The air conditioning distribution system routes conditioned air to pressurized compartments using what type of ducts?

• A. Thin-wall aluminum or fiberglass ducts
• B. Steel ducts
• C. Copper tubing
• D. Plastic hoses

Answer: (A)

Air conditioning in pressurized aircraft uses lightweight, durable ducts made of thin-wall aluminum or fiberglass to route conditioned air to compartments. The thin walls reduce weight, which is crucial in aviation, while still withstanding repeated pressurization cycles and temperature changes. Aluminum provides rigidity and corrosion resistance, and fiberglass offers good insulation and heat resistance, helping keep the air at the desired temperature with minimal losses. Heavier steel ducts would add unnecessary weight and are harder to route around complex airframe shapes. Copper tubing is used for refrigerant piping, not for delivering conditioned air to cabins, and plastic hoses typically don’t meet the fire, temperature, and pressure safety standards required for primary cabin air distribution.