The crash, China’s first deadly air accident since 2010, killed 132 people.

In a statement on its preliminary crash report, the Civil Aviation Administration of China (CAAC) did not make public any information from the flight data recorder and cockpit voice recorder that were sent to Washington for analysis.

CAAC said the flight crew were qualified, the jet was properly maintained and the weather was fine when flight MU5735, which was en route from Kunming to Guangzhou, plunged from cruising altitude and crashed in the mountains of Guangxi on March 21.

The last normal call from air traffic controllers to the plane was at 2.16pm local time while it was cruising at 8,900m, less than five minutes before the plane began to deviate from its normal path as tracked by controllers in Guangzhou, the CAAC statement said.

At 2.21pm, the last information recorded on radar before the signal disappeared had the plane at an altitude of 3,380m, a ground speed of 1,010kph and a heading of 117°.

Flight tracking website FlightRadar24’s last data, recorded nearly a minute later, had the plane at an altitude of 3,225 feet, a ground speed of 376 miles per hour and a heading of 87°.

CAAC said it had completed the preliminary report, which according to international rules must be filed to United Nations aviation agency Icao within 30 days. A final report could take a year or more to complete.