Amateur/Home Built/Experimental
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Flight Crew Total 2000
Situational Awareness
Conflict NMAC; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Human Factors
While flying direct from HZL VOR to EMI VOR in level cruise at 6500 feet; a Turbo Porter (or similar) aircraft plummeted from an altitude above me in a fully-developed spin; and continued in that spin to an altitude below me; at a clock face position of about 2:00 to 3:00 to my aircraft (his relative position changed as I passed). I estimated his distance this morning; using a line of backed-up traffic for comparison. Finding a car that was about the same distance from me as the Porter; then counting the number of cars between us; I was surprised that the distance was just fifteen cars; or about 240 feet! The Porter aircraft was close enough that I saw his paint job in detail.The Porter aircraft was being flown in a manner that precluded his ability to 'see and avoid.' The fact that he was riding that spin for several thousands of feet vertically also made it difficult for other aircraft such as mine to see and avoid him; pilots are not typically looking for traffic which is falling vertically from the sky. I suspect that this aircraft was spinning the aircraft down in order to minimize the time spent in his descent. This practice is inherently unsafe and should not be permissible in unrestricted airspace. It was only by sheer luck that a catastrophic collision was avoided this time.
Glasair pilot reported an NMAC with a spinning aircraft that descended rapidly through his altitude.