Carbon Monoxide For Renters: A Tale For The Season

Carbon monoxide (CO) is a natural by-product of combustion, it is poisonous and, as long as your engine is running, it is present near your cockpit. The cabin of your airplane is normally sealed to prevent carbon monoxide poisoning. If the seal is broken, however, CO gas can be deadly.

A friend of mine recently earned his Private Pilot certificate, and had just checked out in a Cessna 182. We planned to combine a mutual business trip with a little quality control check of his piloting skill; my friend flew the Skylane while I observed from the right seat.

To make it to our meeting on time, my friend picked up the airplane from its home base the evening before, repositioning it to a closer airfield for a morning departure. Wanting to get night current, he made the appropriate full-stop landings before putting the 182 in our company’s hangar for the night.

My friend didn’t notice it at the time, but later he recognized he’d made a few mistakes the night before. He’d radioed his intentions to land on Runway 21 when in fact he landed on the reciprocal Runway 3. He remembered being a little sloppy on the controls. It took a great deal of exertion to push the airplane into the hangar.

By the time he got home, he had a whopping headache and was very fatigued. He complained of blurred vision, and was extremely sensitive to even the smallest noises. He planned to spend the evening reading the 1821s flight manual, but ended up going to bed early to help relieve the symptoms. The next morning, when he got up, he immediately recognized his experience as a dose of carbon monoxide poisoning.

CO is an odorless, colorless gas. Sometimes, CO is accompanied by smoke or smells from other combustion, but it can affect you without any visible cues. Carbon monoxide molecules take the place of oxygen in your blood’s hemoglobin, and without oxygen flow to your tissues, discomfort, pain, degraded decision-making, unconsciousness and even death can occur.

Airborne CO exposure most commonly results from a leaky exhaust-muff heater, which allows combustion gases access to the cabin through your cabin heat vent. You can’t be sure that’s the source of a leak until a mechanic checks it out, so simply flying with the heater turned off may not protect you. There are several electronic “sniffers” on the market, which sound alarms when they detect unsafe levels of CO. Most popular, and at least as effective as more expensive sniffers, are the disposable CO detector “spot” cards — the ones that turn dark when exposed to harmful levels of carbon monoxide. In fact, my friend had one of these cards with him during the evening flight, but decided not to open it and stick it in the airplane, because he’d only be making the one trip in the 182.

Here, Spot
My friend wisely decided against making the trip in the Skylane; I flew us in the company Baron instead (always carry a spare airplane). Later, we took the 10-minute trip to return the Skylane to its home, careful to watch each other for signs of CO exposure. And my friend has a new procedure — he flies with a CO “spot” card stuck to his kneeboard, easy to take from one rental plane to the next.