The Indonesian jet that crashed shortly after takeoff had equipment problems Technical Protocol from the BBC the day before
A technical record of a flight from Bali to Jakarta on Sunday said an instrument was "unreliable" and the pilot had to surrender to the first officer.
The Boeing 737 plane crashed into the sea with 1
It went down after the start from Jakarta. There are no signs of survivors.
The BBC has not been able to comment on Lion Air, the low-cost carrier that owns the aircraft.
The JT 610 flight led to the western city of Pangkal Pinang. Rescuers have recovered some body and personal items, including baby shoes. The families are ordered to go to a hospital to identify the dead.
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The incident is said to have been the first major accident Boeing 737 Max – an updated version of the 737.
What was the instrument problem?
A technical protocol that the BBC received from the last flight of the aircraft suggests that the captain's airspeed was unreliable and the altitude readings varied on the captain's and first officer's instruments.
"Identifies that CAPT [captain’s] instrument was unreliable and transfer control to FO [first officer]," reads the minutes. "NNCs from Airspeed Unreliable and ALT disagree."
The crew decided to continue their flight and land safely in Jakarta.
The former Lions Air boss, Edward Sirait, said the aircraft had an unspecified "technical problem" when it had flown from Denpasar in Bali to Jakarta that had been "disbanded".
"If the plane had been broken, it would have been impossible to clear the plane to fly from Denpasar," he said. "When we received the flight crew report, we immediately resolved the problem."
The airline operates 11 Boeing 737 Max 8 aircraft, but the others had no similar technical problem and there is no plan to ground the fleet, he added
What happened to the plane?
JT 610 flight departed Jakarta on Monday at 06:20 (Sunday, 23:30 GMT).
An hour later, she was due to arrive at Depati Amir Airport in Pangkal Pinang, but 13 minutes after the flight, the authorities lost contact.
The pilot had requested official information to return to Jakarta Soekarno-Hatta Airport.
Sutopo Purwo Nugroho, head of the Indonesian Disaster Bureau, tweeted images of rubble and personal belongings that came from the plane and found floating in the sea.
What do we know about those on board?
Lion Air said in a statement that the pilot and co-pilot had more than 11,000 flying hours between them.
Three of the crew aboard were flight apprentices
Twenty employees of the Indonesian Ministry of Finance were also on board, the BBC has learned.
A spokesman for the ministry said they worked in the offices of the Ministry of Finance in Pangkal Pinang but were in Jakarta over the weekend.
What? Do we know this plane?
The 737 Max Series is the fastest-selling aircraft in Boeing history and has four models – Max 7, Max 8, Max 9 and Max 10.
The Boeing 737 Max 8 has been in commercial use since 2016 ,
The aircraft involved in the crash was built in 2018. It is a single-track aircraft used for short-haul flights.
In a statement, Boeing expressed sympathy for the victims from families and said it was "ready to provide technical assistance with the accident investigation."
Australia told government officials and contractors to stop using the airline until the results of the investigation were known.
What is Indonesia's aviation safety record?
Indonesia, a vast archipelago, is heavily dependent on air travel, but many of its airlines have a poor safety record.
Lion Air was founded in 1999 and operates both domestic and international flights to Southeast Asia, Australia and the Middle East.
There have been problems in the past with regard to security and poor airspace management by 2016.
In 2013, the Lion Air Flight 904 crashed when landing at Bali's International Airport into the sea. All 108 people on board survived. In 2004, Jakarta Flight 538 crashed on landing in Solo City, killing 25 people.
In 2011 and 2012, a number of pilots owned by methamphetamines were found in an incident hours before a flight
Additional coverage by Stephen Fottrell