The disappearance of Malaysian Airline System Bhd.’s Flight 370 has 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:
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 cockpit. Initial investigation says copilot said, “alright, good night” as the last words. 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 with Flight 370. Chinese passengers make up about two-thirds of the people on board the plane.
8:11 a.m.: Last satellite signal from plane is detected. This development won’t be known for about a week.
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. The discovery that two passengers were traveling on stolen passports triggers speculation that terrorism may have been involved.
March 9: Vietnamese searchers find objects in the Gulf of Thailand only to conclude later that they’re unrelated to Flight 370. Representatives for the U.S. National Transportation Safety Board, Federal Aviation Administration and Boeing travel to Malaysia to assist with the investigation. Speculation arises that the plane deviated from its route.
March 10: Malaysia expands the search area farther into the South China Sea and sends ships to examine suspected plane debris near Hong Kong. Vietnam searchers look for a suspected window piece that was spotted from the air. The leads prove fruitless. Searchers are unable to locate a yellow inflatable object that a Vietnamese helicopter spotted earlier.
March 11: The search expands east again as suspected debris is found off the coast of Vietnam. One theory evaporates as authorities in Malaysia and Interpol say the passengers with stolen passports probably aren’t associated with terrorism.
March 12: Malaysia says a criminal probe is looking into hijacking and sabotage among other theories. Vietnam says Malaysia hasn’t been cooperative in search and that the flight may have turned west after last signal. News reports surface that the co-pilot had guests in the cockpit in a previous flight.
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.
The shift in focus follows a brief flurry of optimism for a breakthrough. Chinese satellite images show floating objects between the South China Sea and the Gulf of Thailand, and the Malaysian government says later that they are unrelated to Flight 370.
March 14: The Andaman Sea becomes the latest empty lead in the search. Malaysia looks at the possibility of pilot and crew involvement, while Prime Minister Najib Razak postpones a trip to Qatar and the United Arab Emirates to oversee the hunt.
March 15: Satellite transmissions trace the missing airliner to the Indian Ocean off of Australia. The pilots’ homes are searched, and Najib says new information shows the flight was intentionally diverted.
March 16: Searchers shift their sights to the Indian Ocean on the basis of the satellite-signals evidence, which shows that the plane operated for about seven hours after its last contact with air traffic control.
March 17: Australia leads the search in the Indian Ocean while the law enforcement probe spreads across multiple fronts. Authorities discuss pilot suicide as one possibility, police investigate a flight engineer who was a passenger.
March 18: The disappearance becomes the longest in modern aviation history. The U.S. joins Australia in the Indian Ocean search, scanning the waters across an area 1 1/2 times as big as California.
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. An analysis of the 777’s probable fuel reserves helps narrow the Indian Ocean search area to a patrol zone about the size of Italy, half as big as a day earlier.
March 20: Satellite images of objects off Australia’s west coast spur an air-and-sea search across a remote stretch of the Indian Ocean. The photos were taken on March 16, and patrol craft aren’t able to locate any wreckage.
March 21: A second day of air searches turns up nothing. An analysis of so-called pings from the aircraft by satellite provider Inmarsat Plc (ISAT) 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 22: As the mystery reaches the two-week mark and a day of air and sea patrols produces nothing more promising than a sighting of a wooden pallet, China announces that scrutiny of satellite scans has revealed a new image of a large structure in the search zone. The photo, captured on March 18, appears to show an object measuring 22 meters by 13 meters floating 120 kilometers to the southwest of those in the March 16 images.
March 23: Malaysian authorities disclose that a French satellite has found radar traces of possible debris, without saying when and where the images were captured. Search efforts off Australia fail to produce a breakthrough as more aircraft join the hunt and ships with specialist equipment begin to arrive.
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: Air-sea patrols led by Australia and including planes and ships from the U.S., China and New Zealand are resuming.