Danang Mandala Prihantoro, a Lion Air official, said in a statement that the aircraft had been in service only since August. âLion Air is very concerned about this incident and will collaborate with relevant agencies and all parties,â Mr. Danang said. The airline, he said, had set up hotlines for the relatives of passengers to call for information.
The cause of the crash was not clear.
FlightRadar24, a flight tracking service, said that it had analyzed preliminary satellite navigation data from the flight that showed an âincrease in speedâ and âhigh rate of descentâ from the planeâs last transmission.
The data released by FlightRadar24 showed Mondayâs flight taking off and initially ascending to what would be a normal altitude. But within a couple of minutes, the plane suddenly plunged 500 feet and banked left in an unusual flight pattern. The plane then ascended and leveled off before what appears to have been a sharp descent into the Java Sea.
âThe erratic flight path makes us suspect a problem with the pitot-static system,â said Gerry Soejatman, an Indonesian aviation expert, referring to the instruments used to record the flightâs airborne speed and altitude.
Mr. Soejatman said he had looked at the flight data from Sundayâs flight and noted a âsimilar erratic climb and groundspeed problem,â leading him to suspect a problem with the instruments had also been an issue then.
Several plane crashes have been blamed on blockages or other problems with pitot tubes, a probe on the outside of the aircraft, which resulted in erroneous speed or altitude readings, Mr. Soejatman said.
Conchita Caroline, a television presenter who was on Sundayâs flight from Bali to Jakarta, said the beginning of the journey was marred by irregularities. As the plane readied for takeoff, the engine seemed to die several times, she said.
For about half an hour, the passengers were kept on the plane at the Bali airport with no explanation, even as a lack of electricity made the interior hot and stuffy, she said, causing children to cry and some older passengers to vomit.
âThe passengers were all confused,â Ms. Caroline said. âWe had no idea what was going on.â
The plane eventually took off, but Ms. Caroline said that the air conditioner did not work well during the flight and that the floor under her feet felt hot to the touch. The right engine, which she could see from her window, was shaking, she said.