An Indonesian passenger jet's throttles showed an "anomaly" and had been repaired several times before a deadly accident last month, but the exact cause of the crash was unclear, investigators said on Wednesday.
"The left (engine throttle) was moving backward too far while the right one was not moving at all - it was stuck," said National Transportation Safety Committee investigator Nurcahyo Utomo.
The agency on Wednesday released its preliminary report on the crash that killed all 62 passengers and crew.
"But what would have caused this anomaly? We can't conclude anything just yet."