Plain English Meaning

A poisonous gas you cannot see, smell, or taste. It cuts off the oxygen supply your body needs, even though you keep breathing normally. In small aircraft, it most often sneaks into the cabin through the heater.

Full Definition

A colorless, odorless, tasteless gas produced by the incomplete combustion of fuel. When inhaled, it binds to hemoglobin in the blood far more readily than oxygen, reducing the blood's ability to carry oxygen to body tissues, including the brain and eyes. In aircraft, it can enter the cabin through a cracked exhaust manifold or a leaking heater shroud, since most piston-engine cabin heaters draw warm air across the exhaust system.