Seal system for removable cover

A structure having a pair of components, releasably secured to one another by fasteners, said fasteners including a plurality of studs secured to one of said components and passing through holes in another of said components with a spacing between a radially inner surface of said hole and a radially outer surface of said stud to define an annular void between each hole and a respective one of said studs, and a nut having a blind bore extending from an end face and threaded to receive said stud, said structure further including a seal assembly to provide a seal between said components, said seal assembly comprising a first resilient seal extending between and located on said studs to be interposed between said components, a non-conductive bushing on each of said studs and located in respective ones of said annular voids, each of said bushings having a radial flange to overlie a periphery of said hole, a pair of resilient gaskets located on opposite sides of each of said radial flanges, a rigid washer located on a respective one of said studs and overlying one of said pair of resilient gaskets, a further resilient gasket located on an opposite side of said rigid washer to said one of said pair of resilient gaskets to sandwich said rigid washer between one of said pair of resilient gaskets and said further resilient gasket, and an O-ring located on said stud between an end face of said nut and said further resilient gasket to effect a seal therebetween, whereby, upon tightening of said nut on said stud, said gaskets are compressed to provide a seal between adjacent surfaces and said bushing maintains said stud spaced from said holes.