The first black box of China Eastern Airlines' crashed MU5735 passenger jet is under analysis in Beijing, officials said on Thursday. 

"We still cannot rule out the possibility that the storage parts of the black box have broken," an official from the Civil Aviation Administration of China (CAAC) told reporters at a press conference.

The first black box, or the cockpit voice recorder, was found some 20 meters away from the main impact area on Wednesday afternoon and was transferred to Beijing in the evening. Experts are now trying to extract and decrypt the data in the box.

According to an analyst, the process could take anywhere between a few days to as long as half a year.

The black boxes are data storage devices that save critical data of planes for analysis. One box contains voices recorded in the cockpit, while the other provides critical parameters for experts to understand what happened to the plane.

Read more: Experts: What black box can tell you about vertical crash of MU5735

Rescuers are still searching for the other black box around the crash site. They have also found major parts of the destroyed aircraft within a 30-meter radius, the local authority said.

The wreckage could be the engine of the crashed plane, according to a China Media Group reporter.

Pickle fork repair 'unrelated' to crash

Not long after the crash, many people on social media found a report saying China Eastern Airlines repaired a part in Boeing 737-800 model called "pickle fork," which they said may have led to the crash.

But aviation officials said it's not related because the crashed plane was not included in the repair.

"Only one plane from China Eastern Airlines was included, which was retired back in September 2020," said Liu Xiaodong, a manager of the company.

Liu also told media that the company didn't reduce funds for repair after the onset of the pandemic. "Instead, there was a 12-percent increase in spending on repairs in 2021 compared to that of 2019," he said.

Read more: What you need to know about the crashed Boeing 737-800