There are big heavy disks that hold the blades in place. The section that blew apart here is the bypass fan...those are the big blades you see at the front of the engine. There are a lot of root causes for fan, compressor and turbine disks to fail. Usually a single blade let’s go, often taking out other blades, but the whole fan disk doesn’t disintegrate. Seems like there have been two or three fan disk failures per year the last few years. This looks like catastrophic failure of the fan disk as the entire fan is gone. What is remarkable is that the ruptured fandango doesn’t cascade backward through the compressor and turbine.
Excellent input. Thank you.