The Sriwijaya Air plane that crashed last month killing 62 people had an imbalance in engine thrust that eventually led the plane into a sharp roll and then a final dive into the sea, a preliminary report by investigators said on Wednesday.

When the 26-year-old Boeing Co 737-500 plane reached 8,150 feet (2,484 m) after take-off, the left engine throttle lever moved back while the right lever stayed in its original position, Indonesia's National Transportation Safety Committee (KNKT) said in its report.