N380UA:
Your earlier name calling was totally unfounded, and your request for substantiation of my remarks regarding the mess at Skyguide on that fatal night further reinforces the impression that you are more inclined to shoot from the hip than to entertain an intellectual discourse. Given the fact that 60% of all causes involved in the Ueberlingen mid-air are laid at Skyguide's doorstep, there is no need to deride other countries' ATC.
Anyway: here is the link to the letter from UVEK/BAZL:
http://www.bfu.admin.ch/de/pdf/ueber...llungnahme.pdf
You will also note that the original report by the German BFU listed two "immediate" causes (one being the much belated realisation by Zurich ATC that there was insufficient vertical separation), and three "systemic" causes (of which two were attributed to Skyguide). Skyguide only requested a change in the wording of the two "systemic" causes.
If you care to read the full report, you will note that Skyguide on that night had, in effect, a SMOP - but this was by themselves certified for daytime operations only. They had also not actively instructed their controllers that due to maintenance word (fall back mode) their STAC was inoperative - something P.N. had not been aware of.