The disappearance of Malaysia Airlines Flight 370 galvanized a multinational search, spawned theories ranging from an accident to air piracy and repeatedly dashed hopes that a resolution was at hand.
Below is a timeline of the events that began with the jet’s departure from Kuala Lumpur en route to Beijing:
March 8, 2014:
12:41 a.m.: Flight 370 takes off from Kuala Lumpur to Beijing with 239 passengers and crew members on board.
1:07 a.m.: Last transmission from the Boeing Co. 777-200ER via an onboard text-and-data messaging system known by the acronym Acars.
1:19 a.m.: Last communication from the cockpit. Transcript released April 1 said the last words were “Good Night Malaysian Three Seven Zero.” Plane leaves Malaysian airspace, heading across the Gulf of Thailand toward Vietnam.
1:21 a.m.: Radar transponder is switched off.
1:37 a.m.: Next Acars transmission is due, and never comes.
2:15 a.m.: Malaysian military radar spots an aircraft on the west side of Peninsular Malaysia that isn’t using its transponder. This development won’t be publicly known until about a week later. The radar target is Flight 370, heading away from its planned route.
6:30 a.m.: Flight 370 is scheduled to arrive in Beijing.
7:39 a.m.: China’s Xinhua news agency sends a flash bulletin saying contact had been lost. Chinese passengers make up about two-thirds of the people on board.
8:11 a.m.: Last satellite signal sent from the plane, known as a “handshake,” is detected. This development won’t be known for about a week.
8:19 a.m.: Evidence of a “partial handshake” between the aircraft and the ground station eight minutes after the last complete communication. This information was released March 25.
9:15 a.m.: No response from the aircraft when the ground station sent the next message, indicating the plane was no longer logged on to the network.
Initial search efforts focus on the Gulf of Thailand, where twin oil slicks stir concern that they signal a crash on the plane’s known route.
March 9: Speculation arises that the plane deviated from its route.
March 10: Malaysia expands the search area further into the South China Sea after a plane alerted Hong Kong air traffic controllers about possible debris.
March 11: The search expands east again as suspected debris is found off the coast of Vietnam.
March 12: Vietnam says the flight may have turned west after the last signal.
March 13: Speculation of the crash’s location moves toward the Indian Ocean as evidence mounts that the flight continued away from its route after controllers lost radar contact.
March 14: The Andaman Sea becomes the latest empty lead in the search. Malaysia looks at the possibility of pilot and crew involvement.
March 15: Satellite transmissions trace the missing airliner to the Indian Ocean off of Australia. The pilots’ homes are searched, and Prime Minister Najib Razak says new information shows the flight was intentionally diverted.
March 16: Evidence from satellite-signals shows that the plane operated for about seven hours after its last contact with air traffic control.
March 18: The disappearance becomes the longest in modern aviation history. The U.S. joins Australia in the Indian Ocean search.
March 19: The U.S. Federal Bureau of Investigation joins Malaysia’s inquiry, which now includes a probe of data removed from the pilot’s home flight simulator on Feb. 3.
March 21: An analysis of so-called pings from the aircraft by satellite provider Inmarsat Plc concludes that the plane maintained a steady course and speed after radar contact was lost. The assessment is consistent with details suggesting that the plane was commanded, at least initially, from the cockpit and not disabled by an accident.
March 24: Najib, the prime minister, says Malaysia has concluded the flight ended in the Indian Ocean “far from any possible landing sites,” ruling out theories of a detour over Asia or an island landing.
March 25: Families and friends of Chinese passengers protest in front of the Malaysian embassy in Beijing.
March 28: The hunt for Flight 370 focuses on a new area in the Indian Ocean after radar data indicate the plane probably flew a shorter distance than earlier estimated. The new zone is about 1,100 kilometers to the northeast of the previous search location.
April 1: Malaysia releases the full transcript of communications between Flight 370 and Kuala Lumpur’s air traffic control, which the government says reveals nothing abnormal.
April 4: From surface vessels, crews start underwater scouring of the southern Indian Ocean for pings emitted by the aircraft’s black box as their batteries near the end of their 30-day lifespan.
April 5: Chinese patrol ship Haixun 01 detects a pulse signal with a frequency of 37.5 kilohertz while searching in the southern Indian Ocean, the official Xinhua News Agency reports. While underwater locator beacons transmit at that frequency, the signal could not be confirmed as related to Flight 370. It later detects a second, longer, unidentified signal.
April 6: As many as 12 planes and 13 ships search for the plane’s wreckage on the 30th day after it went missing, with the black boxes’ power supply due to run out.
April 7: Australia says the towed pinger-locator on ship Ocean Shield detected a first signal for two hours and 20 minutes, and a second one for 13 minutes over the weekend. The signals were heard about 600 kilometers northeast of where Haixun 01 picked up sounds earlier.
April 14: With the batteries in the aircraft’s black boxes likely dead, an unmanned submarine known as Bluefin-21, which uses side-scan sonar to capture images of the ocean bottom, is launched to search for plane.
May 1: Government documents show air-traffic controllers and Malaysia Airlines struggled for hours to understand what was happening on the day MH370 vanished, even as the country’s military watched the plane appear to reverse course. Malaysia Airlines says it will make advance payments to the next of kin.
May 28: The search is suspended for about three months as investigators assemble a better survey of the seabed.
May 29: Officials say the deep-sea hunt focused on the wrong place for almost two months.
June 26: Investigators say they’ll shift focus to a new location south of previous searches. Once started, they say, the search could take as long as 12 months.
Sept. 11: The deep-sea sonar search resumes in a 60,000 square-kilometer zone off the coast of Western Australia.
Jan. 29: Malaysia declares Flight 370 an accident and all 239 people on board presumed dead to help families obtain assistance, including compensation.
March 8, 2015: Families of those aboard MH370 hold vigils and protests to mark one year since the plane’s disappearance.
July 29: French officials on Reunion Island notify the Australian Transport Safety Bureau of the discovery of what appears to be part of a plane wing. Based on photos, the wreckage appears to have come from a Boeing 777, the same model as MH370, a person familiar with the investigation says.
July 30: Malaysia Airlines and Prime Minister Najib Razak say it’s too early to speculate on the origins of the part, which is being sent to a lab in Toulouse, France.
August 6: Najib confirmed that the part, a flaperon, came from MH370. A suitcase discovered near the debris also will be studied.
Dec. 3: Australia says two thirds of the new 'hot spot' area has been searched.
Dec. 16: The European Union announces that black boxes on airliners will have to operate for 90 days instead of 30 days as of mid-2018, under new EU regulations. In addition, airlines will have to track their aircraft over oceans as of end-2018 and cockpit voice recorders will have to register conversations for 25 hours instead of two hours as of January 2021.
Jan. 13, 2016: The Australian Transport Safety Bureau announces that the team investigating the disappearance won’t expand its search zone without new clues about the wreck’s exact location.
Jan. 14: The brother of an American MH370 passenger sues the carrier in a U.S. Court. Thomas Wood is seeking as much as the $155,937 maximum automatically allowed under the terms of the 1999 Montreal Convention, and more unless Malaysia Airlines can prove his brother’s death was caused by something other than the negligence of the carrier or those in its employ.
Jan. 23: A chunk of barnacle-encrusted metal, measuring about 2 meters by 3 meters, is found by fishermen in the Gulf of Thailand. But investigations by Thai and Malaysian authorities dash hopes that the debris came from MH370.
Jan. 24: In a sign of the difficulty of the search, one of the vessels combing the sea floor loses its deep-sea sonar vehicle.
About June: The search for MH370 is expected to end after almost two years if no new evidence is found.