FAA Powerplant Written Practice Test

What material should be used to tie aircraft wire groups or bundles where supports are more than 12 inches apart?

1. Plastic cord

2. Waxed cotton cord, nylon cord, or fiberglass cord

3. Metal wire

4. Rubber bands

The correct answer is: Waxed cotton cord, nylon cord, or fiberglass cord

When tying aircraft wire groups or bundles where supports are more than 12 inches apart, waxed cotton cord, nylon cord, or fiberglass cord are the recommended materials because they offer the necessary strength and flexibility without causing damage to the wires themselves. Using materials like these ensures that the bundles are secured effectively while also maintaining the integrity of the wiring. Waxed cotton cord has resistance to moisture and abrasion, nylon cord is known for its elasticity and durability, and fiberglass cord is able to provide strong support without adding significant weight. These materials do not conduct electricity, which is crucial in aviation applications to prevent interference with electrical signals. Additionally, these types of cords can withstand various environmental conditions without degrading, making them suitable for the demands of aircraft use. On the other hand, plastic cord may lack the necessary strength and resistance to environmental factors that are critical in aviation contexts. Metal wire, while strong, could potentially short circuit the wires it is securing. Rubber bands, on the other hand, can deteriorate over time and may not provide a reliable long-term solution for securing wire bundles.