A preliminary report into last month's Lion Air plane crash into the sea off Bali urges the budget carrier to immediately address safety concerns by providing training for pilots during critical landing times.

The National Transportation Safety Committee's investigation did not outline what caused the accident, but said the brand new Boeing 737-800 aircraft was airworthy. It issued three safety recommendations for Lion Air to ensure its pilots are properly trained regarding handing over the controls at critical altitudes and times, and how to respond when visibility is limited at minimum altitudes.

The report says the 24-year-old co-pilot called out that he could not see the runway twice before the pilot took over the controls at an altitude of 150 feet (45 meters) just before the crash.