I keep a Sensorcon in my aircraft. It's inexpensive, high-quality, potentially life-saving gear. Not sure if there's an argument to be made against keeping one in the cockpit, unless you fly a glider. From what I've learned about the stick on cards, they're borderline useless after a short time in the aircraft.
It’s a 200 hour turbocharged engine with no problems. There’s likely to be some leakage at the slip joints in the exhaust. These ducts are at just the right place where the downflow goes out of the cowling. Someone told me they just run it full heat and balance the temperature with the air vents. That would close up the opening in the duct in the cowl as much as possible too. I’m curious if anyone else sees low levels on their meters.
I was going to buy the Sensorcon but for some reason it says it cant be delivered to California so I bought the Forensics Detector off Amazon. I watched a few comparisons and its a good little detector. The battery lasts over a year and I just leave it on. It came with a handy little mount that I stuck to my panel and it has an audible alarm as well as a flashing light.
here's mine....it's cheap insurance and very sensitive. It alerts if I open the side window or door. Amazon has them....seems to work well. No alerts, so it must be good. lol https://www.amazon.com/Aircraft-Mon...7?keywords=co+detector&qid=1583584410&sr=8-27 View attachment 83378 View attachment 83379
I believe anything under 70 is usually considered safe for fairly long exposure. In my 69 Cardinal, I see 16-20 with the vents closed up. Drops close to zero when I turn on the cabin heat. Not at all what I expected given that I was checking for leaks from the muffler.
Take it for what it's worth, but this reference claims OSHA has a 50 ppm limit over 8 hours https://gaslab.com/blogs/articles/c...personal exposure limit,an 8-hour time period.
I would not rely on the OSHA recommendations for CO exposure for aviation operations for several reasons, the most important of which are that these limits are based on sea level partial pressures of oxygen (about 120 torr). At 10,000 feet, the partial pressure of oxygen is down to a little over 80 torr. At altitude, the effects of CO poisoning will be amplified due to several effects, including (1) lower hemoglobin-O2 saturation, which will allow higher hemoglobin-CO occupancy at altitude than at the same CO concentration at sea level, (2) lowered blood CO2 levels, which will decrease the ability of hemoglobin to release O2 to tissues or relinquish CO (indirect Bohr Effect), and (3) additional degradation of the ability of hemoglobin to release O2 to tissues due to the increased occupancy of hemoglobin by CO. (This latter effect it the primary reason that CO is a physiological poison. 25% occupancy of hemoblogin by CO is enough to effectively prevent oxygen delivery to tissues. Oxygen remains stubbornly bound to hemoglobin.) It is estimated that sustained exposure to 50 ppm CO increases the effective physiological altitude by about 5000-6000 feet. That level of CO could push a healthy pilot flying at 9,000 or 10,000 feet beyond effectively safe oxygen altitudes. Those in less than superb cardiovascular condition could encounter hypoxia symptoms at lower altitude in the presence of CO. Remember, your amperometric CO detector measures absolute concentrations (pressures) of CO. As you increase in altitude, the ratio of that (constant) CO concentration to oxygen concentration increases for a particular "ppm" reading. It is the CO/O2 ratio that determines how effectively CO can compete with oxygen for hemoglobin binding. I would not regard any persistent level of CO in the cockpit as safe during flight. My CO meter reads zero in flight. During taxi, I occasionally see up to 10-12 ppm wafting through the open canopy, presumably from exhaust pipe discharge being swirled around by the propeller.
I've shared this video of mine before. No matter which unit you end up getting, you can at least see how they operate in my testing. My CO monitor gave an early warning of an exhaust failure. Definitely worth getting one.
Ive read that its a bad idea to put it next to the tailpipe, as the extreme amount of CO and deteriorate the sensor
