As the final moments of the China Eastern Airlines flight crash continue to baffle experts, Chinese authorities are working to decode the contents of black boxes.

The US National Transportation Safety Board (NTSB) said that their team has been tasked with downloading cockpit voice recorder data recovered from the crash site.

“NTSB investigators are assisting the Civil Aviation Administration of China with the download of the cockpit voice recorder from China Eastern Flight 5735 in our lab in Washington,” an NTSB representative said in a statement on Friday.

Also Read | What’s next in China Eastern plane crash investigation?

The move comes almost two weeks after Flight MU5735 crashed into a forested hillside, causing a massive fire. All 132 people on board the Boeing 737-800 were declared dead.

The plane plunged out of the sky at close to the speed of sound before slamming into the mountain. The impact of the plane created a 65-foot-deep pit at the crash site and scattered debris along the side of the mountain.

The cockpit voice recorder, which captures conversations between pilots and other audio clues from within the cockpit, was recovered two days after the crash. A second “black box” that captures flight data, including pilot inputs and plane performance, was found last Sunday.

The exteriors of both the black boxes are severely damaged, but the data within seems to be retrievable. 

Also Read | China plane crash: Second black box unearthed from buried wreckage

It can take days or even weeks to analyse data recovered from the black boxes of crashed aircraft. 

The plane was cruising at 29,000 feet when it suddenly nose-dived. Air traffic control attempted to contact the pilots several times after noticing the plane’s drop in altitude, but received no answer.

The Civil Aviation Administration of China said an NTSB team, comprising seven experts, arrived in China on Saturday.

“Investigators will limit interactions with those outside of [the] investigation similar to safety protocols at Beijing Olympics, which will allow them to begin work immediately without a quarantine,” the NTSB posted on Twitter.

Chinese aviation officials said Thursday that a core area surpassing 400,000 square meters was searched by teams. More than 49,000 pieces of aircraft wreckage were found from the site. The wreckage was being cleaned up and will be analyzed by forensics.

Also Read | China Eastern Flight MU5735: All 132 declared dead as mystery continues

The remains of the victims found at the site were now at the Wuzhou funeral parlor for proper custody. The remains were being identified. The authorities have not released the passenger manifest, yet.