182RG Reported Carbon Monoxide (likely coming from wheel wells).

Scott ShererScott Sherer COO Forum Moderator

I've had 182RG's for years and my most recent one I have a great digital CO reader (now that we all have the digital CO Detectors sold at any hardware store that we carry in cabins. << Scratch that for obvious reasons). About 6 years ago, after I got my digital CO, I saw the CO reading in ppm rise very high on high AOA situations (particularly climb out - - which for me could be a long time in SoCal since I'd go to 14k and cruise there). At cruise I wouldn't have the problem but didn't like being exposed to high levels for a half hour. I set to work big time. Had the entire exhaust overhauled. No luck. Resealed the entire thru-cables etc of the firewall and damn-well everything else you could think of. Even all door seals resealed (I was positive that would solve it, since this was near the end of my forensic search) -- and yes the wheel wells too.

AND THEN the last thing to look at (and yet now that you look at it . . IT SHOULD'VE BEEN THE FIRST THING I looked at, since it seems so obvious now, and that every other 182RG pilot should look at) is the rear cabin door latch!!! Look at it. It's a perfect aerodynamic air scoop facing into the oncoming wind (and exhaust flow). When you take the liner out of the baggage door and look at the baggage door thumb-latch (read: air scoop) you can see how the exhaust that comes from the left side of the plane wraps straight up to that air scoop after take off and gets sucked immediately/perfectly into the cabin. We resealed that rear baggage door and re-seated the latch (read: air scoop, perfect-designed-exhaust-scoop) and sealed the inside cover around it -- and oila! Problem solved. My digital CO has read "0" ppm for all phases of flight in all conditions. Please make sure this info gets to that pilot inquiring (and others). Could save their lives.

I can't help but wonder how many 182RG pilots have been sucking on CO for years and not knowing -- I've even read about a couple of accidents (read: 182RG in Santa Monica airport approach where pilot went incommunicative and went straight into a mountain about 3 or 4 years ago for no reason). The CO is not insignificant - - mine was reading 200 ppm to sometimes 400 ppm. So you really need to get the word out. Frankly, IMHO there should be an AD out on that air scoop (I mean rear-baggage thumb-latch)

Jeff Meshinsky

Scott Sherer
Wright Brothers Master Pilot, FAA Commercial Pilot
Aviation Director, Cessna Owners Organization Forum Moderator and Cessna Owners Author.

Need help? Let me know!

Comments

  • Jeff, my co-owner and I are chasing down a similar issue in our TR182. After chasing all the items you did prior to the latch, we see peaks of over 200ppm in the baggage area.

    We've had the door seal removed and replaced, and taped over the baggage door latch on the outside to simulate a seal. Our test setup includes a sensor on the floor up front by the fuel selector (reads 0), another on the floor in the passenger area (reads 0), and another in the baggage area (+200ppm peaked)

    Interestingly, it does seem that the CO increases on climb out, and after retracting the gear. Our mechanic said our next check would be to look at the gear bay tunnels (plastic) for a crack that opens when the gear is retracted.

    Any thoughts as an "experienced" CO sleuth? Thanks in advance. . .cd

  • I just spent a couple days working to reduce exhaust ingress on our R182. The job started with a couple pleasant hours under the airplane, spraying solvent and using a scrub brush to clean years of accumulated gunk off the tunnel and wheel well liners. In the process the rest of the belly was thoroughly degreased.
    A detailed visual inspection of the now-mostly-clean liners determined that the tunnel liners looked pretty good. However, the wheel well liner had noticeable gaps to the skin and the longitudinal bulkhead that runs fore and aft at the bottom of the wheel well.
    It appears that Cessna applied a hard caulk material at those joints when the airplane was assembled. I think it's likely that they used fuel tank sealant, but the maintenance manual does not appear to specify. Apparently some of that factory-applied sealant had come loose, and a previous maintainer resealed the joints with white RTV. Sadly, RTV will not hold on long with the constant flexure and oil present at those joints. Took another hour or two to scrape off the RTV residue and really clean the joint for re-seal.
    I am pretty sure that the air flow in that area pressurizes the wheel well during high AOA flight (climb or slow flight), so any exhaust gets blown through the gaps into the tail cone and under the cabin floor. Once the weather clears I will go back and do a test flight to see if the CO levels in the cabin are back to near-undetectable. I have great expectations.

  • Scott ShererScott Sherer COO Forum Moderator

    Fingers crossed on this one. I'm impressed by the effort it took you to research what Cessna did during manufacture of the plane and the effort you've taken to resolve it. Very cool. Do you think you could write an article for Cessna Owners magazine with a few pics of this? I think all of our members would be interested in your experience.

    Scott Sherer
    Wright Brothers Master Pilot, FAA Commercial Pilot
    Aviation Director, Cessna Owners Organization Forum Moderator and Cessna Owners Author.

    Need help? Let me know!

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