I have done a quick and rough translation of the German article into English. Hopefully this is better than the Google Translate version: https://gist.github.com/alexcoplan/0018e3320f99a612c737
I still don't understand "The crash is the worst accident since the development of the A400M", though. To me that implies there was a pretty devastating accident during the development.
I think it's sloppy journalist writing for the worst accident that happened with the development of the A400M.