Resistance through the aircraft is negligible provided what condition?

• A. The structure is adequately bonded
• B. The wires are insulated
• C. The aircraft is pressurized
• D. The aircraft is unpainted

Answer: (A)

The airframe can carry a negligible resistance return path only when the structure is adequately bonded. Bonding ties all conductive parts of the aircraft to a common electrical potential, creating a low-impedance path for return currents. When every joint and component is properly bonded, the majority of the circuit current returns through the metal skin and bonding network rather than through higher-resistance routes, keeping voltage differences small, reducing stray currents and EMI, and improving safety. Wires being insulated, pressurization, or being unpainted do not by themselves guarantee this low-resistance path; bonding ensures a continuous, shared electrical ground across the airframe (and paint must be removed at bonding points to maintain metal-to-metal contact).