I command thee to come out of the rock under which thou hast hid thyself, and behold the light, for, unpatchable though the Asobo Longitude might seem, yet hath one of us, Dakfly0219, a true son of his father, found a way around that (without breaking any rules), and has even updated it to the latest UK up(down)date 
, and those of us who witnessed him solve this puzzle, are so overjoyed that we have vowed within ourselves to never touch the stock Longitude ever again. No, not even with a 20-foot pole. For it does not come close in any way whatsoever to the mod that Dakfly0219 has created. This mod works perfectly with the Working Title Garmin G3000/5000 mod.
Behold some of my most cherished images that I took myself:
Get those two mods, and you will never touch any other aircraft (saving, maybe other modded ones like the A3NX, TBM, etc, of course).
For the Working Title G3000 (in case you don’t know of it):
or: