JAKARTA, Indonesia (AP) — A malfunctioning automatic throttle may have caused the pilots of a Sriwijaya Air jet to lose control, leading to the plane's plunge into the Java Sea last month, Indonesian investigators said Wednesday.

National Transportation Safety Committee investigators said they are still struggling to understand why the jet nosedived into the water minutes after taking off from Jakarta on Jan. 9, killing all 62 people on board.

The investigators issued a preliminary report that provided new details of the pilots’ struggle to fly the plane from almost as soon as it became airborne.

The lead investigator, Nurcahyo Utomo, said the left engine throttle lever had reduced its power output just before the jet plunged into the sea.

He said pilots of previous flights had reported problems with the automatic throttle system on the 26-year-old jet.