Jakarta: A design flaw, inadequate pilot training and poor flight crew performance contributed to a Boeing jet crashing in Indonesia last year, killing all 189 people on board, investigators said on Friday.

The Lion Air disaster was followed months later by a second crash — involving the same model of aircraft — when an Ethiopian Airlines plane went down with 157 people aboard, leading to the global grounding of Boeing's entire 737 MAX fleet. The crashes had thrown a spotlight on the MAX model's Manoeuvring Characteristics Augmentation System (MCAS), an anti-stall mechanism that pilots in both planes had struggled to control as the jets careered downwards.