SINGAPORE/JAKARTA (Reuters) Indonesian investigators will deliver their first report into the Lion Air crash on Wednesday, a month after the brand-new Boeing 737 crashed into the sea, killing all 189 on board in the countrys second-worst air disaster.

The report, which comes as the search continues in the Java Sea for the jets cockpit voice recorder, is not expected to draw firm conclusions from the ongoing investigation into the Oct. 29 crash.

However, investigators have said they are focusing their attention on the Boeing 737s anti-stall system.

The doomed jets systems had detected it was in a stall due to a faulty indicator and gave the captain a warning through a stick shaker that vibrated the controls, Nurcahyo Utomo, an investigator at Indonesias transport safety committee (KNKT), told parliament last week.

The Maneuvering Characteristics Augmentation System (MCAS) an automated modification new to the model that crashed activated and directed the jets nose down to prevent a stall, Utomo said.

The pilots counteracted that successfully for some time before the plane entered a final dive, he added.

The same anti-stall system had activated on the jet during a flight the previous evening, but the pilots in that case managed to shut off the system, Utomo said.