The invention is a joint cover assembly for covering a gap adjacent an edge of a panel that covers a sub-surface, and a method of covering such a gap. The first porthole member is a rigid plate having a front side, a back side, an opening disposed therethrough, and further having a tubular portion aligned with the opening and extending from the back side. In one aspect, the unmanned apparatus includes a clamping mechanism coupled to the structural member, wherein the clamping mechanism is capable of detachably attaching the unmanned apparatus to the elongated structure. The semiconductor layer and a dielectric oxide layer underneath are etched selective to the remaining portions of the dielectric nitride. The inertial sensor mass has a greater density than the elastomeric material.