cjohngraham
Member
I have been noticing an exhaust smell in the cockpit of my -7A. I borrowed an electronic CO detector with a digital readout and put it various places around the cockpit. The CO levels were well below the 35-50 ppm range considered the maximum acceptable by various agencies, e.g. 10-20 ppm on the right seat, 12 ppm on the floor, and 18-27 in the baggage area. With the cabin heat on and the detector near the cockpit floor, the reading decreased, so that is not the issue. Since the levels were highest in the baggage area, I suspect the CO is getting in through the flap actuator penetration. Levels rise a bit at slower airspeed/RPM, but not a lot.
The -7A (at least mine) has a negative pressure inside the cockpit relative to the outside, which was evident during Phase 1 when we had a sizable oil leak that got sucked from the belly of the plane into the fuselage (plane is unpainted). So I think that's why the CO is getting in.
Ideas/suggestions on fixing this? The plane's been flying over two years, and i think the reason it's just become noticeable (other than my sensitive smeller) is that I reduced some outside air leaks that were probably diluting the CO that was always there.
And yes, I do have my own electronic CO detector in the cockpit but it doesn't have a digital readout.
The -7A (at least mine) has a negative pressure inside the cockpit relative to the outside, which was evident during Phase 1 when we had a sizable oil leak that got sucked from the belly of the plane into the fuselage (plane is unpainted). So I think that's why the CO is getting in.
Ideas/suggestions on fixing this? The plane's been flying over two years, and i think the reason it's just become noticeable (other than my sensitive smeller) is that I reduced some outside air leaks that were probably diluting the CO that was always there.
And yes, I do have my own electronic CO detector in the cockpit but it doesn't have a digital readout.