CO and the Lightspeed DZ

[zehutiman]

I’ve been flying my Mooney for about 3 months, and I use the Lightspeed DZ headset that has CO detection.  Yesterday (March 21), I got my first CO alert while using the headset.  It coincided with me turning on a little bit of heat — just a crack.  I took a look at the headset app and it showed CO levels during previous flights.  You can definitely see a spike in CO level when I turned the heat on;  then I turned it off and opened all the fresh air vents.  I’m curious if there are other Lightspeed users who can compare their CO profiles to mine.  Btw, I think the headset alerts a caution between 10-50 ppm, and a warning above 50 ppm?  I’m not certain, though.  Sorry, the screen shots are out of order.

 

Edited March 22, 2023 by zehutiman

[GeeBee]

The most I see with the heat on in my R is 2ppm. So you definitely have some burnt hydrocarbons coming in somewhere. '

PM sent by the way.

[N201MKTurbo]

The CO may not be coming from your plane. You didn't mention what you were doing when you turned the heat on. Were you flying or on the ground? When you turn the heat on, you are allowing outside air into the cabin. I get the highest readings in the runup area because I'm breathing exhaust from the other planes.

I know most airports aren't like ours where there may be 5 (or more) airplanes running up in a small runup area.

If it was during flight, an inspection of the exhaust and heater is in order.

[zehutiman]

46 minutes ago, N201MKTurbo said:

The CO may not be coming from your plane. You didn't mention what you were doing when you turned the heat on. Were you flying or on the ground?

Yesterday was definitely during flight, but to your point, I’ll have to pay closer attention to the actual times in flight — some of the timeframes shown in the screenshots extend after landing, maybe even up to an hour.

Edited March 22, 2023 by zehutiman

[Ragsf15e]

The levels aren’t very high, so that’s good, but if they are definitely correlated to opening the heat, that’s bad.  Even with low levels, I’d check that out.

I show zero ppm in flight even with the heat on.  On the ground, I see 10-20 depending on winds and which way I’m pointing.

Some people see a little in climb but then settle down to zero in cruise.  You might want to see exactly where/when yours is climbing.

[DXB]

CO can get in the cockpit various ways, but unfortunately any increase in CO that has precise temporal correlation with opening the heat means there is an exhaust leak from the muffler into the heat shroud.  In this case the leak is miniscule and thus not an immediate threat when you turn on the heat, but that can change very quickly.  I would suggest inspecting the muffler ASAP.

[Fly Boomer]

3 hours ago, zehutiman said:

 I took a look at the headset app and it showed CO levels during previous flights.  You can definitely see a spike in CO level when I turned the heat on;  then I turned it off and opened all the fresh air vents.

Picture number 5 (from top) shows that at about 14:40, temperature suddenly plunges down to 60, and CO spikes.  That seems to be opposite to the heat=CO behavior.

[zehutiman]

55 minutes ago, Fly Boomer said:

Picture number 5 (from top) shows that at about 14:40, temperature suddenly plunges down to 60, and CO spikes.  That seems to be opposite to the heat=CO behavior.

I think this correlates to me turning off the heat and opening all the fresh air vents — the temperature dropped due to all the vents being opened.