“So how much is too much? The US Occupational Safety and Health Administration (OSHA) uses 35 ppm as its lower limit, although it’s important to note that this is based on a time weighted average (TWA), taken over 8 hours. OSHA uses 200 ppm as a 5-minute sample ceiling, and 1500 ppm as an instantaneous limit.
In our experience, pilots should err on the side of caution. Certainly a concentration of 200 ppm should get your attention right away: turn off the heat, open the fresh air vents, and consider landing. It’s highly likely you have an exhaust leak. But pilots can also be impacted by much lower levels. Even 35 ppm, which could be caused by poor airflow or even the landing gear being down, can cause confusion, fatigue, and poor decision making if it persists for an hour. For that reason, we like units that alert at 35 or 50 ppm."
from the source here: Carbon monoxide – what pilots need to know
NCYankee wrote:
This is what I have: AV8 Aviation CO2 Moni
I’ve checked their website and it looks like they can ship to UK, cost of shipping to UK being about 32$ for one unit, which makes the total cost of the basic unit 171$. That seems quite acceptable, around the cost of one flight hour, give or take depending where you are based and what you fly of course.
“It has long been known that Pledge works fine on plexiglass.”
Agree, but check, there are different formulations. One is good, one is not. Check the aerosol info on the can
i have used a BW Gas Clip since about 2015 buying every 2 years. One can choose the lower alarm level and i choose the 35ppm initial warning. The higher level of 200 ppm is fixed. These BWClips are calibrated and not useable after 2 years so no danger in holding onto an uncalibrated piece of junk. The latest cost was £164 inc vat and delivery. Since 2015 I have been notified my Service team of two possible small CO leaks, initially dismissed, until i persisted and subsequently they were located.
I cannot see any reason to cut corners in buying a device not certified to this level, after all we are flying certified aircraft and the cost of owning such aircraft is far greater so as to make £164 practically nothing.
At 35ppm one will get the lower alarm activated sometimes in taxi, sometimes at t/o, sometimes during final, but never in the cruise (or you have got a real problem). The BWClip keeps a record of the running max value for the day. I have bought them from various suppliers in the UK. I think 3year BWClips are available.
The paper/card warning devices are to all intents completely useless.
NTSB today reported to be asking the FAA to mandate CO detectors in GA, the second time they’ve asked for this. Specifying a specific aviation CO monitor.
After shutting down yesterday I heard distinct beeping. My CO detector was saying goodbye after 2+ years of service. I have the BW Gasalert that needs replacement.
Good reason to resurrect this thread and make use of the excellent into here.
I’ve had my doubts about the volume of the BW. I don’t have an easy option to put a unit in my direct line of sight and rely on the aural warning. Have had some alerts but always on the ground, at stationary RPM. Not sure if I’d hear it in cruise..
This thread lead me to the following brand. I have two USB-ports on board, so the Model 6 seems perfect for me. I like the option to connect to my phone/headset. Available in the EU for € 169 plus shipping. 7 years lifetime. Let’s hope I can buy 2 or even 3 more of these during my own lifetime..
Seems like a fairly new product. Any experiences here?
https://www.aviationconsumer.com/accessories/co-monitors-aithre-a-top-pick/
https://www.air-store.eu/Aithre-Shield-USB-60-Portables-CO-Warngeraet-mit-App-Schnittstelle*Bold*
IMHO the answer is “zero”.
Apart from specific cases like CO getting sucked in when you land, or the CO from the plane which landed before you being sucked in via the heater air intake, you should not see any CO reading at all.
I have had my BW Gasalert for over 20 years. Cost about £200.
Peter wrote:
IMHO the answer is “zero”.
Agree completely. I see CO from time to time doing a run-up if the wind is blowing the “right” way. If I ever see CO any other time, I will land and inspect the exhaust system.
I don’t think zero indicated CO level is achievable all the time, it all depends how sensitive your sensor is and the external environment. Mine would trigger a “yellow level” warning when flying low enough above an industrial chimney. First noticed that when doing t&g’s followed by tight circuits over some coal mine. Warning light would repeatedly light up for maybe 10 seconds over the same spot. Over time, I just learned to ignore the “yellow level” warning when there is a reasonable chance that the indication is triggered by air coming from outside.
I don‘t think that changes the answer to the question. It just means any reading needs determination of the cause and associated action, which might just be continued flight away from the smokestack or in this case coal mine.
