Abstract: A method for determining an object of a test for verifying the lightning protection adequacy of a fastening part includes: a structural pattern population generating step of generating a population of structural patterns identified by a combination of a plurality of properties of the fastening part; a section extracting step of extracting those sections which are disposed in a wet area of the aircraft where fuel or fuel vapor is present, from the sections of a fastening member, for each of the structural patterns of the population; a group setting step of setting a group of structural patterns of the same predetermined properties for each of the sections; and a representative pattern selecting step of selecting a representative pattern representative of the group from the structural patterns belonging to the same group. The structural pattern narrowed down through the steps is determined as the test object.

Abstract: In an insulating cover 50A according to the present invention, a dimension of each of an outer-circumferential-side cylindrical part 50c and an inner-circumferential-side cylindrical part 50b fitting in step parts 40 and 41 in an axial direction of a fastener body 25 is set large with respect to a tip covering part 50a covering a tip surface 26a of a fastening member 26. As a result, on an outer circumferential side and an inner circumferential side of the fastening member 26, a distance from a member 22 is sufficiently ensured by the cylindrical part 50b and 50c. The tip covering part 50a is thinner than the cylindrical part 50B and 50c. Therefore, when the fastener body 25 and the fastening member 26 are fastened together, the amount of deformation of the tip covering part 50a in a thickness direction can be made small.

Abstract: A cap (9) that is used in a fixing structure (1) for fixing a plurality of overlaid structural members (3) by means of a fastener (5) inserted into through-holes (3a) formed in the overlaid structural members and a collar (7) fastened onto a distal end (5a) of the fastener protruding from a surface of the structural members and that is disposed so as to surround the distal end of the fastener and the collar. The cap is attached, in a non-engaged state, to the distal end of the fastener and the collar, and a concave groove (9d) that accommodates a sealant (11) to be filled in a space formed between an inner peripheral surface (9e) and the surface of the structural members is formed in the inner peripheral surface.

Abstract: In an insulating cover 50A according to the present invention, a dimension of each of an outer-circumferential-side cylindrical part 50c and an inner-circumferential-side cylindrical part 50b fitting in step parts 40 and 41 in an axial direction of a fastener body 25 is set large with respect to a tip covering part 50a covering a tip surface 26a of a fastening member 26. As a result, on an outer circumferential side and an inner circumferential side of the fastening member 26, a distance from a member 22 is sufficiently ensured by the cylindrical part 50b and 50c. The tip covering part 50a is thinner than the cylindrical part 50B and 50c. Therefore, when the fastener body 25 and the fastening member 26 are fastened together, the amount of deformation of the tip covering part 50a in a thickness direction can be made small.