Grounding and Bonding in Aircraft

STATIC DISCHARGE WICKS Static wicks are considered a part of the “bonding” system on an aircraft rather than the “grounding” system. The bonding system in an aircraft is designed to ensure electrical continuity between various metallic components, such as the airframe, wings, control surfaces, and other conductive parts. It helps to equalize the electrical potentials between these components, reducing the risk of static discharge and promoting safe electrical operation. When the aircraft is in flight, static wicks help to dissipate or discharge static electricity by providing a point of ionization. The ionized air around the wick helps to minimize the potential for disruptive or uncontrolled discharges. This discharge path prevents the buildup of excessive static charge and reduces the potential for electrical interference with aircraft communication systems.

Static wicks consist of conduc- tive materials, such as metal or carbon fibers, that provide a controlled path for static charges to dissipate into the surrounding air. By regularly discharging the static electric- ity, the wicks both help reduce the likelihood of a lightning strike as well as mitigate the buildup of potentially damag- ing electrical charges on the aircraft’s surfaces. In the event of a lightning strike, static wicks pull double-duty as the lightning discharge point, returning the surge current back into the atmosphere. Composite structures, common- ly used in modern aircraft, and in the emerging eVTOL indus- try, pose unique challenges for grounding and bonding due to their inherently poor conductiv- ity. During the manufacturing process of composite struc- tures, provisions must be made for lightning strike dissipa- tion and equipment bonding. Composite Structures:

Typically this involves incorpo- rating metallic foils, meshes, or embedded conductive paths within the composite material layers to reproduce the Faraday cage behavior of an aluminum fuselage. In addition, conduc- tive elements, such as bonding straps or wires, are used to create electrical continuity between different produc- tion breaks (if any) within the composite structure. Finally, composite aircraft incorporate metallic attachment points, such as brackets or threaded inserts, for the mounting and grounding of equipment. The electrical bonding via metal- lic attachments to the aircraft’s Electrical Structure Network establishes electrical continu- ity and minimizes potential differences between conduc- tive composite elements and metallic components. Conductive elements within the composite structure—again, sub-surface foils and conduc- tive strips—provide a pathway for electrical currents to flow and establish equipotentiality.

Static Wicks Static wicks, also known as static discharge wicks or static dischargers, are devices installed on the trailing edges of aircraft surfaces, such as wings, vertical stabilizers, or antennas. These devices are designed to manage and dissi- pate static electricity buildup that occurs naturally on wings and other external surface in order to minimize the risk of a larger electrical discharge.

Lightning diverter strips on the nose of an airplane

QwikConnect • July 2023


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