I used them on the side access doors on my MB-339.

These doors are always closed during flight so there are not really any loads on them, but I would guess that the hinges would probably be ok for gear doors as long as you got a really good glue joint between the hinge and the gear door. I roughed up the metal hinge with a dremel coarse sanding drum (until all of the brass finish had been removed), then glued to the the fiberglass with Hysol 9462. You just have to be very careful not to get any glue into the hinge itself.