CO Leak

[JJ Campbell]

My SLSA Tecnam Eaglet has CO leaking into the cabin. I have a CO monitor and I can keep the level down to zero. Unfortunately, to do this I have to keep the two small portals in the side windows open. In the Summer this is not too bad but, in the Winter, I get very cold and uncomfortable. For the last two years during my conditional inspections the aircraft mechanics (two IAs) have looked for and corrected any exhaust leaks they could find, or thought were suspect. Sadly, the problem persists, and temperatures are dropping.

My question: is there anything (preferably an aerosol spray) that can make this invisible gas visible?

[3Dreaming]

The muffler needs to be removed and pressure tested. That is the only way to find the leaks. I have one off a CT sent out right now with two spots that were submitting CO into the cabin heat system.

[Warmi]

Well, I could never keep CO2 levels down to zero - during run up or right after landing, it goes up to about 15-20 PPM for a short time ( a few minutes ) - I though it was fairly normal.

[drseti]

You may wish to view my webinar "Surviving Carbon Monoxide," describing a similar problem I encountered about two years ago, and what I did about it. Video at:

https://avsport.org/webinars/videos/co.mp4

[JJ Campbell]

Well, I could never keep CO2 levels down to zero - during run up or right after landing, it goes up to about 15-20 PPM for a short time ( a few minutes ) - I thought it was fairly normal.

I could live with that, but I am getting escalating levels during cruise. If I close both portals to get some heat in the cabin, levels start to rise in 10 or 15 seconds. I've never let it get above the mid-teens.

[JJ Campbell]

The muffler needs to be removed and pressure tested. That is the only way to find the leaks. I have one off a CT sent out right now with two spots that were submitting CO into the cabin heat system.

I'll ask to get that done during my next conditional. In case the IAs don't know already, where do you get this test done? Also, would a new muffler cost a lot more than this test?

[JJ Campbell]

You may wish to view my webinar "Surviving Carbon Monoxide," describing a similar problem I encountered about two years ago, and what I did about it. Video at:

https://avsport.org/webinars/videos/co.mp4

Please don't take offence but can you give me the time stamp for where to find the similar problem? I don't want to spend 90 minutes watching the entire video. I've already spent a lot of time on CO education.

[3Dreaming]

The time consuming part is removing the muffler for the test. In this case I already had it off doing a rubber replacement.

Muffler test.jpg (18.38 KiB) Viewed 24672 times

I have 4 plugs that are made from https://www.aircraftspruce.com/catalog/ ... dseals.php and a bolt, nut, and two washers. You can tighten the nut to tighten the plug in the hole. To connect to the tailpipe I use https://www.aircraftspruce.com/catalog/ ... -03700.php coupled to my shop-vac blowing air. Use what ever connection works best for your shop-vac. I just used what I had laying around. Spray soapy solution and watch for bubbles. Mark where the bubbles are and get the muffler repaired or replaced.

[3Dreaming]

A new muffler will be over $1,000 by the time it is ready to install, and maybe more if Tecnam didn't use a stock Rotax part.

[3Dreaming]

A picture of my plug. I have 4 of them.

[drseti]

Please don't take offence but can you give me the time stamp for where to find the similar problem? I don't want to spend 90 minutes watching the entire video. I've already spent a lot of time on CO education.

No offense taken, but all my webinars are official FAA Safety seminars. You should really watch the whole presentation, to put the issue in context. Investing an hour and a half in study just might save your life some day.

(And BTW, since I've done over 50 of these videos, I certainly don't know the time stamps for each portion of each presentation.)

[drseti]

A new muffler will be over $1,000 by the time it is ready to install, and maybe more if Tecnam didn't use a stock Rotax part.

Not to mention that, if the muffler is failing, it's likely the rest of the exhaust system is about to as well. Whenever I replace a muffler, I also replace the pipes and heat muff while I'm at it (as mentioned in the above-referenced webinar).

[fatsportpilot]

My question: is there anything (preferably an aerosol spray) that can make this invisible gas visible?

There is nothing that can make it visible. There are probably chemicals that can react with it and turn it into a visible gas, but then it wouldn't be CO anymore (and those chemicals are probably very toxic themselves and only used in synthetic chemistry labs).

CO is only toxic because it blocks oxygen in your blood cells. A small amount of CO is pretty harmless as long as it doesn't cause hypoxia (and our bodies actually naturally produce a tiny amount of CO). If you have a small amount then I wouldn't worry, as long as you are monitoring it and make sure it does not rise to a harmful level. My real worry wouldn't be the CO but the other pollutants that are with it. If you have an exhaust leak then you're also breathing in particulates and NOx products which are harmful with prolonged exposure.

15-20 ppm causes reduced vigilance and impaired performance according to the WHO which is relevant to pilots even though it is not toxic at that level per se. ACGIH says the 25 ppm is safe for up to 8 hours exposure and 35 ppm will cause physical symptoms in 6 to 8 hours. But even levels as low as 10 ppm can be dangerous to people with heart problems. https://www.spec-sensors.com/wp-content ... Levels.pdf

Btw pulse oximeters will be fooled into thinking CO in the blood is O2 so it's not accurate if you have too much CO in the air.