Perth- Australian investigators concluded today that Malaysia Airlines Flight 370, which veered off course and disappeared on March 8, 2014 was probably not seriously damaged in the air and remained in controlled flight for hours after contact with it was lost , until it ran out of fuel over the southern Indian Ocean. 
Their conclusion, reached in the past few weeks, helped prompt the decision to move the focus of the search hundreds of miles to the southwest. 
The main evidence for the conclusion lies in a re-examination of Malaysian military radar data and in a more detailed analysis of electronic "handshakes," or pings, that the aircraft exchanged with an Immersed satellite over the Equator, senior officials involved in the investigation said. The altitude readings from the radar now appear to have been inaccurate, officials said.

The radar tracked the aircraft, a Boeing 777-200 with 239 people aboard, as it turned sharply off its scheduled northeastward flight path over the Gulf of Thailand and flew west across Peninsular Malaysia and the Strait of Malacca.

The plane then passed beyond radar range near the northern tip of the Indonesian island of Sumatra. Initial reports about the radar readings suggested that along the way, the plane soared as high as 45,000 feet, above its certified maximum altitude of 43,100 feet, and then zoomed down low over the mountains of Malaysia before climbing back to 23,000 feet or higher over the Strait of Malacca. 

But a comprehensive international review has found that the Malaysian radar equipment had not been calibrated with enough precision to draw any conclusions about the aircraft's true altitude. "The primary radar data pertaining to altitude is regarded as unreliable," said Angus Houston, the retired head of the Australian military who is now coordinating the search. 

Houston said in a telephone interview that it was clearly possible that at some point during the tracked part of the flight , the plane flew at 23,000 feet. But he said he doubted whether anyone could prove that the plane had soared and swooped the way the initial reports suggested. 

Martin Dolan, the chief commissioner of the Australian Transport Safety Bureau, agreed with Houston. "There's nothing reliable about height," he said in an interview in his office here in the Australian capital.