make it airworthy for EASA
As it falls under the category of "historic aircraft" (at that time "Annex II"), it would have been german LBA, not EASA to deal with it. Just like D-AQUI, which is
not under EASA responsibility.
The exact problem was the plan to make it airworthy for "commercial air transport", which is much more complex than having an
experimental certification.
Another issue of course was the actual condition of the airframe, which was significantly worse than expected after the first view.