Which method of air pre-heating functions strictly operates off on-board battery voltage?

Which method of air pre-heating functions strictly operates off on-board battery voltage?

• A. Electric Air Heater
• B. Heated Intake
• C. Solar Air Pre-heater
• D. Glow Plugs

Answer: (D)

Glow plugs are the method that heats the incoming air using only electrical power from the aircraft’s battery. They’re direct resistance heaters placed in the intake path and are energized during cold starts, so the air entering the engine is warmer without needing exhaust heat, solar input, or other heat sources. This makes their operation strictly tied to the onboard battery voltage. Electric air heaters, heated intakes, and solar air pre-heaters rely on other energy sources or bus power beyond a direct battery-only supply, such as the aircraft’s electrical system, exhaust heat, or solar energy, which is why glow plugs are the best match for strictly battery-powered pre-heating.

Glow plugs are the method that heats the incoming air using only electrical power from the aircraft’s battery. They’re direct resistance heaters placed in the intake path and are energized during cold starts, so the air entering the engine is warmer without needing exhaust heat, solar input, or other heat sources. This makes their operation strictly tied to the onboard battery voltage.

Electric air heaters, heated intakes, and solar air pre-heaters rely on other energy sources or bus power beyond a direct battery-only supply, such as the aircraft’s electrical system, exhaust heat, or solar energy, which is why glow plugs are the best match for strictly battery-powered pre-heating.