Hat tip for mentioning "gearing technology". The Pratt & Whitney PW1000G engine is just wild to me. It is a huge leap forward (no pun intended, as CFM's latest is called LEAP). Like all major redesigns, there will be years of bugs and minor failures to work through. Fortunately, they are starting much earlier than all the competition.

EDIT (wiki links)

https://en.wikipedia.org/wiki/Pratt_%26_Whitney_PW1000G

https://en.wikipedia.org/wiki/Geared_turbofan