No abnormalities yet discovered in MU5735 investigation

China's civil aviation regulator found no abnormalities in the crashed flight MU5735 based on the present facts, according to a preliminary investigation report released by the Civil Aviation Administration of China on Wednesday.

The report includes information on flight history, crew, maintenance and wreckage distribution.

According to the Chicago Convention on International Civil Aviation, an initial report should be completed within 30 days of an accident. The preliminary report usually contains facts currently obtained and does not include analysis of the cause of the accident or conclusions.

Flight MU5735 departed from Kunming, Yunnan province and was scheduled to arrive in Guangzhou, Guangdong province. It crashed on a mountain in Wuzhou, Guangxi Zhuang autonomous region, on March 21, which claimed the lives of all 132 people on board.

According to the investigation, the qualifications of the flight crew, cabin crew and maintenance and release personnel all met requirements. The airworthiness certificate of the aircraft was valid.

The jet's latest A checks and C checks were carried out within maintenance windows.

There was no fault report before the departure of the flight on March 21.

No cargo was declared as dangerous goods on board. No abnormalities were discovered on devices along the routes, including navigation and surveillance equipment.

No dangerous weather was forecasted. Before the jet deviated from cruise altitude, no abnormalities were discovered in the radio communication or control command between the crew and air traffic control. The last normal call between land and crew was made at 2:16 pm.

The two recorders onboard were severely damaged due to the impact, and data restoration and analysis work is underway.

The report also depicted the flight's route before the crash. The jet departed from Kunming at 1:16 pm and reached 8,900 meters at the cruise altitude at 1:27 pm. It entered the air traffic control zone of Guangzhou at 2:17 pm. Radar in Guangzhou received a flight deviation warning at 2:20:55 pm.

The aircraft was then released from cruising altitude. The controller called the crew but received no response. The last radar information recorded for the jet was at 2:21:40 pm — with standard pressure altitude at 3,380 meters, ground speed at 1,010 km/h, heading 117 degrees. The radar signal then disappeared.

The technology team will continue to carry out investigations into the cause of the accident, including in-depth wreckage identification, classification, flight data analysis and experimental verification.

When black boxes are recovered in fairly good condition, investigators can analyze and produce a report on their content within about three months. It requires data retrieval, decoding and analysis before producing a report. But it can take much longer when they are damaged, said Li Xiaojin, a professor from the Civil Aviation University of China in Tianjin.

According to information disclosed by the CAAC, the exterior of the flight recorder was seriously damaged and the storage units also had a certain degree of damage. But the device remained in relatively good shape.

"It takes time to decode the flight recorder. If the storage units were damaged, it may take longer. After decoding the device, it will provide strong evidence as to the cause of the accident," said Zhu Tao, head of aviation safety for the CAAC, at an earlier news conference.