...and never found the hook.
Did you try using the HOOK lever in the cockpit? Right side vertical panel, above the Cautions/Warnings panel? Hard to miss. Has a rectangular, red light above it to indicate it's down.
If it lowers the hook, go into you key assignments menu, and see if anything has changed it. Another add-on plane, an add-on gauge, or whatever, that you may not have noticed. Same for FSUIPC. If you have the payware version it can have this effect. Won't show in your key assignments menu, but it is in the FSUIPC information.
I don't have P3D, nor the payware version of FSUIPC, so I can't be more specific. Sorry about that.
Also, make sure you don't have any add-on program running alongside P3D that could capture that key assignment. A screen-cap program, a FBW add-on program, auto-trim, etc etc. Worth taking a look, anyway.
Hope something in all my babbling helps a little...
Pat☺