Vixxen

Thank you for this. The coolant leak could well have been the issue. I've just realised that during the DI before we took off, my wife had taken off the coolant cap (cold) and there was a tiny bit of pressure which led to some spillage. I thought we had cleaned it up but in all likelihood we missed some. Thinking back, the smell was likely coolant. Thanks everyone for your input.

I've a CO Gas Alarm as well as an inbuilt detector on our Lightspeed headsets. Neither of those alarmed. I've used the heater a handful of times before but probably not as long as this time, maybe an hour or more. The "volatiles" you mention could be the reason or maybe as someone else mentioned, maybe coolant/antifreeze though I could not see any evidence of a leak. Thanks for your reply. Cheers

Recent 4-5 hour trip in my 3 year old A32 Aeroprakt Vixxen. About two hours into trip we noticed a strange smell in cabin. Not pungent or irritating but couldn't be cleared by venting the cabin. Had the heater on at that stage so turned it off as well as some electrics and it reduced. CO2 monitor didn't activate. Diverted to a nearby strip, pulled the cowl off and had a good look where we could. Did we imagine it? Took off and flew another 3-4 hours that day with no further issues but kept heater off. Next day flew home, tried heater again on low and had no issues. Any thoughts?