That was my inner voice screaming. My actual voice asking, What the *&^%* is going on? at least three times. It was a sudden, instantaneous event. One moment, I was trundling along in my Comanche 250 climbing slowly eastward over the Sierras, looking out at clear blue skies as the autopilot dutifully tracked the GPS toward my destination. Then, bam! The cabin filled with an acrid-smelling cloud. I could not see the instrument panel.
A pilot experienced a sudden, acrid smoke-filled cabin during a flight, obscuring vision and causing initial confusion.
The "smoke" was discovered to be yellow powder from an accidentally discharged dry-powder fire extinguisher, which had lost its retaining pin.
The incident highlighted the critical first step of opening vents for fresh air and visibility, and demonstrated why dry-powder extinguishers are not recommended for aircraft due to the mess and vision impairment they cause.