(Recasts, adds detail on black box investigation)
JAKARTA, Nov 1 (Reuters) - Indonesian authorities said they would immediately begin examining a damaged black box retrieved on Thursday from the sunken wreckage of a Lion Air jet that crashed off Jakarta this week, killing all 189 people on board.
Indonesia's second-deadliest air disaster since 1997 has prompted renewed concern about its patchy safety record, and the government has said Lion Air will be regulated more closely.
The investigation of the first crash of a Boeing Co 737 MAX, introduced into commercial service last year, will also be scrutinised by the global aviation industry.
"Tonight we will move as quickly as possible to download what is in this black box," Haryo Satmiko, deputy chief of Indonesia's transportation safety committee (KNKT), told a news conference.
The extent of damage to the device showed the "extraordinary impact" of the crash, he said.
Despite initial reports, authorities did not know for certain whether the "crash survivable memory unit" was from the flight data recorder or cockpit voice recorder, as portions of it were missing, 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 seafloor is only about 30 metres down, strong currents and energy pipelines in the area have hampered search efforts.
The data it holds should provide clues to what went wrong.
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.
Under normal conditions, the data should only take two hours to download, said Satmiko, although analysing it could take several weeks.
The results from a preliminary investigation will be made public after 30 days, another KNKT official said.
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 investigation will be carried out with help from Boeing, General Electric and the U.S. 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 aircraft had not been airworthy.
The privately owned budget carrier was founded in 1999. Its aircraft have been involved in at least 15 safety incidents and it has been placed under tougher international safety restrictions than other Indonesian airlines.
It will now be subjected to more intensive "on ramp" inspections than other airlines, authorities said.
President Joko Widodo has also ordered a review of all regulations relating to flight safety.
Indonesia is one of the world's fastest-growing aviation markets. Its transport safety committee investigated 137 serious aviation incidents from 2012 to 2017.
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".
Lion Air chief executive Edward Sirait has acknowledged reports of technical problems with the aircraft, but said maintenance had been carried out "according to procedure" before it was cleared to fly again.
Lion Air's only other fatal accident was in 2004, when an MD-82 crashed upon landing at Solo City, killing 25 of the 163 people on board, according to the Flight Safety Foundation's Aviation Safety Network.
In April, the airline announced a firm order to buy 50 Boeing 737 MAX 10 jets, with a list price of $6.24 billion. It is one of the U.S. planemaker's largest customers, and was the first carrier anywhere to take delivery of the narrow-body jet.
(Reporting by Jakarta bureau; Writing by Fergus Jensen and Ed Davies; Editing by Kevin Liffey)