We now have about 25 hours on our mono-wheel XS.
I am getting cabon monoxide levels of 60-100 ppm
in flight. The firewall is tight. The CO seems to be
coming in from behind the baggage bay.
When in flight, air exits the cabin through the control
slots in the tunnel, but enters the cabin from the
tail area when the baggage bay / fuel pump access
panel is lifted slightly.
Our guess is that the CO is from the exhaust pipe,
going under the port wing, then entering the port
side flap drive slot. With the tail at higher pressure
than the cabin, the CO can enter through many small
openings into the cabin. Lowering the pressure in
the tail cone would seem to help the problem, but
how?
Has anyone else experienced this problem?
If so, any suggestions?
BTW, we installed the AIM CO detector, recommended
in an article on the subject on AVWEB. This device
integrates CO levels over time, supposedly emulating
accumulation in the blood over time. Besides having
a digital readout of the current CO level, an audible alarm
may happen in a few minutes at high levels, or after
several hours (or even several flights) with moderate levels.
Terry Seaver
A135 / N135TD
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