An aircraft structural assembly comprising: a composite structure having a first surface with a first mating surface, a second surface with a second mating surface, and a hole ; and a fastener system for the composite structure providing electromagnetic energy protection comprising: a fastener having a head with an engagement surface and a shank received in the hole and having a threaded end; a nut received on the threaded end of the fastener, said nut having an engagement surface ; wherein the nut engagement surface incorporates a reduced area portion engaging the second mating surface of the second surface , wherein the aircraft structural assembly further comprises a washer having an engagement surface and a first mating surface for engaging the engagement surface of the fastener head, wherein the washer engagement surface incorporates a reduced area portion engaging a third mating surface, wherein the aircraft structural assembly further comprises a sleeve receiving the fastener and having a flange and wherein the third mating surface is on the flange. a composite structure having a first surface with a first mating surface, a second surface with a second mating surface, and a hole ; and a fastener system for the composite structure providing electromagnetic energy protection comprising: a fastener having a head with an engagement surface and a shank received in the hole and having a threaded end; a nut received on the threaded end of the fastener, said nut having an engagement surface ; wherein the nut engagement surface incorporates a reduced area portion engaging the second mating surface of the second surface , wherein the aircraft structural assembly further comprises a washer having an engagement surface and a first mating surface for engaging the engagement surface of the fastener head, wherein the washer engagement surface incorporates a reduced area portion engaging a third mating surface, wherein the aircraft structural assembly further comprises a sleeve receiving the fastener and having a flange and wherein the third mating surface is on the flange. a fastener having a head with an engagement surface and a shank received in the hole and having a threaded end; a nut received on the threaded end of the fastener, said nut having an engagement surface ; wherein the nut engagement surface incorporates a reduced area portion engaging the second mating surface of the second surface , wherein the aircraft structural assembly further comprises a washer having an engagement surface and a first mating surface for engaging the engagement surface of the fastener head, wherein the washer engagement surface incorporates a reduced area portion engaging a third mating surface, wherein the aircraft structural assembly further comprises a sleeve receiving the fastener and having a flange and wherein the third mating surface is on the flange. wherein the nut engagement surface incorporates a reduced area portion engaging the second mating surface of the second surface , wherein the aircraft structural assembly further comprises a washer having an engagement surface and a first mating surface for engaging the engagement surface of the fastener head, wherein the washer engagement surface incorporates a reduced area portion engaging a third mating surface, wherein the aircraft structural assembly further comprises a sleeve receiving the fastener and having a flange and wherein the third mating surface is on the flange. <EOS>