What shall not be created where they are ingested into heating and vent systems?

• A. Air
• B. Water vapor
• C. Noise
• D. Toxic fumes

Answer: (D)

The key idea is that heating and vent systems are designed to deliver breathable air by drawing in outside air or recirculating cabin air. If toxic fumes are produced near where that intake draws air, those fumes will be sucked into the system and spread throughout the aircraft. That contaminates the entire air supply, posing serious health and safety risks to passengers and crew, and can also harm equipment. Air and water vapor are normal components of the air the system handles, and while noise can come from the machinery, it isn’t a contaminant being introduced into the air stream.