According to NTSB Safety Alert 069, Pilots: Prevent Carbon Monoxide Poisoning, “Carbon monoxide (CO) is a colorless, odorless, tasteless gas by-product of internal combustion engines and is found in exhaust gases. Sufficiently high levels of CO in your bloodstream will lead to oxygen starvation and the onset of symptoms (such as headaches, drowsiness, nausea, or shortness of breath).”
It so happens that piston-powered airplanes are a frequent source of carbon monoxide poisoning. Because they are typically operated where the ambient air is thinner, there’s less oxygen content. And it also so happens that their heating systems are designed to capture residual heat from an engine’s exhaust, maximizing the chance of introducing CO into the cabin. Depending on their design, turbine-powered aircraft systems also can be a source of CO into the cabin.
