarsat satellite, investigators concluded that the aircraft had diverted from its intended course and headed west across the Malay Peninsula, then continued on a northern or southern track for around seven hours. The search in the South China Sea was abandoned. Three days later, the Australian Maritime Safety Authority began searching the southern part of the Indian Ocean.

On 24 March, the Malaysian government confirmed independent analyses by the British Air Accidents Investigation Branch (AAIB) and Inmarsat, and announced that search efforts would be concentrated on the Australian-led area. In the first two weeks of April, aircraft and ships deployed equipment to listen for signals from the underwater locator beacons attached to the aircraft's "black box" flight recorders. Four unconfirmed signals were detected between 6 and 8 April but after that time the batteries of the beacons were believed to have become exhausted. The search continued in the area of the signals, using a robotic submarine.

Disappearance

Route: Kuala Lumpur – Beijing. Insert: initial search areas and known path through waypoints IGARI, VAMPI, and IGREX. Small red squares: radar contacts. Small circles: claimed spotting of debris.

The flight departed from Kuala Lumpur International Airport on 8 March 2014 at 00:41 local time (16:41 UTC, 7 March) and was scheduled to land at Beijing Capital International Airport at 06:30 local time (22:30 UTC, 7 March). It climbed to its assigned cruise altitude of 35,000 feet (11,000 m) and was travelling at 471 knots (872 km/h; 542 mph) true airspeed when it ceased all communications and the transponder signal was lost. The aircraft's last known position on 8 March at 01:21 local time (17:21 UTC, 7 March) was at the navigational waypoint IGARI in the Gulf of Thailand, at which the aircraft turned westwards, heading towards a waypoint called VAMPI in the Strait of Malacca, primary radar tracking suggests that the aircraft descended as low as 12,000 feet (3,700 m). From there, the aircraft flew towards a waypoint called GIVAL, arriving at 2:15 local time (18:15 UTC, 7 March), thereafter to the Southern Thailand Islands (Andaman Coast) of Phuket, and was last plotted heading northwest towards another waypoint called IGREX.

The crew was expected to contact air traffic control in Ho Chi Minh City as the aircraft passed into Vietnamese airspace, just north of the point where contact was lost. The captain of another aircraft attempted to reach the crew of Flight 370 "just after 1:30 am" using the International distress frequency to relay Vietnamese air traffic control's request for the crew to contact it; the captain said he was able to establish contact, and just heard "mumbling" and static.

Malaysia Airlines (MAS) issued a media statement at 07:24, one hour after the scheduled arrival of the flight at Beijing, stating that contact with the flight had been lost by Malaysian ATC at 02:40. MAS stated that the government had initiated search and rescue operations. It later emerged that Subang Air Traffic Control had lost contact with the aircraft at 01:22 and notified Malaysia Airlines at 02:40. Neither the crew nor the aircraft's onboard communication systems relayed a distress signal, indications of bad weather, or technical problems before the aircraft vanished from radar screens.

Timeline of disappearance

Elapsed (HH:MM)	Time		Event
	MYT	UTC
00:00	8 March	7 March	Take-off from KUL (Kuala Lumpur)
	00:41	16:41
00:20	01:01	17:01	Crew confirms altitude of 35,000 feet (11,000 m)
00:26	01:07	17:07	Last ACARS data transmission received; crew confirms altitude of 35,000 feet, a second time
00:38	01:19	17:19	Last Malaysian ATC voice contact
00:40	01:21	17:21	Last secondary radar (transponder) contact at 6°55′15″N 103°34′43″E
00:41	01:22	17:22	Transponder and ADS-B no longer operating.
00:49	01:30	17:30	Voice contact attempt by another aircraft, at request of Vietnam ATC; mumbling and radio static heard in reply
00:56	01:37	17:37	Missed expected half-hourly ACARS data transmission
01:34	02:15	18:15	Last primary radar contact by Malaysian military, 200 miles (320 km) NW of Penang, 6°49′38″N 97°43′15″E
01:41	02:22	18:22	1st of 6 roughly hourly Classic Aero pings (handshakes) since last ACARS transmission, via the Inmarsat-3 F1 satellite
05:49	06:30	22:30	Missed scheduled arrival at PEK (Beijing)
06:43	07:24	23:24	Malaysia Airlines pronounces flight missing in statement released to media
07:30	08:11	8 March	6th and last successful automated hourly handshake with Inmarsat-3 F1
		00:11
07:38	08:19	00:19	Unscheduled, unexplained partial handshake transmitted by aircraft
08:34	09:15	01:15	Scheduled hourly ping attempt by Inmarsat goes unanswered by aircraft

Satellite pings

On 11 March, New Scientist reported that, prior to the aircraft's disappearance, two Aircraft Communications Addressing and Reporting System (ACARS) reports had been automatically issued to engine manufacturer Rolls-Royce's monitoring centre in the United Kingdom; and The Wall Street Journal, citing sources in the US government, asserted that Rolls-Royce had received an aircraft health report every thirty minutes for five hours, implying that the aircraft had remained aloft for four hours after its transponder went offline.

The following day, Hishammuddin Hussein, the acting Minister of Transport, refuted the details of The Wall Street Journal report stating that the final engine transmission was received at 01:07 MYT, prior to the flight's disappearance from secondary radar. The WSJ later amended its report and stated simply that the belief of continued flight was "based on analysis of signals sent by the Boeing 777's satellite-communication link... the link operated in a kind of standby mode and sought to establish contact with a satellite or satellites. These transmissions did not include data..."

Inmarsat said that "routine, automated signals were registered" on its network, and that analysis of "keep-alive message[s]" that continued to be sent after air traffic control first lost contact could help pinpoint the aircraft's location, which led The Independent to comment on 14 March that the aircraft could not have met with a sudden catastrophic event, or all signals would have stopped simultaneously. There was a call for automated transponders after the attacks of 11 September 2001; however, no changes were made as aviation experts preferred flexible control, in case of malfunctions or electrical emergencies.

On 25 March, Hishammuddin revealed that Inmarsat had found evidence that the aircraft had attempted another handshake with the satellite at 00:19 UTC, eight minutes after the last hourly report. This "partial ping" initiated by the aircraft was unscheduled, not the result of any human interaction.

Assumed loss

Messages of hope and prayer for MH370 at a bookstore in Malaysia

On 24 March, Malaysian Prime Minister Najib Razak said,

Using a type of analysis never before used in an investigation of this sort... Inmarsat and the AAIB have concluded that MH370 flew along the southern corridor, and that its last position was in the middle of the Indian Ocean, west of Perth. This is a remote location, far from any possible landing sites. It is therefore with deep sadness and regret that I must inform you that, according to this new data, flight MH370 ended in the southern Indian Ocean.

Just before Najib spoke at 22:00 MYT, Malaysia Airlines announced that Flight 370 was assumed lost with no survivors. It notified most of the families in person or via telephone, and some received the following SMS:

Malaysia Airlines deeply regrets that we have to assume beyond any reasonable doubt that MH370 has been lost and that none of those on board survived. As you will hear in the next hour from Malaysia's Prime Minister, we must now accept all evidence suggests the plane went down in the Southern Indian Ocean.

On 29 March, the Government of Malaysia and the AAIB stated that, in accordance with the protocols detailed in International Civil Aviation Organization (ICAO) Annex 13 concerning aircraft accident investigation, they would set up an international team to investigate the loss of the flight. On 30 March, Australian Prime Minister Tony Abbott announced the appointment of retired Australian Air Chief Marshal Angus Houston to head the Joint Agency Coordination Centre (JACC) to co-ordinate the search effort and closely co-operate with Malaysia, the responsible state under international law.

If the official assumption of no survivors holds, Flight 370 would be the deadliest aviation incident in the history of Malaysia Airlines (surpassing the 1977 hijacking and crash of Malaysian Airline System Flight 653 that killed all 100 passengers and crew on board); and the deadliest to date involving a Boeing 777, surpassing Asiana Airlines Flight 214. It would also be the second-deadliest incident in the Indian Ocean, behind Iran Air Flight 655; the 17th-deadliest incident of all time; and the deadliest incident since the February 2003 crash of an Iranian military aircraft.

Search

Hypothesised routes

Search for aircraft. Pink circle: Range of aircraft based on fuel (5,300 kilometres (3,300 mi)). Ping corridors: possible locations (in red) of aircraft at last ping to Inmarsat and possible last location (lighter red) based on residual fuel. Search areas: 1) 8–20 March, 2) 20–27 March, 3) 28 March.

On 11 March, it was reported that military radar indicated the aircraft turned west away from the intended flight path and continued flying for 70 minutes before disappearing from Malaysian radar near Pulau Perak. It was also reported that it had been tracked flying at a lower altitude across Malaysia to the Malacca Strait, approximately 500 kilometres (310 mi) from its last contact with civilian radar. The next day, the Royal Malaysian Air Force chief denied the report. A few hours later however, the Vietnamese transport minister claimed that Malaysia had been informed on 8 March by Vietnamese air traffic control personnel, that they had "noticed the flight turned back west".

Although Bloomberg News said that analysis of the last satellite "ping" received suggested a last known location approximately 1,000 miles (1,600 km) west of Perth, Western Australia, the Malaysian Prime Minister Najib Razak said on 15 March that the last signal, received at 08:11 Malaysian time, might have originated from as far north as Kazakhstan. Najib explained that the signals could not be more precisely located than to one of two possible loci: a northern locus stretching approximately from the border of Kazakhstan and Turkmenistan to northern Thailand, or a southern locus stretching from Indonesia to the southern Indian Ocean. Many of the countries on a possible northerly flight route – China, Thailand, Kazakhstan, Pakistan, and India – denied the aircraft could have entered their country's airspace, because military radar would have detected it.

It was later confirmed that the last ACARS transmission showed nothing unusual and a normal routing all the way to Beijing, The New York Times reported "senior American officials" saying on 17 March that the scheduled flight path was pre-programmed to unspecified western coordinates through the flight management system before the ACARS stopped functioning, and a new waypoint "far off the path to Beijing" was added. Such a reprogramming would have resulted in a banked turn at a comfortable angle of around 20 degrees that would not have caused undue concern for passengers. The sudden cessation of all on-board communication led to speculation that the aircraft's disappearance may have been due to foul play.

Hypothesised locations

As the available data analyses of the flight were refined, the foci of search operations changed to different areas in several distinct phases.

First phase

A MH-60R Sea Hawk lands aboard USS Pinckney during a crew swap before returning to the search and rescue on 10 March 2014

An admiral of the Vietnamese navy reported that radar contact with the aircraft was last made over the Gulf of Thailand. Oil slicks detected off the coast of Vietnam on 8 and 9 March later tested negative for aviation fuel. Alleged discovery of debris about 140 km (87 mi) south-west of Phú Quốc Island near 80 km (50 mi) south of Thổ Chu Island on 9 March was also found to be not from an aircraft. Searches following a Chinese website's satellite images, taken on 9 March, showing three floating objects measuring up to 24 × 22 metres (79 × 72 ft) at 6.7°N 105.63°E / 6.7; 105.63 (Three floating objects, 9 March) also turned up blank; Vietnamese officials said the area had been "searched thoroughly".

The Royal Thai Navy shifted its focus in the search away from the Gulf of Thailand and the South China Sea at the request of its Malaysian counterpart, which was investigating the possibility that the aircraft had turned around and could have gone down in the Andaman Sea, near Thailand's border. The chief of the Royal Malaysian Air Force, Rodzali Daud, claimed that military recordings of radar signals did not exclude the possibility of the aircraft turning back on its flight path. The search radius was increased from the original 20 nautical miles (37 km; 23 mi) from its last known position, south of Thổ Chu Island, to 100 nautical miles (190 km; 120 mi), and the area being examined then extended to the Strait of Malacca along the west coast of the Malay Peninsula, with waters both to the east of Malaysia in the Gulf of Thailand, and in the Strait of Malacca along Malaysia's west coast, being searched.

On 12 March, authorities also began to search the Andaman Sea, northwest of the Strait of Malacca, and the Malaysian government requested help from India to search in the area.

Second phase

Chinese PLAAF Ilyushin Il-76 arriving at RAAF Base Pearce in Perth, Australia on 21 March 2014

On 13 March, White House Press Secretary Jay Carney said "an additional search area may be opened in the Indian Ocean based on some new information" and a senior official at The Pentagon told ABC News: "We have an indication the plane went down in the Indian Ocean." On 17 March, Australia agreed to lead the search in the southern locus from Sumatra to the southern Indian Ocean. The search would be coordinated by the Australian Maritime Safety Authority (AMSA), with an area of 600,000 km² (230,000 sq mi) between Australia and the Kerguelen Islands lying more than 3,000 kilometres (1,900 mi) Southwest of Perth, to be searched by ships and aircraft of Australia, New Zealand, and the United States. This area, which Australian PM Tony Abbott described as "as close to nowhere as it's possible to be", is renowned for its strong winds, inhospitable climate, hostile seas, and deep ocean floors. On 18 March, the search of the area began with a single Royal Australian Air Force P-3 Orion aircraft. On 19 March, the search capacity was ramped up to three aircraft and three merchant ships; the revised search area of 305,000 square kilometres (118,000 sq mi) was about 2,600 kilometres (1,600 mi) south-west of Perth.

Search efforts intensified on 20 March, after large pieces of possible debris had been photographed in this area four days earlier by a satellite. Australia, the United States, China, Japan, New Zealand, and South Korea assigned military and civilian ships and aircraft to the search. China published images from satellite Gaofen 1 on 22 March that showed large debris about 120 km (75 mi) south west of the previous sighting. On 26 March, images from French satellites indicated 122 floating objects in the southern Indian Ocean. Thai satellite images published on 27 March showed about 300 floating objects about 200 km (120 mi) from the French satellites' target area. The abundant finds, none yet confirmed to be from the flight, brought the realisation of the prior lack of surveillance over the area, and the vast amounts of marine debris littering the oceans.

Third phase

Deployment of a towed pinger locator for detecting an aircraft's ULB

Revised estimates of the radar track and the aircraft's remaining fuel led to a move of the search 1,100 kilometres (680 mi) north-east of the previous area on 28 March, to a new search area of 319,000 square kilometres (123,000 sq mi), roughly 1,850 kilometres (1,150 mi) west of Perth. This search area had more hospitable weather conditions.

On 30 March, four large orange-coloured objects found by search aircraft, described by media as "the so far most promising lead", turned out to be fishing equipment. On 2 April, the centre of the search area was shifted again 456 kilometres (283 mi) east, to a position 1,504 kilometres (935 mi) west of Perth. The same day, Royal Navy survey vessel HMS Echo and submarine HMS Tireless arrived in the area, with HMS Echo starting immediately to search for the aircraft's underwater locator beacons (ULBs) fitted to the "black box" flight recorders, whose batteries are expected to have expired around 7 April.

Fourth phase

Ocean Shield deploys Bluefin-21, 14 April 2014

On 4 April, the search was refocused to three more northerly areas from 1,060 to 2,100 kilometres (660 to 1,300 mi) west of Learmonth, spanning over 217,000 square kilometres (84,000 sq mi). ADV Ocean Shield, fitted with a TPL-25 towed pinger locator, together with HMS Echo – which carried a "similar device", began searching for pings along a 240 kilometres (150 mi) seabed line believed to be the Flight 370 impact area. Operators considered it a shot in the dark, when comparing the vast search area with the fact that TPL-25 could only search up to 50 square miles (130 km²) per day.

On China's announcement of two unconfirmed acoustic events picked up by Haixun 01 through a handheld hydrophone on 4 and 5 April, the Joint Agency Coordination Centre (JACC) ordered HMS Echo to the area, to attempt verification with more advanced equipment.

On 6 April, JACC announced that Ocean Shield had also picked up a signal, about 300 nautical miles (560 km; 350 mi) from Haixun 01. It was announced the next day that the TPL-25 pinger locator towed by Ocean Shield had picked up a signal twice on 6 April. The first, in the morning of 6 April at approximately 3,000 metres (9,800 ft) depth, lasted 2 hours and 20 minutes; the second episode took place at approximately 300 metres (980 ft) depth with the TPL only in the process of being deployed, and lasted 13 minutes. During the second episode, two distinct pinger returns were audible. Both episodes of recorded signals, which took place at roughly the same position though several kilometres apart, were considered to be consistent with signals expected from an aircraft's flight recorder ULB. The Ocean Shield events were recorded at the north of a newly calculated impact area, which was announced on 7 April, while the Haixun 01 events had been recorded at its southern edge. Ocean Shield detected two more signals on 8 April – the first signal acquired at 16:27 AWST held for 5 minutes, 32 seconds; the second signal was acquired at 22:17 AWST and held for around 7 minutes. Experts had determined that the earlier signals captured by Ocean Shield were "very stable, distinct, and clear ... at 33.331 kHz and ... consistently pulsed at a 1.106-second interval". These were claimed to be consistent with the flight recorder ULB. but the frequency of the detections was well outside the manufacturer's specification of 37.5 +/- 1. The later signals detected, at a frequency of 27kHz, cast further doubt that they were from a black box. On 10 April, a signal recorded by one of the sonobuoys deployed with a hydrophone at 300 metres depth was found unlikely to have originated from Flight 370.

On 14 April, due to the likelihood of the ULBs' acoustic pulses ceasing after their batteries had run down, the Towed Pinger Locator search gave way to a sea-bed search using side-scan sonar installed in the Bluefin-21 Autonomous Underwater Vehicle. The first day's search was aborted because the sea bed was considerably deeper than the maximum operating depth of Bluefin. Scanning resumed after the abortive initial mission.

After covering 42 square miles in its first four dives, the submersible was reprogrammed to allow it to dive 604 feet lower than its limit of 14,800 feet, when the risk of damage was assessed as "acceptable". Ravikumar Madavaram, an aviation expert at Frost & Sullivan Asia Pacific described the search as "definitely the biggest operation ever." The search was then believed to have cost $100 million (£72m) and had been labelled "the costliest in aviation history".

Bluefin-21 required 16 missions to complete its search of the 314 square kilometre area around the detections made by the Towed Pinger Locator. At a news conference in Canberra on 28 April, Tony Abbott said "It is now 52 days since Malaysia Airlines Fight MH370 disappeared and I'm here to inform you that the search will be entering a new phase". Abbott also explained that "a much larger" area of the ocean floor would now be searched; it was "highly unlikely" that any surface wreckage would be found; and that the aerial searches had been suspended. Mission 17 of Bluefin-21, covering the new, wider search area, was on 30 April.

On 12 May, it was reported that the captain of Ocean Shield said there was increasing doubt that pings #3 and #4 detected on 8 April originated with MH370's black boxes because their frequency of about 27 kHz was too far below the pinger's design frequency of 37.5 kHz. Pings #1 and #2, detected on 5 April at 33 kHz, were still being considered by the search authorities as their frequency was closer to 37.5 kHz and because the pinger frequency could have drifted down due to battery exhaustion and environmental conditions such as pressure. However, on 13 May the search was interrupted due to problems with both the transponder mounted on the Ocean Shield and that mounted on Bluefin-21.

International involvement

In response to the incident, the Malaysian government mobilised its civil aviation department, air force, navy, and Maritime Enforcement Agency; and requested international assistance under Five Power Defence Arrangements provisions and from neighbouring states. Various nations mounted a search and rescue mission in the region's waters. Within two days, the countries had already dispatched more than 34 aircraft and 40 ships to the area. The Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission analysed information from its network of infrasound detection stations, but failed to find any sounds made by Flight 370.

On 11 March, the China Meteorological Administration activated the International Charter on Space and Major Disasters, a 15 member organisation whose purpose is to "provide a unified system of space data acquisition and delivery to those affected by natural or man-made disasters," the first time the charitable and humanitarian redeployment of the assorted corporate, national space agency, and international satellite assets under its aegis had been used to search for an airliner.

Another 11 countries joined the search efforts by 17 March, after more assistance was requested by Malaysia. At the peak, before the search was moved to the south Indian Ocean, 26 countries were involved in the search, contributing a total of nearly 60 ships and 50 aircraft. In addition to the above, these parties included Australia, Bangladesh, Brunei, Cambodia, China, France, India, Indonesia, Japan, Myanmar, New Zealand, Norway, Philippines, Russia, Singapore, South Korea, Taiwan, Thailand, United Arab Emirates, United Kingdom, United States, Vietnam. While not participating in the search itself, Sri Lanka gave permission for search aircraft to use its airspace. Malaysia deployed military fixed-wing aircraft and helicopters, and ships. A co-ordination centre at the National Disaster Control Centre (NDCC) in Pulau Meranti, Cyberjaya was established.

On 16 March, three staff members of the French government agency BEA flew to Kuala Lumpur to share with Malaysian authorities their experience in the organisation of undersea searches, acquired during the search for the wreckage of Air France Flight 447.

The United Kingdom provided technical assistance from the Ministry of Defence, the United Kingdom Hydrographic Office, Department for Transport and the Met Office; and personnel from the Royal Air Force.

Ships and aircraft from Australia, China, Japan, Malaysia, New Zealand, South Korea, the United Kingdom and the United States were involved in the search of the southern Indian Ocean.

Information sharing

Although Malaysia's acting Transport Minister Hishammuddin Hussein, who is also the country's Defence Minister, denied the existence of problems between the participating countries, academics said that because of regional conflicts, there were genuine trust issues involved in co-operation and sharing intelligence, and that these were hampering the search. International relations experts said entrenched rivalries over sovereignty, security, intelligence, and national interests made meaningful multilateral co-operation very difficult. A Chinese academic made the observation that the parties were searching independently, thus it was not a multilateral search effort. However, The Guardian noted the Vietnamese permission given for Chinese aircraft to overfly its airspace as a positive sign of co-operation.

Malaysia had initially declined to release raw data from its military radar, deeming the information "too sensitive", but later acceded. Defence experts suggested that giving others access to radar information could be sensitive on a military level. As an example: "The rate at which they can take the picture can also reveal how good the radar system is." One suggested that some countries could already have had radar data on the aircraft but were reluctant to share any information that could potentially reveal their defence capabilities and compromise their own security. Similarly, submarines patrolling the South China Sea might have information in the event of a water impact, and sharing such information could reveal their locations and listening capabilities. This is quite plausible, given how quickly the US redirected USS Kidd to begin searching the Indian Ocean, even as other search assets were then still focused on searching previous search areas.

Satellite imagery was also made available by Tomnod for the public to help with the search through crowdsourcing.

Analysis of satellite communication

The datalink for Malaysia Airline's avionics communications is supplied by SITA, which contracted with Inmarsat to provide a satellite communication link using Inmarsat's Classic Aero service. An aircraft's satellite communication (SATCOM) system is used to transmit messages from the cockpit as well as automated messages from on-board systems using the ACARS communications protocol, but may also be used to transmit FANS & ATN messages and provide voice, fax and data links using other protocols. The SATCOM signals from the aircraft are picked up by Inmarsat's constellation of satellites and relayed to ground stations. In the absence of a signal from a terminal, the ground station transmits hourly 'log on/log off' messages – informally referred to as a 'ping' – to the terminal; an active terminal automatically responds. The entire process is referred to as a 'handshake'. After ACARS equipment on the aircraft was disabled, the SATCOM transceiver aboard Flight 370 completed six further handshakes; the final complete handshake occurring at 00:11 UTC on 8 March (08:11 MYT).

Although the ACARS system on Flight 370 was disabled at 01:21 MYT (17:21 UTC, 7 March), the SATCOM terminal remained operable. On 8 March, Inmarsat provided basic flight data relating to Flight 370 to SITA, which relayed information to Malaysia Airlines and investigators. On 9–10 March, Inmarsat engineers noted that the ground station log recorded pings from the aircraft for several hours after contact was lost with air traffic control. An analysis of the time difference between the transmission of the ping and the aircraft's response allowed Inmarsat to determine the aircraft's distance from the satellite resulted in the plotting of two arcs—referred to as the "northern corridor" and "southern corridor" where the aircraft may have been located at the time of its last complete handshake at 00:11 UTC.

Inmarsat conducted further analysis on the signals received during the handshakes, focusing on the frequency shift of the signal emitted from the aircraft compared with the actual frequency received, known as the burst frequency offset, using a baseline of earlier system data for the aircraft, satellite, and ground station. The burst frequency offset, caused by the Doppler effect, varies based on the aircraft's speed and whether it is moving towards or away from the satellite. Using an "innovative technique" that has "never before [been] used in an investigation of this sort", the team determined it could also use the burst frequency offset to determine the aircraft's speed and position along the identified arcs. Inmarsat cross-checked its methodology to known flight data from six Boeing 777 aircraft flying in various directions on the same day, and found a good match. Applying the technique to the handshake signals from Flight 370 gave results that correlated strongly with the expected and actual measurements of a southern trajectory over the Indian Ocean, but poorly with a northern trajectory. Further revised calculations to account for movements of the satellite relative to the earth allowed the northern corridor to be ruled out completely. This analysis was passed on to Malaysian authorities on 23 March. At 22:00 local time the next day, Prime Minister Najib cited this development to conclude that "Flight MH370 ended in the southern Indian Ocean."

In addition to the six completed handshakes between Flight 370 and the ground station after ACARS stopped sending messages, there is "evidence of a partial handshake" at 00:19 UTC which was not immediately well understood and is subject to further investigation. Since the aircraft did not respond to a ping at 01:15 UTC, it was concluded that at some point between 00:11 UTC and 01:15 UTC, the aircraft lost the ability to communicate with the ground station, which Malaysia's Department of Civil Aviation noted was "consistent with the maximum endurance of the aircraft". Of note, the SATCOM terminal on an aircraft requires power from the aircraft to operate.

Malaysian investigators set up an international working group, consisting of various agencies with experience in aircraft performance and satellite communications, to further analyse the signals between Flight 370 and the ground station, especially the signal at 00:19 UTC. These included representatives from the UK's Inmarsat, AAIB and Rolls-Royce; China's Civil Aviation Administration and Aircraft Accident Investigation Department; the US NTSB and FAA, and Malaysian authorities. Also on 7 April, JACC announced that the Malaysian technical investigation team indicated that the partial ping from Flight 370 at 08:19 MYT was most likely when it impacted with the water. Together with further refinement of the satellite data calculation, the investigation team hypothesised a reduced search area.

In an article published on 8 May several satellite experts questioned the analysis of satellite pings made by Inmarsat staff because the Doppler frequency shifts measured were apparently not properly corrected against the satellite's own drift (a periodic North-South oscillation of 3º every 24 hours). Without any additional data being released, the implication of this new analysis was that the northern portion of the Inmarsat satellite pings arc could not be ruled out.

Aircraft

Flightdeck of 9M-MRO in 2004.

Flight 370 was operated with a Boeing 777-2H6ER, serial number 28420, registration 9M-MRO. The 404th Boeing 777 produced, it first flew on 14 May 2002, and was delivered new to Malaysia Airlines on 31 May 2002. The aircraft was powered by two Rolls-Royce Trent 892 engines, and configured to carry 282 passengers. 9M-MRO had accumulated 53,460 hours and 7,525 cycles in service, and had not previously been involved in any major incidents, though a minor incident while taxiing at Shanghai Pudong International Airport in August 2012 resulted in a broken wingtip. Its last maintenance 'A' check was carried out on 23 February 2014.

The Boeing 777, introduced in 1994, is generally regarded by aviation experts as having a safety record that is one of the best of any commercial aircraft. Since its first commercial flight in June 1995, there have been only three other serious accidents involving hull-loss: British Airways Flight 38 in 2008; a cockpit fire in a parked Egyptair 777-200 at Cairo International Airport in 2011; and Asiana Airlines Flight 214 in 2013, in which three people died.

Passengers and crew

People on board by country

Country	No.
Australia	6
Canada	2
China	152
France	4
Hong Kong	1
India	5
Indonesia	7
Iran	2
Malaysia	50
Netherlands	1
New Zealand	2
Russia	1
Taiwan	1
Ukraine	2
United States	3
Total	239

Malaysia Airlines released the names and nationalities of the 227 passengers and 12 crew members, based on the flight manifest, later modified to include two Iranian passengers travelling on stolen passports.

Passengers

152 of the 227 passengers were Chinese citizens, including a group of 19 artists with six family members and four staff returning from a calligraphy exhibition of their work in Kuala Lumpur; 38 passengers were Malaysian. The remaining passengers were from 13 different countries. Of the total, 20 were employees of Freescale Semiconductor, a company based in Austin, Texas – 12 of whom were from Malaysia and 8 from China. One passenger who worked as a flight engineer for a Swiss jet charter company was briefly suspected as potential hijacker because he was thought to have the relevant skill set.

Under a 2007 agreement with Malaysia Airlines, Tzu Chi – an international Buddhist organisation – immediately sent specially trained teams to Beijing and Malaysia to give emotional support to passengers' families. The airline also sent its own team of caregivers and volunteers and agreed to bear the expenses of bringing family members of the passengers to Kuala Lumpur and providing them with accommodation, medical care, and counselling. Altogether, 115 family members of the Chinese passengers flew to Kuala Lumpur. Some other family members chose to remain in China, fearing they would feel too isolated in Malaysia. The airline's offer of an ex gratia condolence payment of US$5,000 to the family of each passenger was initially rejected; the amounts were handed out to relatives on 12 March. It was also reported that Malaysian relatives only received $2,000.

Crew

All the 12 crew members were Malaysian citizens. The flight's captain was 53-year-old Zaharie Ahmad Shah from Penang; he joined MAS in 1981 and had 18,365 hours of flying experience. Zaharie was also an examiner qualified to conduct simulator tests for pilots.

The first officer was 27-year-old Fariq Abdul Hamid, an employee of MAS since 2007, with 2,763 flying hours. This was Fariq's first flight as a fully qualified Boeing 777 first officer, following the completion of his supervised transition to that type of aircraft.

Investigation

International participation

On 8 March, although a formal (ICAO-sanctioned) investigation had not yet started, Boeing announced that it was assembling a team of experts to provide technical assistance to investigators, in accordance with ICAO protocols. The United States National Transportation Safety Board (NTSB) soon thereafter announced it was sending its own team of investigators with technical advisers from the Federal Aviation Administration (FAA).

The United States Federal Bureau of Investigation (FBI) had already deployed technical experts and agents to investigate the disappearance. A senior US law enforcement official clarified that FBI agents had not been sent to Malaysia. By 17 March the investigation was also being assisted by Interpol and other relevant international law enforcement authorities according to the Malaysian government.

On 6 April Malaysia announced it had set up three ministerial committees to help co-ordinate the search, and a new investigation team including members from Australia, China, the US, the UK, and France had been established, being led according to the ICAO standards by "an independent investigator in charge". The investigation into the aircraft's disappearance was Malaysia's responsibility and Australia was co-ordinating the ocean search. Australia, the US, UK, and China had agreed to be "accredited representatives" of the investigation.

Possible passenger involvement

Two men identified on the manifest, an Austrian and an Italian, had reported their passports stolen in 2012 and 2013, respectively. Interpol stated that both passports were listed on its database of lost and stolen passports, and that no check had been made against its database. Malaysia's Home Minister, Ahmad Zahid Hamidi, criticised his country's immigration officials for failing to stop the passengers travelling on the stolen European passports. The two one-way tickets purchased for the holders of the stolen passports were booked through China Southern Airlines. It was reported that an Iranian had ordered the cheapest tickets to Europe via telephone in Bangkok, Thailand. The tickets were paid for in cash. The two passengers were later identified as Iranian men, one aged 19 and the other 29, who had entered Malaysia on 28 February using valid Iranian passports. The head of Interpol said the organisation was "inclined to conclude that it was not a terrorist incident". The two men were believed to be asylum seekers. United States and Malaysian officials were reviewing the backgrounds of every passenger named on the manifest. On 18 March the Chinese government announced that it had checked all of the Chinese citizens on the aircraft and ruled out the possibility that any were potential hijackers.

Crew and cargo

Police searched the homes of the pilot and co-pilot, on suspicion that those in the cockpit had been responsible for the aircraft's disappearance. However, no evidence had emerged to support this theory. After the FBI reconstructed the deleted data from the pilot's home flight simulator, the Malaysian government spokesman indicated that "nothing sinister" had been found on it.

Malaysia Airlines disclosed its cargo manifest on 1 May. On 17 March, MAS chief executive, Ahmad Jauhari Yahya, indicated only that the aircraft was carrying 3 to 4 tonnes/tons of mangosteens and said that nothing it transported was dangerous. Three days later, he also confirmed that potentially flammable batteries, identified as lithium-ion, were on board, adding that all cargo was "packed as recommended by the ICAO", checked several times, and deemed to meet regulations. The cargo manifest released on 1 May had revealed two air waybills (AWBs) for lithium-ion batteries with a total consignment weight of 221 kg. Three other AWBs weighing 2,232 kg, were declared as radio accessories and chargers, but an MAS representative said he was not permitted to provide additional information.

On 2 April Khalid Abu Bakar, Malaysia's Police Inspector-General, said that as part of its ongoing criminal investigation, more than 170 interviews had been conducted, including with family members of the pilots and crew. Khalid said that the provenance and destination of all cargo, including the mangosteens and in-flight meals, were being investigated to rule out sabotage as a cause.

Claims of responsibility

On 9 March 2014, members of the Chinese news media received an open letter that claimed to be from the leader of the Chinese Martyrs Brigade, a previously unheard of group. The letter claimed that the loss of flight MH370 was in retaliation for the Chinese government's response to the knife attacks at Kunming railway station on 1 March 2014 and part of the wider separatist campaign against Chinese control over Xinjiang province's Uyghur regions. The letter also listed unspecified grievances against the Malaysian government. The letter's claim was dismissed as fraudulent based on its lack of detail regarding the fate of MH370 and the fact that the name "Chinese Martyrs Brigade" appeared inconsistent with Uyghur separatist groups which describe themselves as "East Turkestan" and "Islamic" rather than "Chinese".

Criticism and response

Public communication from Malaysian officials regarding the loss of the flight was initially beset with confusion. The New York Times wrote that the Malaysian government and the airline released imprecise, incomplete, and sometimes inaccurate information, with civilian officials sometimes contradicting military leaders. Malaysian officials were also criticised after the persistent release of contradictory information, most notably regarding the last point and time of contact with the aircraft.

Vietnam temporarily scaled back its search operations after the country's Deputy Transport Minister cited a lack of communication from Malaysian officials despite requests for more information. China, through the official Xinhua News Agency, said that the Malaysian government ought to take charge and conduct the operation with greater transparency, a point echoed by the Chinese Foreign Ministry days later.

On 11 March, three days after the aircraft disappeared, British satellite company Inmarsat had provided officials (or its partner, SITA) with data suggesting the aircraft was nowhere near the areas in the Gulf of Thailand and the South China Sea being searched at that time; and may have diverted its course through a southern or northern corridor. This information was only publicly acknowledged and released by Najib on 15 March in a press conference.

Questions and criticisms were raised by air force experts and the Malaysian opposition about the current state of Malaysia's air force and radar capabilities. Opposition leader Anwar Ibrahim said it was impossible and unacceptable that the country's advanced British radar system and military readiness had not been triggered by such a diverted flight.

On 14 March, Malaysia Airlines retired the MH370/MH371 flight number pair for the Kuala Lumpur–Beijing–Kuala Lumpur route, replacing them with MH318 and MH319 respectively.

On 24 March, Chinese Deputy Foreign Minister Xie Hangsheng reacted sceptically to the conclusion by the Malaysian government that the aircraft had gone down with no survivors. Xie Hangsheng demanded "all the relevant information and evidence about the satellite data analysis", and said that the Malaysian government must "finish all the work including search and rescue."

Criticism was also levelled at the delay of the search efforts. Explaining why information about satellite signals had not been made available earlier, Malaysia Airlines said that the raw satellite signals needed to be verified and analysed "so that their significance could be properly understood" before it could publicly confirm their existence. Hishammuddin said Malaysian and US investigators had immediately discussed the Inmarsat data upon receiving them on 12 March, and on two occasions, both groups agreed that it needed further processing and sent the data to the US twice for this purpose. Data analysis was completed on 14 March: by then, the AAIB had independently arrived at the same conclusion.

On 25 March, Chinese president Xi Jinping said he was sending a special envoy to Kuala Lumpur to consult with the Malaysian government over the missing aircraft. The same day, around two hundred family members of the Chinese passengers protested outside the Malaysian embassy in Beijing. Relatives who had arrived in Kuala Lumpur after the announcement continued with their protest, accusing Malaysia of hiding the truth and harbouring the murderer. They also wanted an apology for the Malaysian government's poor initial handling of the disaster and its "premature" conclusion of loss, drawn without physical evidence. An op-ed for China Daily said that Malaysia was not wholly to be blamed for its poor handling of such a "bizarre and unprecedented crisis", and appealed to Chinese people not to allow emotions to prevail over evidence and rationality. The Chinese ambassador to Malaysia rebuked the "radical and irresponsible opinions" of the Chinese relatives, and said that they "[did] not represent the views of Chinese people and the Chinese government". The ambassador also strongly criticised Western media for having "published false news, stoked conflict and even spread rumours" to the detriment of relatives and of Sino–Malaysian relations. On the other hand, an article in the The New York Times criticized China for providing apparently false leads that detracted from the search effort and wasted time and resources.

Timeline of events

Date (UTC)	Category	Event
7 March	Media	Department of Civil Aviation (DCA) Malaysia and Malaysia Airlines confirm Subang Air Traffic Control outside Kuala Lumpur lost contact with Malaysia Airlines Flight 370 on 8 March 2014 at 02:40 local time (on 7 March 2014 at 18:40 UTC), later corrected to 01:30 local time (17:30 UTC) located at 6°33′05″N 103°20′39″E
	Search	Malaysian and Vietnamese authorities jointly searching in the Gulf of Thailand area; China dispatches two maritime rescue ships to the South China Sea.
8 March	Search	An international search and rescue mission mobilised, focusing on Gulf of Thailand. Natuna Islands archipelago and South China Sea. Malaysia, Vietnam, China, Singapore and Indonesia.
	Media	Malaysia Airlines releases passenger manifest of Malaysia Airlines Flight 370.
		Two men from Austria and Italy, listed among the passengers on Flight 370, are not in fact on board. Officials in both countries say that each had his passport stolen.
9 March	Search	The search zone expanded, to include areas in the Strait of Malacca as military radar tracking indicates aircraft might have turned west from its flight plan and flight path.
	Investigation	INTERPOL confirms that at least two passengers are found to have been travelling on stolen passports registered in its databases.
10 March	Search	Ten Chinese satellites deployed in the search. Oil slicks on the surface of the South China Sea test negative for jet fuel.
	Media	Malaysia Airlines announces it will give US$5,000 to the relatives of each passenger.
11 March	Investigation	INTERPOL says that two false identities are not linked to the disappearance.
	Media	China activates the International Charter on Space and Major Disasters.
12 March	Search	Chinese satellite images of possible debris from Flight 370 in the South China Sea at 6.7°N 105.63°E / 6.7; 105.63 (Possible debris, 12 March) released, but surface search finds no wreckage. Malaysian government receives Inmarsat info that Flight 370 pinged for hours after ACARS went off-line.
	Media	Chinese government criticises Malaysia for inadequate answers regarding Flight 370.
	Investigation	Royal Malaysian Air Force chief says that an aircraft plotted on military radar crossed the Malaysian states of Pahang, Terengganu, Selangor, Perak and Penang after changing course, towards a waypoint called GIVAL at 2:15 local time (18:15 UTC, 7 March), 200 miles (320 km) northwest of Penang Island off Malaysia's west coast. It followed standard aviation corridors. Search and rescue efforts being stepped up in Andaman Sea and Bay of Bengal.
14 March	Investigation	Investigation concludes that Flight 370 was still under human control after it lost ground control contact.
	Media	MAS retires the MH370/MH371 flight number pair.
15 March	Search	New phase of multi-national search and rescue operations within two areas in the northern and southern "corridors". Twenty-six countries involved, among the northern corridor countries are Kazakhstan, Turkmenistan, China, Thailand, including South China Sea and Gulf of Thailand. The southern corridor covers Indonesia, Australia, and the Indian Ocean.
		India continues search for Malaysia Airlines Flight 370; Malaysia ends hunt in South China Sea.
	Investigation	Malaysian police search the homes of both of the aircraft's pilots.
16 March	Search	Twenty-five countries are involved in the search. India ends its search in the Andaman Sea and Bay of Bengal.
17 March	Search	Search area reported by Malaysian authorities to be 2,000,000 square miles (5,200,000 km2), as a belt beneath the last possible arc position stretching from Kazakhstan over Indonesia to the southern part of the Indian Ocean. Australia pledges to lead a search from Sumatra to the southern Indian Ocean.
18 March	Search	China starts a search operation in its own territory. Australia conducts an aerial search through waters West and North of Cocos Islands and Christmas Island (close to Indonesia). Australia also conducts its first aerial search of the southern Indian Ocean, roughly 3,000 kilometres (1,900 mi) southwest of Perth.
19 March	Search	Australia searches the southern Indian Ocean with three aircraft and three merchant ships, transiting through a slightly revised search area of 305,000 square kilometres (118,000 sq mi) about 2,600 kilometres (1,600 mi) southwest of Perth.
20 March	Media	Prime minister of Australia, Tony Abbott, told parliament that the "new and credible information" had emerged from expert analysis of satellite imagery.
	Search	Five aircraft and a fourth (merchant) ship are dispatched to 44°03′02″S 91°13′27″E.
22 March	Search	Chinese satellite image taken on 18 March shows a possible object measuring 22.5 by 13 metres (74 by 43 ft) at 44°57′30″S 90°13′40″E, approximately 3,170 kilometres (1,970 mi) west of Perth and 120 kilometres (75 mi) from the earlier sighting, but did not confirm the object's nature.
24 March	Media	Prime Minister of Malaysia announces that Flight 370 is assumed to have gone down in the southern Indian Ocean; Malaysia Airlines states to families that it assumes "beyond reasonable doubt" there are no survivors.
	Search	Search area narrowed to the southern part of the Indian Ocean west and southwest of Australia. The northern search corridor (northwest of Malaysia) and the northern half of the southern search corridor (the waters between Indonesia and Australia) are definitively ruled out. An Australian search aircraft spots two objects at sea, 1,550 miles (2,490 km) southwest of Perth.
26 March	Search	French satellite images captured on 23 March show 122 possible pieces of debris at 44°41′24″S 90°25′19.20″E, 44°41′38.45″S 90°29′31.20″E and 44°40′10.20″S 90°36′25.20″E.
	Media	UK Air Accidents Investigation Branch (AAIB) heads a team of investigators from other states as part of an international effort supporting the Malaysian authorities in accordance with the International Civil Aviation Organization (ICAO) code.
27 March	Search	The search area narrows to roughly 76,000 square kilometres (29,000 sq mi). Thai and Japanese satellite images, captured 24–26 March show floating objects 200 kilometres (120 mi) south of the French observations. Five ships from Australia and China are engaged.
28 March	Search	Search shifts to a new 319,000-square-kilometre (123,000 sq mi) area 1,100 kilometres (680 mi) northeast of the previous search area.
29 March	Media	Malaysia announces that an international panel will be formed under United Nations protocols to investigate the Flight 370 incident.
30 March	Media	Prime Minister of Australia announces newly formed Joint Agency Coordination Centre (JACC) headed by Angus Houston. Military air crew from Australia, China, Japan, Malaysia, New Zealand, South Korea, and the United States are actively engaged.
5 April	Search	Chinese patrol ship Haixun 01 detects a pulse signal at 25°S 101°E. Ocean Shield also picks up two longer lasting signals.
8 April	Search	Ocean Shield picks up two further signals 3,500 metres deep, close to those of 5 April.
10 April	Search	Another signal is acquired by a sonobuoy deployed near the Ocean Shield signal acquisitions. JACC declares the contact unlikely to be related to Flight 370. Hydrographic survey ship HMS Echo arrives on scene to provide advanced computer analysis of Ocean Shield collected sonar data and to measure the thermoclines in the area to predict the trajectory of the detected pings.
14 April	Search	An oil slick is found 5.5 km from the estimated location of the pings by Ocean Shield. Ocean Shield ceases towed passive sonar operations; the AUV Bluefin-21 is deployed with side-scan sonar to search for wreckage on the ocean floor, but its mission is automatically aborted on reaching its maximum operating depth.
15 April	Search	Bluefin-21 resumes scanning after its abortive initial mission.
18 April	Search	The oil slick discovered four days earlier is determined by an Australian laboratory analysis not to be related to Flight 370.
24 April	Search	Debris consisting of riveted metal sheets washes up on the Western Australian coast. This is later confirmed to be unrelated to Flight 370.
28 April	Search	PM Abbott and Angus Houston of JACC announce that a larger area of the ocean floor would now be searched and there would be a suspension of the aerial search due to the likelihood that any wreckage would have sunk.
5 May	Search	The US Navy extends contract for Bluefin-21 by four weeks.
12 May	Search	Searchers say two of the four 'pings' they thought were from flight recorder ULBs may not have been from the flight recorder.
22 May	Search	Bluefin-21 resumes its search after it is repaired .

See also

• Malaysia Airlines Flight 370 conspiracy theories
• Zenith Plateau

External links

• Accident description at the Aviation Safety Network
• Preliminary Report - Preliminary report issued by the Malaysia Ministry of Transport. Dated 9 April 2014 and released publicly on 1 May 2014.
• Prime Minister of Malaysia Press Releases.
• Malaysian Ministry of Transport: Press Statements and Briefings from the Prime Minister, Minister of Defence and acting Minister of Transport, Director General of the Department of Civil Aviation and Director General of Immigration. Includes transcripts of questions and answers not available on other external links.
• Updates regarding MH370 from Malaysia Airlines
• Australian Maritime Safety Authority MH370 Search Media Kit Original Briefings and charts etc. for the MH370 search in the Australian area. Includes MP3 and MP4 videos of Media Briefings. From 1 April 2014, communication regarding the MH370 search were issued by the Joint Agency Coordination Centre (JACC). The AMSA site does however include all charts, including those after 1 April.
• JACC: Media releases, press conference transcripts.
• US Department of Defense – MH370: news & photos regarding MH370 from the US Department of Defense (content is in the public domain)