An extensive search continues for the missing Malaysia Airlines plane. What authorities say is known:
— The Boeing 777 carrying 239 people lost contact over the sea between Malaysia and Vietnam; there was no sign of trouble when it flew across Malaysia into the Gulf of Thailand at 35,000 feet before it disappeared early Saturday.
— The last technical data received from Flight 370 had come at 1:07 a.m. Saturday, when the aircraft was still in touch with ground controllers, and there was no indication of trouble with the plane.
— US and Malaysian officials have said the Malaysia Airlines plane sent signals for hours after the aircraft went missing.
— The hunt has been punctuated by false leads, the latest Thursday when planes were sent to search the area where Chinese satellite images showed smoke off the southern tip of Vietnam.
— The Malaysian military says it has radar evidence showing the missing jet changed course and made it to the Malacca Strait, hundreds of miles away from the last location reported by civilian authorities.
— Some 43 ships and 39 aircraft from at least eight nations are scouring an area of 35,800 square miles, or about the size of Portugal.
What is not yet known:
— What happened to cause the plane to lose contact. Catastrophic failure of the engines or plane structure, extreme turbulence or pilot error or even suicide, are possible.
— Both the Boeing 777 and Malaysia Airlines have excellent safety records. Until wreckage or debris is found and examined, it will be very hard to say what happened.
— Malaysian authorities acknowledged that they were unsure which direction the plane was headed when it disappeared.
— The government said on the day of the plane’s disappearance that there were indications it attempted to turn back, but didn’t say what they were.