JR, also be reminded that the cheapie CO detectors (not a criticism, I use them too) have an exposure life (usually 90 days), as well as an expiration date. I bought one once that looked kinda funny before I even unwrapped it--the pilot shop I bought it at displayed them by pinning them up on a corkboard, they had punctured the sealed package by sticking the pin thru it. The same shop also sold me a detector which was expired by about a year. They did make good on them later, but it just goes to show ya that ya take a hard look at everything.

Eric

Great writeup, Jr. I guess I'm glad to be the guy that put you over the edge. Glad you persisted and found the problem. And, you're right. What the fuck do I know? Just that prior to Aug 20, you hadn't written a story about huffing a huge quantity of CO and getting your brains scrambled.

Thanks for sharing man, as a soon to be 170 owner it is one more thing I'll be keeping an eye on.

I find it laughable that someone suggested you might be hypoxic at 8500 ftm, and spend time in the hyper(o?)baric chamber to find your limits.

Occam's Razor, man.

Z

Jr.CubBuilder wrote: It has been a learning experience for me, both in airplane maintenance, and also in human nature. The later part of that I say because I was somewhat taken aback by the reactions of more than a couple of my pilot friends when I related my experience to them. Several have suggested that I was “hung over” (Doug I think you were being facetious, and if you weren’t that’s ok) another suggested that I was hypoxic and I should go to Spokane and get some time in an altitude chamber to find my limits, and a couple more just obviously thought I had imagined the whole thing.

Actually I was being facetious and serious at the same time. I found myself compromised by a hangover on Saturday morning. Felt fine when I woke up after a night of too much fun, said to Alyce 'let's go to Sulphur Creek for breakfast', and as soon as we were off and cruising at 8500' I didn't feel nearly as good as I did when we climbed out of the sleeping bag. Had a dull headache crawl into the back of my head that didn't go away till the end of the day.

I'm not trying to discount the possibility of a CO leak into your cabin, just trying to mention that you could have been suffering from a combination of symptomatic effects of CO, altitude, the increased pressure of canyon flying, and partying. These things can all add up to much more than any single one of them would in these circumstances.

A leak in your firewall, eh? The cowling is a pressurized compartment and the airflow characteristics can change dramatically inside it in different phases of flight. A leaky firewall could cause a serious problem in the right(wrong) conditions. CO from the engine compartment could have been blowing into the cabin under pressure during your climb out through just a small hole in the firewall. Haven't heard of many aircraft exhaust systems that are completely tight from the exhaust port to the pipe tip, so an air tight firewall is really important.

That's an exhaust muffler? Looks more like an anti-ship mine to me Where exactly was that leak coming from? I'm also surprised that those slip fittings are so close to the heater shroud.

I thought it was the tentacle of a giant octopus.
Re: hypoxia at low altitudes (8500')-- anyone other flatlanders here ever spent time hunting in the mountains? You don't have to be at 12-14,000 feet to suffer from the lower amount of oxygen in the air--shortness of breath, headache, lack of concentration & stamina, etc can result. I think experiencing some effects of oxygen deprivation at 8500' is not impossible, given the stresses of mountain flying along with maybe not enough sleep, a bit of a hangover, some get home-itis, etc. It can be deadly combined with more CO than is healthy for you. Glad it was a learning experience for you JR not a lethal one.

Eric

Hypoxia at altitudes as low as 8000 does occur, but the amount of time spent at those altitudes in a small plane is very short(what's the endurance on your small plane? 5 hrs?), compared to ground dwelling, like on a hunting trip or mountaineering, where you never get back down to the lower altitudes and the thick air, until you return.

Altitude sickness can happen at less than 8,000'. Depending on various health factors of the individual.....age, smoker/non-smoker, physical conditioning, illness etc.

A person living everyday life at an altitude of 6500' thats young, in good shape, non smoker may not suffer from hypoxia until well beyond 12000'.

An aging, smoking, fast food eating couch potato living at sea level may feel the effects of hypoxia on the upper third level of a tri-level house.

It goes without saying Carbon Monoxide (CO) poisoning can happen at any altitude and should not be confused with Hypoxia. In either case, the O2 bottle could save your life.

Hypoxic effects start as low as 2000" ft. You begin to lose some night vision there. "average military aviator" A smoker is physiogicaly at 3000" at sea level. CO effects are cumulative, they do NOT wear off in a few minutes. I have forgotten how much more likely a CO molecule is to bond with hemoglobin than an O2 molecule, but it's in the thousands. All of that crap I had to regurgitate every year for twenty years.
I suspect your experience was a chain of events, that's why it was so hard to figure out.
You smoke, you were at altitude, maybe tired, a little hung over, probably still had CO poisoning from the day before etc. Just glad your still here

Another way to check for leaks is with sopy water. Filll a spray bottle with water, add some dish soap. Shake it up a bit. Pressurize the system with air as JR described. Then just spray. Any leaks will show up real quick. This is how we test gas pipes in your house.

Excellent article and excellent job of deducing what happened!! I wont sign an annual on anything without a pressure check of the exhaust.. I use a big shopvac and soapy water, with the exhaust off the aircraft. I also agree totally with you about the clamps that are supposed to be sealing... very very few ever do seal anything! I've had owners really squawk when I insist on replacing them because they're bent and loose.
I also agree on the importance of the firewall being sealed..your's is a very good job of explaining that. I agree on the probability of a bunch of factors being added up to the condition you experienced, it's usually not just one thing that does it to ya.
I commend you once again on a fantastic article, and I'd love to see that submitted to a few paper magazines... lots of people, both pilots and mechanics as well, could learn from your experience!!
JH

hardtailjohn wrote:Excellent article and excellent job of deducing what happened!! I wont sign an annual on anything without a pressure check of the exhaust.. I use a big shopvac and soapy water, with the exhaust off the aircraft. I also agree totally with you about the clamps that are supposed to be sealing... very very few ever do seal anything!

Good post. One question - why do you take the exhaust off of the aircraft for this test? It seems to me that it could be done on the plane. Or are you saying that you normally remove the exhaust for other reasons during the annual?

Just curious.

Jr. CubBuilder is exactly right, and you also can't see the can well enough to see if anything is about to happen... alot of times I've seen a slight swelling in a can... a definate problem in my book!! I'm suprised that so many people take their exhaust so much for granted... like I was always told, carbon monoxide is a silent, but very deadly killer!
JH