"Montblack" wrote

I know many planes are leaky ...but if you do have a somewhat tight
cockpit, would a (small) fresh air feed, slightly pressurizing the cabin
(perhaps with a small computer type fan), be good insurance against CO gas
intrusion?

Somewhat tight is the key phrase. I don't think most are tight enough for a
muffin fan to be able to create positive pressure.

Add to that, fan blade type fans are very, very poor at creating pressure.
Squirrel cage blowers are used where pressure is needed. That is why house
air handlers (furnaces) have squirrel cage blowers, as do heater blowers in
cars.

Still, a fresh air blower will not help where the cause of the CO is a
cracked heat exchanger. (muff)

The other problems are fixed by sealing off the leaks, especially in low
pressure areas, but you knew that.
--
Jim in NC