Indonesia's National Transportation Safety Committee believes that the Lion Air Boeing 737 Max 8 which crashed on 29 October had been operating with a faulty airspeed indicator for its last four flights.
Speaking at a 5 November press conference, NTSC chief Soerjanto Tjahjono said the agency had found signs that the airspeed indicator was faulty after downloading information from the jet's flight data recorder.
The NTSC is reviewing the aircraft's maintenance records and interviewing maintenance personnel.
Tjahjono stresses that the yet-to-be-recovered cockpit voice recorder is critical to the investigation.
Local media have reported that the emergency locator transmitter has been found. A crash-survivable memory unit from the flight data recorder had been recovered on 1 November, and a landing gear and its components on 2-3 November.
Indonesian navy official Guntur Pramudanto has told the media that plans to lift the jet's fuselage from the seabed using an air lifting bag failed.
"We believe that the fuselage is now in a fragile condition," says Pramudanto.
Indonesia's national search and rescue agency Basarnas is meanwhile exploring the possibility of extending its efforts beyond 7 November.
Basarnas chief Muhammad Syaugi believes that the CVR is buried in the muddy seabed, and says ping signals emitting from the recorder are starting to weaken.
The jet, registered PK-LQP, was operating flight JT610 from Jakarta's Soekarno-Hatta International airport to Pangkal Pinang when it crashed into the sea near the town of Karawang. There were 189 on board.