Carbon Monoxide Detector Variability. What numbers should be expected on the carbon monoxide detector?

Q I got a carbon monoxide detector after hearing Max Trescott’s podcast on the subject. I shared it with my students too and almost all of us bought one. I’ve been using it for nearly 6 months now and I wanted to share and compare with others’ experiences.

1. I never see zero. Well, if I turn it on outside, but it is never zero in a running plane. I’ve gotten it down to low single digits but not zero. The highest readings come from idling on the ground when not moving.

2. I can tell when I have leaned or not. Leaning does some to lower the value — whether airborne or on the ground.

3. Retiming my mags lowered the value. The values were getting too high on the ground. I had the exhaust inspected the same time I had the mag retimed and the timing advance turned on my SureFly mag. It lowered my values to an average in line with the other airplanes I fly.

Paul Wurster

A I do see zero in flight and sometimes on the ground while taxiing but it’s usually in the low single digits. When I forget to lean, it will pop up to above 50 ppm and start its way down after I lean or after I taxi and get some air circulation. I try to pay close attention in the colder months after I turn on the heat in case of a leak into to heating system.

Marco Leon