Alert Beware of Carbon Monoxide Intrusion

[Neal]

I learned of the Aithre shield CO detector that integrates in the G3X from the CubCrafters community and had one installed in my 2021 CubCrafters FX-3. Nothing alarming and it seemed to work well. Then came along my 2023 CubCrafters FX-3 and right off the bat I'm seeing very high CO readings and can't figure it out. Is it a bad Aithre? Was the prior one bad? Is it in a different location? What is the deal. I'm getting red alerts and thought it was just something to ignore. WRONG.

During my landing light upgrade saga I had the GDU out and saw the Aithre was located in the exact same location. As I had silicone caulk out for the landing light covers I figured I'll seal the gear leg area as I know from @turbopilot he raised a concern that this was a path for CO getting into the cockpit. Today I flew for the first time since sealing these areas and it seems the holes are larger than the last plane and sure enough PROBLEM SOLVED! I was not in the red at all today and this made the difference. Now keep in mind I have a cargo pod and that's going to make matters a little worse acting as a baffle for the exhaust which will presumably force it into these gaps.

I recommend everyone seal these openings belly pod or not. CO is poison and the factory should be sealing these gaps as well for the protection of the pilots. Don't mess with CO in your home or plane!

Shield EX 2.0 Behind-the-Panel CO Detector - With iOS App - Black

Experimental Aircraft Only: The Aithre Shield EX 2.0 is the first behind-the-panel mounted carbon monoxide detector that puts ultra-sensitive CO readings directly on your iOS device, Dynon SkyView, Garmin G3X, and Advanced Flight Avionics. Features simple 3-wire installation, a small footprint...

aithreaviation.com

 

[Kyflyer]

Thanks for sharing. I received a message from CC that they have been “dialing in” my CO2 detector. I am fearful that I may also have a leak that needs to be addressed. I plan to bring my secondary CO2 monitor when I pick up my plane just in case…

 

[Cubonaut875]

I have the Aithre detector also and have not had any readings even close to high. I'll check my landing gear tonight. Kyflyer did they put a cargo pod on your plane?

 

[Kyflyer]

No Cargo Pod but I will certainly check around the landing gear.

 

[Cubonaut875]

Attached are a couple pictures of my smoke system in operation. It seems like even without the cargo pod there is an exhaust eddy that definitely could leak up into the landing gear access. Note that in my 1954 SuperCub, even though the exhaust was shorter it was off to the side and it did not seem to curl back as the FX3 does. The seal around my gear seems tighter, but I will definitely silicone it.

 

[Cubonaut875]

 

[Cubonaut875]

 

[Cubonaut875]

 

[Kyflyer]

These pics are terrific. After seeing one of your videos I had them add a smoke system to my FX3.

 

[Cubonaut875]

I love my smoke system. Make sure they put the check valve as close to the firewall as possible. I'm still working through some smoke "Dribble"

 

[Cubonaut875]

 

[kshunz]

Neal, I saw your video on this subject today. Thanks for getting this out there -- I have a similar issue and will try sealing it up as you've done. I also have the Aithre CO detector installed. I generally get CO levels of 20-30 ppm on the ground, and 40-50+ ppm during a climb. For short durations, those aren't particularly worrisome but it would be nice to get them down.

For what it's worth, one thing in the video that surprised me was the mention of CO for longer durations in cruise. With a full-rich mixture in cruise, I do get around 10 ppm. But as soon as I lean the mixture, the CO level drops to zero and stays there as long as the mixture is lean. It's surprising how quickly that happens, which I guess goes to show how drafty the cockpit is.

 

[Neal]

In cruise mine does come down as well. I also forgot to mention one thing that may be different with my plane is the cargo pod which may exacerbate the situation. However, silicone the gaps made a huge difference, even in ground ops.