Flight data suggests someone in cockpit pushed Boeing 737-800 into near-vertical descent, according to a preliminary U.S. assessment of what led to the accident.
The Boeing 737-800 was cruising at high altitude when it suddenly pitched into a near-vertical descent, plummeting into a mountain at extreme speed. Data from a black box recovered in the crash suggests inputs to the controls pushed the plane into the fatal dive, these people said.
“The plane did what it was told to do by someone in the cockpit,” said a person who is familiar with American officials’ preliminary assessment, which includes an analysis of information extracted from the plane’s damaged flight-data recorder.
Also underpinning the American officials’ assessment, this person said: Chinese authorities, who are leading the investigation, so far haven’t flagged any mechanical or flight-control problems with the plane involved in the March 21 crash in southern China. That model is a workhorse of the global aviation industry and is part of a family of Boeing aircraft that have one of the best safety records in commercial flying.
The information gathered so far in the China Eastern probe has led U.S. officials involved with the investigation to turn their attention to the actions of a pilot, people familiar with the matter said. There is also a possibility that someone else on the plane could have broken into the cockpit and deliberately caused the crash, these people said.
Neither Boeing Co. nor air-safety regulators have been working on any service bulletins or safety directives stemming from the crash, people familiar with the matter said. Such messages would be used if authorities believed there was a need to alert airlines and pilots to problems the flight crew encountered in the accident or detail needed fixes to the aircraft.
Accident investigations can turn up previously unknown evidence that can bolster or undermine preliminary assessments. One person familiar with the U.S. officials’ preliminary assessment said the Americans don’t have all information available to their Chinese counterparts.