CO level in cabin

[Jinkers]

Hi All,

I bought one of those portable Honeywell CO detectors. It is constantly reading 35-40 ppm if the vents are closed. The alarm 1 setpoint is 35 ppm and it is going off constantly. Alarm 2 is set at 100 ppm

I discussed it with my mechanic and he didn't seem to think that this was unusual for a 50 yr old tube and fabric airplane. He has checked the exhaust and firewall and says that he doesn't see any problems.

I did some reading up on OSHA CO levels. The acceptable average CO level in the workplace is 50 ppm for 8 hours not to exceed 100 ppm at any time. I couldn't find anything in the FAR/AIM that listed specific allowable CO levels in the cockpit. I live at 5000 feet and regularly fly at 7-8k and frequently climb to 12k or so in the mountains. I don't know if OSHA's numbers had that in mind.

So does anyone know if 35-40 ppm is an unusual reading for a PA22? Does anyone have any insight into the physiological effects of these levels of CO at higher altitudes?

Thanks,

[Tripod]

I have no idea what is "normal" cabin CO for a TP, but here's an interesting link that might help you:

http://en.wikipedia.org/wiki/Carbon_monoxide_poisoning


-dave

[Stephen]

I've got the same CO moniter in my Pacer, generally it is well below 10 ppm, it occasionally will jump into the 30's to 40's during landings (slow flight). The area around the landing gear is very leaky and my doors are leaky.

[Steve Pierce]

I have had this issue in several Short winged Pipers. I had Dawley make me a longer tail pipe which really helped. Also look at the gear fairings and how well sealed up the belly is. I have also put a plate over the cabin heat box but that was mainly for heat leaking through in the summer. Make sure the firewall is well sealed. The biggest culprit I have seen is the exhaust entering from the belly, the longer tailpipe gets it out into the slip stream and away from the fuselage. You might try an extension as an experiment.

[Jinkers]

Good info gents

Is there an exhaust extension readily available for purchase or would this be something I would have to have fabricated?

I have the stock exhaust system. I know that there are aftermarket exhaust systems available, would any of these have an extended pipe? and do they really increase performance as advertised? Any one in particular that is best for the O320?

Thanks!

[Steve Pierce]

I have heard of peopl getting an extension at the auto parts store for testing. If that worked I would get a tail pipe made a little longer.

[Stephen]

I simply rolled a piece of steinless and had it welded onto my original tail pipe. Extending the tailpipe solved a previous problem of CO for me.

[Hillbilly]

I remember sometime back the fellas over at the MustangII builders e-list they were having great results with some sort of piccolo tube extension, and it had some other benefits as to belly oil and I think even exhaust scavenging. I dont know the manufacturer but I'll try to find out...standby (hard bank, rolling to the treeline...)

[Hillbilly]

This taken from a message posted at the Mustangaero e-group at yahoo...


"Wick's Aircraft sells them- they're called "Perforated Exhaust Muffler" or "Piccolo Tubes":
http://www.wicksaircraft.com/catalog/pr ... index.html
http://www.wicksaircraft.com/catalog/vi ... p?pid=4273 "


Hotel Bravo RTB ..out

[Jinkers]

Thanks for more great info.

I found a 6" extension at the local muffler shop I'm going to clamp on for testing. If that works I'll have to decide what the permanent solution is.