Umberto. There was another thread on this forum about fog around the tires that you haven't answered yet even though you said you would. It was the one that had a jpg of a Caravan.
It's not true "I haven't answered", it's just this question has been made many times, and I always answered that's who the scenery is made. It's a scenery that was made for FS9, updated for free to be used in FSX, and again updated for free to be used to P3D, including ensuring compatibility for P3D5 to make it usable, again all for free, including a recent free update to replace default jetways with SODE jetways.
But you cannot just expect perfect compatibility from a 10+ years old scenery originally made for FS9 in P3D 5.1, it's just not possible, without doing an almost complete makeover, which is planned.