SEPANG, Malaysia — Malaysia Airlines Flight 370 experienced significant changes in altitude after it lost contact with ground control, and it altered its course more than once as if still under the command of a pilot, the New York Times reported Friday, citing unnamed U.S. officials and others familiar with the investigation.
Radar signals recorded by the Malaysian military appeared to show that the missing airliner climbed to 45,000 feet, above the approved altitude limit for a Boeing 777-200, soon after it disappeared from civilian radar and turned to the west, according to a preliminary assessment by a person familiar with the data. The person and others spoke to the New York Times on condition of anonymity because they were not authorized to speak publicly.
The radar track, which the Malaysian government has not released but says it has provided to the United States and China, showed the plane then descended unevenly to 23,000 feet, below normal cruising levels, as it approached the island of Penang on the northwest coast of Peninsular Malaysia.
There, officials believe, the plane turned from a southwest-bound course, climbed to a higher altitude and flew northwest toward the Indian Ocean.
Investigators have also examined data transmitted from the plane's Rolls-Royce engines that showed it descended 40,000 feet in the span of a minute, according to a senior U.S. official briefed on the investigation. But investigators do not believe the readings are accurate because the aircraft would likely have taken longer to fall such a distance.
The data, while incomplete and difficult to interpret, could still provide critical new clues as investigators try to determine what happened on Flight 370, which disappeared early March 8 carrying 239 people from Kuala Lumpur, Malaysia, to Beijing.
Malaysian and international investigators have said in recent days that the plane may have departed from its northerly route toward Beijing and headed west across Peninsular Malaysia just after the aircraft disappeared from civilian radar, its pilots stopped communicating with ground controllers, and its transponders stopped transmitting data about its speed and location.
The plane is also now thought to have continued flying for more than four hours after diverting its course, based on automated pings sent by onboard systems to satellites.
But the Malaysian military radar data, which local authorities have declined to provide to the public, added significant new information about the flight immediately after ground controllers lost contact. The combination of altitude changes and at least two significant course corrections could have a variety of explanations, including that a pilot or a hijacker diverted the plane or that it flew unevenly without a pilot after the crew became disabled.
The erratic movements of the aircraft after it diverted course and flew over Malaysia also raise questions about why the military did not respond. Malaysian officials have acknowledged that military radar may have detected the plane but have said they took no action because it did not appear hostile.