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CO detector / how much carbon monoxide is acceptable in the cockpit

Our “Sticker”, on the panel, darkened in flight, then cleared. We added a new one. Same result. Then they stayed black. We bought a bleeper, then a % reading + bleep at higher levels, device. With a draught coming in where the clamshell doors meet, head level readings were always safe. Readings varied according to where in the cockpit it was placed.
Eventually we found a hole in the exhaust behind a downpipe join.
The spot type was good at detecting low level CO over a long time, which is the cockpit danger. Maybe the high level, short time test was unfair.
I’ve posted YT videos where the bleeping is noticeable in the background.
(The triangle score from Tchaikovsky’s 1812 overture?)

Maoraigh
EGPE, United Kingdom

Aviathor wrote:

Keep in mind that you need to replace these electronic CO detectors on a regular basis, …

That depends on the type of sensor they use. I have a “home made” one which uses an “MO-9” heated semiconductor sensor which in theory has no lifetime limit. This type sensor on the other hand can degrade if left unpowered for longer periods.

EDDS - Stuttgart

what_next wrote:

I have a “home made” one which uses an “MO-9” heated semiconductor sensor which in theory has no lifetime limit. This type sensor on the other hand can degrade if left unpowered for longer periods.

Don’t expect years of service of these. They will degrade in performance in about 2 to 3 years. Some of them can be calibrated, but once you need to adjust, you will be lost, and will be out of tolerance again the next year. It’s a good idea to replace these sensors every 3 year or so.

JP-Avionics
EHMZ

With only 2 devices, how do we know the cheap chinese digital gauge is not over-reacting?

ESMK, Sweden

I bought the exact Chinese model from the video and tested it on the exhaust pipe of my car and in two airplanes. While the indications were prompt and plausible, the aural alert is by no means loud enough for airplane use, especially with an ANR headset.

So I returned it and bought this one (sorry, link in German):

http://www.avionik-zentrale.de/Kohlenmonoxyd-Warngeraet-als-Schluesselanhaenger-Akustisches-Warnsignal

Airplane test is still pending, but at least the beep is much louder and it is also smaller and lighter.

Friedrichshafen EDNY

With only 2 devices, how do we know the cheap chinese digital gauge is not over-reacting?

A very good point… however I find that my one (BW Gasalert, wasn’t cheap when I got it c. 2002) picks up the exhaust from a plane landing before me and shows about 20ppm It can also show a similar reading if you fly (in the TB20) at a high pitch attitude, as in a power-on stall practice.

So one tends to get occassional warnings…

Administrator
Shoreham EGKA, United Kingdom

@tschnell That is the device I am using for many years now, and I’m happy with it. The battery needs frequent replacement, but I ordered a bunch from Aliexpress so that is taken care off.

I’ve made two attempts to order the calibration kit but even inside the US to no avail. But it still seems accurate enough after ~5 years judging from the different planes in my club’s fleet and what values I’ve been seeing there.

The only negative is that I’m always being ridiculed by our chief pilot for owning a carbon monoxide detector, PLB and handheld radio. But I can live with that.

The battery in the BW one above lasts about 2 years. It used to last a year when I left it on all the time, which is not bad.

Administrator
Shoreham EGKA, United Kingdom

tschnell wrote:

I bought the exact Chinese model from the video and tested it on the exhaust pipe of my car and in two airplanes. While the indications were prompt and plausible, the aural alert is by no means loud enough for airplane use, especially with an ANR headset.

So I returned it and bought this one (sorry, link in German):

http://www.avionik-zentrale.de/Kohlenmonoxyd-Warngeraet-als-Schluesselanhaenger-Akustisches-Warnsignal

Airplane test is still pending, but at least the beep is much louder and it is also smaller and lighter.

Just checked the specs of the Pocket CO 300: alarm sound 82dB – highly unlikely that you will hear that, even without ANR.

My PAC5500 screams with 90dB, and even I have doubts whether it will get through. No test so far, as I do not like to have high CO levels in the cockpit…
I got an alarm last weekend with open doors when a DA40 started in front of us – but neither engine nor ANR in use…

That said, the PAC blinks + vibrates at the same time and is fixed in scan range.

Last Edited by ch.ess at 08 Mar 07:58
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EDM_, Germany

With only 2 devices, how do we know the cheap chinese digital gauge is not over-reacting?

Not sure about the devices of unknown origin, but the CO alarms we can buy at DIY shops here in Europe are at least certified to the appropriate safety standards, so even while oversensitivity won’t make them unsafe, they are at least supposed to undergo a reasonable kind of calibration.

LKBU (near Prague), Czech Republic
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