According to individuals acquainted with US officials’ first assessment, flight data from a black box recovered from the China Eastern Airlines plane that crashed in March indicates someone in the cockpit purposefully crashed the plane.

After a preliminary inquiry revealed no evidence of a technical breakdown, a Western official stated that the focus is now on the crew’s behaviour.

Boeing, the plane’s manufacturer, declined to comment and referred any questions to Chinese authorities. The National Transportation Safety Board (NTSB) of the United States did not respond promptly.

The Boeing 737-800 jet, en route from Kunming to Guangzhou, crashed in the Guangxi highlands in March after a precipitous descent from cruising altitude, killing all 123 passengers and nine staff members on board. It was the deadliest aircraft tragedy in mainland China in 28 years.

China Eastern began flying the 737-800 planes again in mid-April. Chinese regulators did not mention any technical recommendations in a summary of their preliminary crash study released last month, despite the fact that the 737-800 has been in service since 1997 and has a great safety record, according to experts.

In a May 10 Reuters interview, NTSB Chair Jennifer Homendy claimed that board investigators and Boeing had come to China to assist the Chinese inquiry. She stated that the study had uncovered no safety hazards that required immediate attention.

If the board has any safety concerns, Homendy said the board will “make urgent safety recommendations.”