Indonesian authorities are a step closer to discovering the cause of the deadly Lion Air crash after one of the airliner’s black boxes was recovered from the Java Sea.

Investigators have begun examining a damaged black box retrieved from the sunken wreckage of the Boeing Co 737 MAX jet that crashed off Jakarta this week, killing all 189 people on board.

The cockpit voice recorder (CVR), which records communications and conversations from the cockpit, is yet to be found, but is believed to be located on the seabed, some 35 meters deep.

The investigation into the first ever crash of the Boeing Co 737 MAX, introduced into commercial service last year, will also be scrutinised by the global aviation industry.

The extent of damage to the device showed the “extraordinary impact” of the crash, Mr Satmiko said.

Searchers have yet to detect a location signal from the second of the two black boxes, housed at opposite ends of the aircraft.

Although the sea floor is relatively shallow, strong currents and energy pipelines in the area have hampered search efforts.

The plane, which had only been in service since August, went silent 13 minutes after taking off on Monday from Jakarta, heading for the tin-mining town of Pangkal Pinang.

The pilot had already received permission to return to base.

A navy diver on board a search vessel told the broadcaster Metro TV that his team found the orange cylinder containing the recorder among debris on the muddy sea floor.

The results from a preliminary investigation into the flight data recorder is expected be made public after 30 days.

Hopes are fading of finding a large section of fuselage intact, with easily retrievable bodies inside.

“What is important for us is to get more information about the victims because having their remains back is important for us so we can bury them properly,” said Ade Inyo, whose brother-in-law was on the flight.

Only one of the flight’s passengers has been identified from the partial remains retrieved so far.

The crash investigation will be carried out with help from Boeing, General Electric and the US Federal Aviation Administration, officials have said.

It will also focus on four Lion Air staff, including its technical director, who the transport ministry said it has suspended on Wednesday, amid speculation that the aircraft had not been airworthy.

Lion Air said the aircraft that crashed had been airworthy and the pilot and co-pilot had 11,000 hours of flying time between them.

But according to the transport safety committee, the plane had technical problems on its previous flight on Sunday, from the resort island of Bali, including an issue concerning “unreliable airspeed”.

-with AAP