Why you need a good carbon monoxide detector

Martin Pauly

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Martin Pauly
First-hand story from a survivor of a crash - Dan Bass became unconscious in his Mooney due to carbon monoxide poisoning. When he came to, he found himself on the ground in the badly damaged plane.

I should stop telling the story, and let Dan speak for himself:


Please get a good CO detector for your plane. The little tabs are not going to save you.
 
Wow, what an amazing story. So what do pilots carry in their airplane?
 
Check out Aithre.

We have their Illyrian sensors. Won’t be long before we invest in their carbon monoxide sensor.


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I watched that interview and immediately ordered a CO detector! I had been using a "home" style device but after reading the AvWeb reviews and that video I decided to go for a real device. I always have an air vent open in addition to the heater BUT that is no guarantee against insidious CO poisoning. That story was truly one for the books. Thanks for the link, Martin!!!
 
I've got a good one, and get different readings in different planes, ranging from 0 to low double digits. Home units don't alarm until very high levels, but you're not flying a house. So what level of CO in the cockpit is grounds for concern?
 
My Sentry was alarming at anything over 70ppm, and not resetting. I bought a cheap Chinese CO monitor with instantaneous readout. My CO readings get up to about 85-87ppm for a few seconds in a turn, then go back down near zero. Just a minor annoyance of have open stack exhausts. I still carry the Chinese CO monitor on every flight.

Those little paper ones work pretty good, I've watched them turn grayish, then back to orange. You just gotta remember to change them. If you wait till the expiration date, they've already just about quit working.
 
I've got a good one, and get different readings in different planes, ranging from 0 to low double digits. Home units don't alarm until very high levels, but you're not flying a house. So what level of CO in the cockpit is grounds for concern?

https://www.cpsc.gov/Safety-Educati...-Center/Carbon-Monoxide-Questions-and-Answers
What CO level is dangerous to my health?
The health effects of CO depend on the CO concentration and length of exposure, as well as each individual's health condition. CO concentration is measured in parts per million (ppm). Most people will not experience any symptoms from prolonged exposure to CO levels of approximately 1 to 70 ppm but some heart patients might experience an increase in chest pain. As CO levels increase and remain above 70 ppm, symptoms become more noticeable and can include headache, fatigue and nausea. At sustained CO concentrations above 150 to 200 ppm, disorientation, unconsciousness, and death are possible.
 
One other point to add. CO concentrations quoted in the article above are based on sea level. At 10 or 12k MSL, I would not want to use 70ppm as an upper limit. The one other point, is CO has an additive effect. Sitting in 70ppm CO at 12k for an hour would not be my idea of a good time. In our average spam cans, which are not exactly air tight, you should be seeing 0 or low single digits in level cruise. I've seen mine elevate in climbs, think that's an airflow issue. Also seen it high taxiing on a windy day downwind. When it gets cold, I do a heat on/off comparison as well.
 
Given the topic, may be pertinent to mention that pulse oximeters do not detect CO poisoning.
Your spo2 monitor will read erroneously high in cases of CO poisoning.

That is because the typical pulse oximeter detects the Oxygen molecule of the CO and doesn't know the difference. We do have ones at our Fire Department that can differentiate, but they aren't cheap.
 
Can you say something about this unit. Is the alarm loud enough? How long do the batteries last? At 0.1 amu it looks good.
The batteries will last several years....if you don't leave it on. I can't comment on the alarm. I doubt I'd hear it over my headset....but it is in my scan and I'd think I'd see it indicate.
 
I bought this same one and it goes through batteries like crazy. It never works because the batteries dies so easily. I shut it off after every flight too.

I have the Sensorcon that @Bill Jennings mentioned. I haven't shut it off since I bought it more than a year ago. Very solid unit
 
just ordered one form the discount link in the video description. It looked to be at least as good as any of the portables that come up in my search.

I found it interesting.... his point about being taught and thinking that it would be a linear and obvious chain of symptoms
+ his one brief mention about suspecting CO issues early on in the story
+ his asking the nurse to check for CO
They didn't really get into this in the interview...but there was something in the back of his mind making him aware of the problem leading up to it. It just wasn't so obvious to him it seems.

Anyway, as an aircraft renter, this is one of the many things that have been in the back of my mind regarding not being so fully aware of the aircraft and it's operational and maintenance histories. Arguably the CO detector isn't likely to be so needed in the summer when not using cabin heat....but you never know what might have not seemed like a pressing issue to someone else.
 
This story has inspired me to get a detector. I tested three detectors (including the sensorcon and the amazon one) and I found this detector as the best one for pilots:
https://www.sportys.com/pilotshop/carbon-monoxide-cockpit-monitor-17131.html

My testing video:


Not super scientific testing but gives you an idea how it actually performs.
Thanks for doing this comparison.. I was going to go with the Sensorcon but now not so sure. The Forensics unit looks nice but I worry about the lower alarm setting going off all of the time.
 
This story has inspired me to get a detector. I tested three detectors (including the sensorcon and the amazon one) and I found this detector as the best one for pilots:
https://www.sportys.com/pilotshop/carbon-monoxide-cockpit-monitor-17131.html
Not super scientific testing but gives you an idea how it actually performs.

Thank you!
Of the three, we know which reads the highest, but we do not actually know which was most accurate. In the intended application it is probably better to air on the side of caution, so even if the Tocsin is not the most accurate it will alert sooner.

All three units use electrochemical detection:
https://en.wikipedia.org/wiki/Carbon_monoxide_detector

Here is the operation manual for the Otis Instruments OI-315 TOCSIN3 CO detector:
https://www.brandtinst.com/Otis-Ins...-Rev.-2.0-from-v2.2-Web-Version-6172015_0.pdf

Ops manual for the Sensorcon:
https://cdn.shopify.com/s/files/1/0..._User_Manual_2018_V1.pdf?10968499652186516364

Ops manual for the Forensics unit:
https://cdn.shopify.com/s/files/1/3012/7408/files/instructions_v13.0.pdf?96
 
Check your exhaust system frequently.

Detection good, prevention better. :) I know that a sudden exhaust failure is possible, but more often it's a small crack that propagates over time and causes the issue.
 
How do you mount it? Velcro maybe?
This model has a fairly strong metal clip; I attach it to the side pocket in my cockpit where I store my checklist, charts, etc.
I don't think it needs to be in my field of view - the alarm is very loud; the whole idea is that you DON'T have to watch it, it'll get your attention if or when needed.

- Martin
 
Check your exhaust system frequently.

Detection good, prevention better. :) I know that a sudden exhaust failure is possible, but more often it's a small crack that propagates over time and causes the issue.

I did watch the informative video, lucky guy. I wanted to see the cause of his incapacitation, exhaust crack then leak. Maybe it was hidden, can’t see everything.
 
Thanks for doing this comparison.. I was going to go with the Sensorcon but now not so sure. The Forensics unit looks nice but I worry about the lower alarm setting going off all of the time.

also thanks from me for posting that.
I had already ordered the sensorcon when I saw it. At first I was a bit bummed

but then it dawned on me that there's a chance if I ordered the same units I could potentially get different results. In my limited experience with these cheap little detectors that aren't always the most reliable and repeatable.

I also had the same thought as Morgan regarding the possible nuisance alarms if one is just "too sensitive".

I didn't notice though, how do the alarm set points compare with these different users. I understand you saw different indicated readings but I wonder if there is also some difference in trigger points.....

Anyway, I appreciated your thorough review and especially the bit comparing their various suggested recalibration periods. Seems to imply that they aren't simply disposable after their 2 years (what I seem to read a lot regarding life spans of these things)
 
I've been using the TOCSIN 3 I picked up at sporty's for a few years. https://www.sportys.com/pilotshop/carbon-monoxide-cockpit-monitor-17131.html

I really like it and have only needed to replace the battery once after about 1-1 1/2 years. The beep alarm is loud enough I can hear it even with my LightSpeed Zulu 3's on and I keep it clipped to the seat belt down low where I can feel it vibrate the belt when it alerts as well. It gets tested when I do the run-up sometimes depending on the winds.

Whatever people choose, I'm glad people are using something. About 20 years ago in a Turbo Lance I had the little circle card go black quickly (exhaust stack issue on a camera plane) and if I didn't happen to glance at it, probably wouldn't be here now.
 
I agree about the little tabs. They're expensive, and they taste terrible. I don't really know how any medicine can prevent CO2 poisoning, but my CFI said to buy the pill, so I did.
 
Do I need one? My cabin heat does not come off an exhaust can. (it comes from compressed air exiting the turbo).
Ie what is the chance of (incapacitating) CO entering the cabin from temporary configuration changes or taxing with the door open or an ongoing exhaust leak that finds its way through the firewall?
 
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