Mystery Over China Plane Crash Deepens After Discovery Six Miles From Crash Site

China has since confirmed that all 123 passengers and nine crew members were killed, with a translated tweet from the China News Service earlier today (Saturday 26 March) saying: "After 6 days of full-scale search and rescue, the National Emergency Response Headquarters of the '3.21' China Eastern Airlines MU5735 aircraft flight accident confirmed on the evening of the 26th that all 123 passengers and 9 crew members on China Eastern Airlines flight MU5735 were killed."

Flight data recorded by Flightradar24 appeared to show the aircraft suddenly lose altitude at around 2.22pm local time (6.22am GMT), roughly 40 minutes before it was due to land in Guangzhou.

Now, a piece of debris believed to be from the China Eastern Airlines plane has been discovered six miles away from the crash site, with Chinese officials saying if the piece is confirmed to be part of the Boeing 737-800 that crashed, it could mean the plane may have broken apart mid-air.

Zheng Xi, head of the Guangxi fire-fighting rescue team, said at a briefing that the piece was around 1.3 metres long and 10 centimetres wide.

However, at this stage in the investigation, officials said it is not possible to know if the aircraft piece was loose as a result of the 'stresses' during the fall, or if it came off before the descent.

Jeff Guzzetti, former chief of accident investigations at the US Federal Aviation Administration, said the discovery raised further questions about what happened.

China's first major air tragedy in more than a decade has prompted a review of safety procedures by the government and baffled air crash investigators.

Flight data recovered from the black box recorder is being analysed in Beijing but may take up to a fortnight to be made public, according to Chinese state media.

Earlier this week, Xi told reporters that the first victims had been found, with human remains recovered on Wednesday 23 March.

Investigators have also discovered what they believe to be the cockpit voice recorder in the wreckage - one of two black boxes aboard the plane - with Zhu Tao, director of the Office of Aviation Safety at the Civil Aviation Authority of China, saying it will be sent to Beijing for decoding and analysis.

How long that will take depends on the degree of damage the unit suffered, he explained, adding: "This will provide important evidence as to the cause of the accident."

Mao Yanfeng, an official at the Civil Aviation Administration of China (CAAC), said: "Currently, we cannot determine the exact time needed for the data downloading and analysis of the black box already recovered."