Originally Posted by
Genghis the Engineer
The Late Darrol Stinton, who I knew well and worked with maintained that the incipient stage was the first 5-6 turns, and there are good data to back him up.
Personally I think it's until the direction of the spin is clearly established. We had some good arguments about that.
Either way, we need some clear definitions that I don't think are currently in universal use.
Per my prior post, EASA is quite specific as to what they want for an incipient spin in their advanced UPRT.
CASA has fairly clear explanations of incipient spin exercises in their Flight Instructor Manual chapter on spinning and, as described, require an intentional entry to a spin.
FAA AC 23-8C simply states "A spin is a sustained autorotation at angles-of-attack above stall."
I'm only interested in the notion of what an incipient spin is unless mandated by EASA, CASA etc. (The AC goes on "the fully developed spin is attained when the trajectory has become vertical and the spin characteristics are approximately repeatable from turn to turn. Some airplanes can autorotate for several turns, repeating the body motions at some interval, and never stabilize. Most airplanes will not attain a fully developed spin in one turn.")
Incidentally, I like the paper in the May 2014 Aeronautical Journal "Evaluating a set of stall recovery actions for single engine light aeroplanes" - I pointed CASA to this to consider the "Questions for Regulatory Authorities" - the link I had to this doesn't work.