Hello,
will gorrila glue be good for fixing a crack in a fiberglass fuselage? Thanks for your reply

No, snap the pieces back into place and use thin CA. If you have some fiberglass cloth, cut a piece to cover the area on the inside. You can lay it in place and then use thin CA to bond it to the fiberglass. Or you can use some thinned epoxy. If it is small, the thin CA is the fastest and will strongly fix the crack. When applying the thin CA to the cloth, it takes quite a bit. So make sure that you stand back and not breathe any in. It may also smoke as it cures. Do not touch while curing, or you could end up with a chemical burn.

Thanks