S
I sincerely hope that the aircraft was on maintenance ................ I don't see the TCH permitting such a modification!!
But there's a story about the lower fin (of course there is!). The A109 was designed by Ing Lovera and the late Ing Bellavita. The latter was the aerodynamicist; I met him on occasion at Cascina Costa, and I was very impressed - a gentleman, and extremely well-read in his discipline. I think it was he who insisted upon the lower fin being added to the orginal basic design which actually was more like the A109 E and derivatives. You can tell it was an add-on if you look at the structural aspect. The upper fin has both a forward and trailing edge spar and a transition frame to the tailboom. The lower fin, as an assembly, is just bolted on with a formed L-shaped fabrication and either 8 or 12 AN3 bolts into anchor nuts. (I forget just how many, but it is completely at odds with the careful integrated design of the rest of the airframe).
Bellavita went to the big bar in the sky some years ago; I see the hand of Lovera in the later A109 marques though.............
.
You are (physically) closer so could confirm the above, but I think it was that way. ~VFR