Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Flight Crew Multiengine; Flight Crew Private; Flight Crew Instrument
Flight Crew Last 90 Days 15; Flight Crew Total 205; Flight Crew Type 15
Situational Awareness; Confusion; Physiological - Other
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Flight Deck / Cabin / Aircraft Event Illness / Injury
Flight Crew Took Evasive Action; Flight Crew Diverted
Environment - Non Weather Related
I was climbing out of approximately 6;500 feet when I started to notice the smell of a wildfire. I surveyed the area and did not see any wildfires in the immediate vicinity. A short time later; I started recognizing the symptoms of hypoxia; namely confusion; short-term memory loss; shortness of breath and blurred vision. At this point; we were nearing our assigned altitude of 9;000 MSL. I immediately requested lower and was assigned 7;000. During our descent; I started planning a diversion to a VFR field. It was at this point that I should have notified ATC of my symptoms; but for reasons that are still unknown; I did not inform them of the exact circumstances surrounding my diversion. NorCal Approach and Oakland Center were incredibly accommodating with my requests for lower altitude. The flight ended uneventfully at [an alternate airport] and we continued the rest of the journey the following day.During my debrief; I hypothesized that the onset of hypoxia was accelerated by the ambient smoke in the air. I also hypothesized that given the wind direction; this smoke was likely from the many wildfires burning in the [mountains]. Perhaps a wildfire area should be added to the standard weather briefing. For pilots of non-pressurized aircraft; smoke in the air lowers the altitude where pilots will start suffering from hypoxia. I realize that the standard weather briefing is extremely lengthy as it is; but hypoxia is a serious issue and I think everything should be done to protect pilots from it.
A general aviation pilot reported symptoms of hypoxia due to smoke from widespread fires in Northern California led to a diversion.