All 123 passengers and nine crew died when the flight from Kunming to Guangzhou dived from a cruising altitude of 8,900 metres (29,200 feet) and plunged into a hillside in Guangxi region.

The CAAC said the report would not be made public and would not include analyses or conclusions, but Xinhua published a summary on Wednesday, which included much of the information already released by investigators since the accident on March 21.

According to the report, the plane took off at Kunming Changshui International Airport at 1.16pm and climbed to a cruising altitude of 8,900 metres 11 minutes later.

The crew and air traffic control maintained normal radio communication before entering airspace controlled from Guangzhou at 2.17pm.

Less than four minutes later, a warning appeared on the Guangzhou area control radar that the plane had deviated from its assigned altitude. Air traffic control called the crew but did not receive a response.

The plane’s last known position on the radar was recorded at 2.21pm, showing that it was travelling at a ground speed of more than 1,000km an hour (621mph) and was at an altitude of 3,380 metres.

The plane disintegrated upon impact at a valley near Wuzhou city in Guangxi, Xinhua said. A ground scar at the site, which investigators determined as the main impact point, had an area of 45 square metres (484 square feet) and a depth of 2.7 metres (8.9 feet).

The plane’s rudder, horizontal and vertical stabilisers at the tail, its two engines, wings, landing gear, cockpit components and parts of the fuselage were among the main pieces of debris found at the site. However, other parts of the plane have been found up to 12km (8 miles) away.

Xinhua said once all pieces of wreckage were collected, they would be transferred to storage to be cleaned and identified for further analysis.

Xinhua also said the credentials of the maintenance technicians and the cockpit and cabin crews were valid, the required safety checks had been carried out at the right time and the plane was certified to be airworthy.

Before the ill-fated flight, there were no reports of malfunctions, and no dangerous goods were declared as cargo, Xinhua said. The weather forecast did not indicate there was any danger to the flight.

“The technical investigation team will continue to carry out in-depth wreckage identification, classification and inspection, flight data analysis, necessary tests and other investigative work, to determine the cause of the accident scientifically and rigorously,” Xinhua said.

The China Eastern flight was the country’s deadliest aviation disaster in nearly 30 years. Investigators from the US National Transport Safety Board are helping the CAAC to download information from the cockpit voice recorder and the flight data recorder at their lab in Washington.

The preliminary report indicated nothing unusual up to the time the aircraft had departed from its normal flight path, said Joe Hattley, a retired aircraft accident investigator at the Australian Transport Safety Bureau.

“The information being recovered from the aircraft cockpit voice recorder and the digital flight data recorder will be essential to understanding the factors leading up to this tragic accident,” he said.

Air accident specialists have said investigations into accidents as complex as the China Eastern crash could take one or two years to complete.