Carbon monoxide in cockpit

benyflyguy

benyflyguy

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benyflyguy
C02611CC-2884-4696-AB75-71660B2AAA2B.jpeg I fly a c182H. I just took a longer trip and brought my sensacor CO digital detector. Ground inside cockpit no engine reads 0-1
Startup and sitting still rpm 1000 reads 1-3.
Climb out around 1-5.
level flight 8000’ cowl flaps closed no heat or defrost on reads around 12-20.
I keep the window vents open getting fresh air all the time. But I find it odd that I’m getting any CO in the cockpit. The slipstream from exhaust wouldn’t make it up to those vents at 120kts right?? While getting cowl flaps redone I am going to ask mechanic to look for a possible exhaust Leak.
Am I over reacting to those CO readings??They are low and would take awhile to ever cause a problem. The meter seems good. I moved it around the cockpit and get some varied readings. Most of the readings I took was hanging on pilot pocket just below the vent.
 
Perhaps coming through the firewall? We saw 65 today while briefing the takeoff in calm wind. Typically see mid 30s during Vy climb and straight zero at cruise.
 
CO is tricky. Remember, the cockpit is a low-pressure area, so if CO has a chance to come in, it WILL come in. Check the seals around the main landing gear, and the aft bulkhead in the cabin (CO can enter the tailcone and come forward). Put someone in the rear seats and, if you can, have them get a meter reading in the baggage area.

12-20 PPM isn't bad, the warning threshold for household meters is 30 ppm and the first danger threshold is 50. Keep in mind, though, that it's not just the amount of CO, it's the duration.

I have a portable CO detector that I take flying in my open-cockpit airplane every once in a while. High value I saw was 80 PPM; that was momentary while taxiing when a crosswind swirled the exhaust into the cockpit. I see 10 ppm or so at cruise, heater on or off, with spikes to 16 during full-power climbs.

And yes, you CAN get CO poisoning in an open-cockpit airplane. I had it once (in a Mooney) so I'm a bit more cautious than some.

Ron Wanttaja
 
Same CO detector as you in a 182P. Ours is mounted on panel (right side). During run up can go as high as 15-20. Taxi and idling around 4-8. In cruise never above 2. Flew 500 miles friday, cruise at 7500msl and 150mph and never above 2. But we only have the two wing events and the one floor vent. All of our idle and run up numbers are with pilot side window open.

I would move it to the opposite side once just to make sure are truly getting the highest reading. What if it's worse than what you are reading.

You are not over reacting.

What is weird is your numbers are the opposite of ours. Ours are worst in run up and idle and almost non existent in cruise. But ours is stock exhaust and maybe you have different mods.
 
wanttaja said:
12-20 PPM isn't bad, the warning threshold for household meters is 30 ppm and the first danger threshold is 50. Keep in mind, though, that it's not just the amount of CO, it's the duration.
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I believe altitude figures into it, too.
 
Canada has an AD that applies to all aircraft that use the exhaust system as a source of cabin heat. Annually or every 150 hours, whichever comes first. It can be a pain, but sometimes we've found leaks developing. I met a guy that bought an old Cherokee, and on its first annual the (new) shop did the AD properly and took the heat muff off. Saw something serious in there, like a hole you could put your fist into. Took the muffler off and it fell apart in two pieces. "No wonder I was getting headaches every time I went flying," he said. And he hadn't used the cabin heat yet, either. If he had he likely wouldn't be alive today.

https://wwwapps.tc.gc.ca/Saf-Sec-Sur/2/cawis-swimn/AD_html.aspx?file=CF-90-03R2-E.htm
 
Mine will alert if the door is cracked or the side window is open.....
 

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Checkout_my_Six said:
Mine will alert if the door is cracked or the side window is open.....
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That is the same one I use. Trying to find the clip-on carrier that is supposedly available. Would make it a lot more portable that way.
 
Dan Thomas said:
Canada has an AD that applies to all aircraft that use the exhaust system as a source of cabin heat. Annually or every 150 hours, whichever comes first.
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The FAA has a FAR 43-D item
(8) Exhaust stacks—for cracks, defects, and improper attachment.

Pretty much covers it.
 
I will see detectable levels on the ground taxiing with the canopy cracked. Never see anything in flight. If it changes when using cabin heat you may have a exhaust muff leak.
 
Tom-D said:
The FAA has a FAR 43-D item
(8) Exhaust stacks—for cracks, defects, and improper attachment.

Pretty much covers it.
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It should cover it. In Canada we have the equivalent to that:

Standard 625 Appendix B: Maintenance Schedules - Canadian Aviation Regulations (CARs)
(i) Exhaust stacks - inspect for cracks, defects and improper attachment;

But it was never enough. Accidents happened because the exhaust system wasn't getting inspected nearly well enough and pilots would be incapacitated and crash. The AD was written to force the mechanic to take things apart and do it right. And, as I have mentioned, that is sometimes not enough either. People are lazy.

The AD stipulates a pressure check if there are any suspect areas. I usually did the pressure check anyway, since I had found that the soap would identify leaks I would never have seen, and I also soaped the risers and sometimes found impending failures there, or failing exhaust gaskets.
 
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A friend of mine who has a Nanchang says you can’t put your sensor on the floor because the co fills the bottom of the cockpit, but by design it doesn’t come above the seats.
:eek:
 
Salty said:
A friend of mine who has a Nanchang says you can’t put your sensor on the floor because the co fills the bottom of the cockpit, but by design it doesn’t come above the seats.
:eek:
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perfect.....just keep your head off the floor. :D
 
smv said:
Yours came with a carrier has a clip that can be actually clipped to a lapel, flight bag, map pocket, etc?
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Mine came with the clip too. But I already lost it. We velcro it to the panel.
 
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The CO detector goes off in the Navion if you've got the canopy open and there's not much wind (or forward taxi speed).
 
Dan Thomas said:
It should cover it. In Canada we have the equivalent to that:

Standard 625 Appendix B: Maintenance Schedules - Canadian Aviation Regulations (CARs)
(i) Exhaust stacks - inspect for cracks, defects and improper attachment;

But it was never enough. Accidents happened because the exhaust system wasn't getting inspected nearly well enough and pilots would be incapacitated and crash. The AD was written to force the mechanic to take things apart and do it right. And, as I have mentioned, that is sometimes not enough either. People are lazy.

The AD stipulates a pressure check if there are any suspect areas. I usually did the pressure check anyway, since I had found that the soap would identify leaks I would never have seen, and I also soaped the risers and sometimes found impending failures there, or failing exhaust gaskets.
Click to expand...

Don't forget the owner's role in this. I like showing the owners what the AD or SB or manual requirements actually do say.
 
I see about 1-3ppm in cruise...going to try those vents or sealing the tail cone!
 
When my airplane was pretty new to me, and I first bought a digital CO detector, I took some friends flying one day. One of them was a bit chilly, and closed off the cabin air vents while I wasn't looking, which apparently caused some carbon monoxide to accumulate in the cabin. When my detector alerted, I landed and had a shop check the exhaust system for leaks before we decided there was nothing there that should keep us from continuing home.

Later on, I chased the leak for months before I gave up on it. That included plugging every gap in the firewall, replacing all of the cabin and baggage door and window seals, replacing some window sealant that was cracking, and even duct taping all of the floor panels and the tail cone. I even let one shop talk me into replacing my entire exhaust system at considerable expense, which I now know to have been wholly unnecessary, and am pretty embarrassed about having done. (Luckily, the after-market exhaust system for the 210 is actually a useful upgrade to do anyway.)

In the end, having fixed every conceivable problem, I now fly with a bit of cabin air, and the positive pressure does just fine to keep the CO out of wherever it's coming from. I keep the digital detector going to monitor, and I'm very comfortable with that. I've come to learn that it isn't an uncommon thing. The digital detectors are all a lot more sensitive than the junk "CO detectors" made of cardboard, not to mention the household CO detectors that keep us alive at home.

This isn't to say at all that you shouldn't take it seriously—especially if something has recently changed—but I just thought I would share. IMO the single best thing you can do is velcro your CO detector to the panel and turn it on every time you fly.
 
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