Supersonic wrote:
I chose the second one…
Thanks Supersonic. I agree with your logic 
I have the earlier version of one of these and would recommend it.
You can definitely hear it even with ANR.
You just have to remember, when saying to the P2 guy “I’ve checked everything…..why is this god dammed aeroplane still beeping at me!!!”
That you may not have checked everything!
It was just out of annual and the reading was quite low. Took him 5 more minutes to find it though. Next time will be instant.
It’s just slightly out of sight from me, so the beeper is important.
My experience since last post in 2017…
PAC5500 reliably shows minor concentrations on screen, e.g. a crossing plane at a larger airport sends the concentration up to below warning levels. A starting YAK or T25 in front does trigger an alert ;-)
In winter during steep climbs I can get an alert (2x) which is not heating related but something to do with airflow through the gear ? Normalizes quickly in cruise.
And yes, i notice the alert easily and clearly through an ANR ! But it is with 90dB (per manual) at the high end of the range.
After changing a dead battery myself the device demands a calibration (symbol on screen) but still works perfectly – as per above, all the same. So I havent done anything yet.
Happy so far. I paid only about half, mine came out of lab surplus with low hours.
Now the proud owner of a BW Clip CO detector, I was disturbed to find the ‘peak’ reading alarm going off whilst trundling along the taxiway at Newquay at the weekend. Thankfully this stopped immediately once airborne – is this normal? I assume the lack of fresh air in the cockpit on a hot day doesn’t help.
jgmusic wrote:
Now the proud owner of a BW Clip CO detector, I was disturbed to find the ‘peak’ reading alarm going off whilst trundling along the taxiway at Newquay at the weekend.
Depending on the type I sometimes find that exhaust gases are blown into the cockpit through the vents in the canopy. Did you have any open?
Yes it is easy for wind to blow the exhaust into the cockpit – presumably via some open air vents.
Also, if there is little or no wind, it is normal to get a warning when landing, from exhaust gas of a previously landed aircraft.
Also you can get it going off when practicing slow flight. The high AoA can direct the exhaust up at the cockpit vent(s).
Peter wrote:
Yes it is easy for wind to blow the exhaust into the cockpit – presumably via some open air vents.
Aha, holding in position with a strong crosswind on the nose would have explained it then
Peter wrote:
Also, if there is little or no wind, it is normal to get a warning when landing, from exhaust gas of a previously landed aircraft.
An enormous military aircraft (sorry, I don’t know the type) had just landed ahead, which might also have explained it.
So the lesson is to close vents in these situations? It just shows how much more sensitive these professional models are. I’ve been oblivious of all this up until now with my cheap old FireAngel detector.
jgmusic wrote:
I was disturbed to find the ‘peak’ reading alarm going off whilst trundling along the taxiway at Newquay at the weekend
Happened to me twice in nil winds while on the ground, apparently mixture plays an important role, so in theory you can use it to find peak EGT and the right FF 
I would just open door/window while taxying, but I am not sure if it make it good or worse depending on airflow?
Ibra wrote:
so in theory you can use it to find peak EGT and the right FF
Oh, there’s a thought!
Ibra wrote:
apparently mixture plays an important role
Yes, rich mixtures make more CO.
