> Aircraft undergo regular preventative maintenance checks And in a similar incident in February 2018 on a 777 (referred to upthread), one of those checks was

> Aircraft undergo regular preventative maintenance checks And in a similar incident in February 2018 on a 777 (referred to upthread), one of those checks was found to have failed: the NTSB determined that the root cause was a cracked engine fan blade that should have been detected on a previous inspection (and that would have resulted in the blade being replaced), but wasn't. If this incident turns out to have a similar root cause, that means there are issues with the preventive inspection and maintenance process.