Aircraft fuel tank with an electrical bond separate from a fuel tank fastener
A aircraft fuel tank includes an inner layer having an inner surface and an outer surface; an outer layer having an inner surface and an outer surface, the inner surface of the outer layer and the outer surface of the inner layer aligning at an interface; a fastener extending through the inner layer and the outer layer to hold the inner layer and the outer layer together; and an electrical bond separate from the fastener and conductively coupling the inner layer and the outer layer together; the electrical bond is to provide a pathway for an electrical current to travel separate from the fastener.
1 . An aircraft fuel tank, comprising:
an inner layer having an inner surface and an outer surface;
an outer layer having an inner surface and an outer surface, the inner surface of the outer layer and the outer surface of the inner layer aligning at an interface;
a fastener extending through the inner layer and the outer layer to hold the inner layer and the outer layer together; and
an electrical bond separate from the fastener and adjacent to the fastener, the electrical bond conductively coupling the inner layer and the outer layer together, the electrical bond being selected from a group consisting of: (1) a spot face electrical bond at least partially surrounding a stem of the fastener; and (2) a washer positioned around the stem of the fastener;
wherein the electrical bond is configured to provide a pathway for an appreciable amount of electrical current to travel separate from the fastener.
2 . The aircraft fuel tank of claim 1 , wherein the electrical bond is extends outwardly from the stem.
3 . The aircraft fuel tank of claim 2 , wherein the electrical bond surrounds the stem of the fastener.
4 . The aircraft fuel tank of claim 1 , wherein the electrical bond extends through the interface between the inner layer and the outer layer.
5 . The aircraft fuel tank of claim 1 , wherein, when the electrical bond is the spot face electrical bond, the spot face electrical bond is a direct connection between the inner layer and the outer layer in a portion of the interface that lacks a primer such that the inner layer and the outer layer come into direct contact when force is applied via the fastener.
6 . The aircraft fuel tank of claim 1 , wherein, when the electrical bond is the washer, the washer is a metal ring separate the inner layer and the outer layer, the washer coming into contact with each of the inner layer and the outer layer once force is applied via the fastener to create the pathway between the outer layer and the inner layer.
7 . The aircraft fuel tank of claim 1 , further comprising a primer positioned along the outer surface of the inner layer and along the inner surface of the outer layer.
8 . The aircraft fuel tank of claim 7 , wherein the primer extends within the interface up to the electrical bond.
9 . A method of diverting current away from a fastener in a aircraft fuel tank, the method comprising:
selecting an inner layer, an outer layer, and a fastener for the aircraft fuel tank;
connecting the inner layer and the outer layer with the fastener, the fastener extending from an outer surface of the outer layer to an inner surface of the inner layer;
creating an electrical bond between the inner layer and the outer layer that is separate from the fastener and adjacent to the fastener such that the inner layer and the outer layer are conductively coupled, the electrical bond being selected from a group consisting of: (1) a spot face electrical bond at least partially surrounding a stem of the fastener; and (2) a washer positioned around the stem of the fastener;
exposing the aircraft fuel tank to an electrical current;
wherein the electrical bond provides a pathway for the electrical current to travel that is separate from the fastener, thereby diverting at least a portion of the electrical current away from the fastener.
10 . The method of claim 9 , wherein the electrical bond extends outwardly from the stem.
11 . The method of claim 9 , wherein creating the electrical bond further comprises surrounding the stem of the fastener with the electrical bond.
12 . The method of claim 9 , wherein the electrical bond extends through an interface between the inner surface of the outer layer and the outer surface of the inner layer.
13 . The method of claim 9 , wherein, when the electrical bond is the spot face electrical bond, the spot face electrical bond is a direct connection between the inner layer and the outer layer in a portion of the interface that lacks a primer such that the inner layer and the outer layer come into direct contact when force is applied via the fastener.
14 . The method of claim 9 , wherein, when the electrical bond is the washer, the washer is a metal ring separate from the inner layer and the outer layer, the washer coming into contact with each of the inner layer and the outer layer once force is applied via the fastener to create the pathway between the outer layer and the inner layer.
15 . The method of claim 9 , further comprising adding a primer within the interface, the primer extending up to the electrical bond.
16 . The method of claim 9 , wherein at least a portion of the electrical current is a substantial amount of the electrical current.
17 . The method of claim 9 , further comprising determining a diameter and a material of the electrical bond based on a plurality of factors.
18 . The method of claim 17 , wherein the plurality of factors comprises a material of the fastener stem and a thickness of each of the inner layer and the outer layer.
19 . The method of claim 18 , wherein the plurality of factors further comprises a clamping force applied by the fastener and a thickness of a primer within the interface.