Indonesian investigators said the cockpit recording from the crashed Lion Air jet showed the pilots searching a manual to try to find why the plane kept lurching downwards.
The details were revealed at a press conference, where an investigator said the recording captured a "panic" in the cockpit in the last 20 seconds of the flight.
They are looking into how a computer ordered the plane to dive in response to data from a faulty sensor and whether the pilots had enough training to respond to the emergency.
The investigation has taken on new urgency after a second 737 MAX 8 crash at Ethiopian Airlines last week killed 157 people and led to the global grounding of the model.

Building collapse in Brooklyn kills at least 2, injures more than 10
Israeli strike on southern Gaza hospital kills six
Saudi Arabia says debris from intercepted Houthi missiles falls in Mecca region
Climate crisis is 'outrunning us', UN chief warns COP31
