[bonesmccoy]

That's a tile piece from the underside of the wing.

You can tell because the corner of the tile is chipped and you can see the silica under the chipped surface.

[hole_n_one]

[Ichneumon]

That's a tile piece from the underside of the wing.

I agree it's probably a tile, but there's no way you can tell if it's "from the underside of the wing" -- such tiles are used on the nose, under the fuselage, and other places as well.