What is the primary function of bonding in aircraft electrical systems?

What is the primary function of bonding in aircraft electrical systems?

• A. Bonding provides a low-impedance path to equalize potentials between conductive parts.
• B. Grounding establishes a common reference and fault return path, reducing shock risk and improving EMI/Lightning protection.
• C. Bonding and grounding are the same, serving the same function.
• D. Bonding prevents insulation breakdown by shielding circuits.

Answer: (A)

Bonding is about making all conductive parts that could come into contact or influence each other sit at the same electrical potential. By tying metal surfaces—airframe sections, fuel tanks, panels, and equipment grounds—together with a low-impedance path, any tendency for those parts to develop different voltages is minimized. This prevents arcing or spark hazards between nearby parts, reduces shock risk when a person could touch different pieces at once, and helps keep electrical noise and interference from one component to another. Grounding, on the other hand, provides a reference point and a fault return path for the system, which is a separate function from bonding. Bonding is not about shielding insulation or treating grounding as the same thing, so the primary job of bonding is the low-impedance equalization of potentials across conductive parts.