FAA Powerplant Written Practice Test

Under what condition is aluminum preferred as a conductor in aviation?

1. High altitude operations

2. When the intensity of corona is a concern

3. In low voltage applications

4. For high-frequency signals

The correct answer is: When the intensity of corona is a concern

Aluminum is preferred as a conductor in aviation when the intensity of corona is a concern. Corona discharge occurs when the air surrounding a conductor becomes ionized due to high electric fields, typically found at high voltages. This ionization can lead to electrical leakage, power loss, and potentially damage to systems. Aluminum is chosen in these scenarios because it has a higher breakdown voltage compared to copper, allowing for a reduced intensity of corona discharge under certain elevated conditions. Additionally, aluminum's lower density and cost-effectiveness make it advantageous in aviation applications, where weight and expense are critical factors. While other options might seem relevant, they do not align as closely with the specific properties and applications of aluminum in aviation electrical systems, especially concerning minimizing corona discharge.