1. Don’t see the broken fin (I do see some bent fins)
2. That is the FRONT of the engine? How does that blow up at 600+ miles per hour from something inside?
I dug into this a little bit more. Mechanical things of all types fascinate me.
The missing fan blade is at the 8~8:30 position, and there is some damage distortion to a few others.
This damage is strikingly similar to another incident in 2016 to the same engine type where the front cowling is completely torn off.
Testing procedures include blowing off one fan blade. This is to validate the design requirements that the blade is to be contained within the nacelle, and also to validate the engine fan’s ability (along with the entire engine assembly) to withstand the resultant out-of-balance condition.
Conjecture on a video I saw proposed the resultant vibration tore off the front cowling. While test videos I’ve seen demonstrate no cowling tear-off, I don’t know if the simulated testing damage also was done in a wind tunnel.
Heavy vibration + air speed forces may have coupled together to do this.