gismo
Touchdown! Greaser!
The stick on CO detectors do indeed detect CO but they don't indicate until the level gets pretty high. A small exhaust leak in the cabin heater can generate levels that cause serious impairment without the detector showing any signs of a problem. So it's true they're better than nothing because if you have a big CO leak and you happen to notice the spot changing color it could save your life. Just don't count on it.Skip - I use the stick-on detectors and they work. During a routine panel scan shortly after takeoff I noticed the color had changed to sky blue. It was the first cool morning of the season and the first time I had flown with all the fresh air vents closed. I immediately opened both wing vents in the C172 and was prepared to open my side window if needed. Took just a moment but as the cabin was flushed with air the color returned to normal. It took lots of tests with a digital CO reader before we figured out where the leak was coming from as the internal exhaust components / mufflers showed no signs of leaking. Turned out to be worn door seals.
Attached pic was taken by friend in the right seat during the flight. Here's a link to the one I have in the plane:
http://www.aircraftspruce.com/catalog/pspages/llifecodetectors.php