Originally Posted by
djpil
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.
I'm sure the authors of that paper would be happy to talk to CASA if asked. Thanks for mentioning it to them. There is an unformatted copy on Coventry University's website here:
https://pure.coventry.ac.uk/ws/porta...82/Binder1.pdf
The trichotomy here is that there's training material (e..g. EASA licencing requirements), there's flight test advice (e.g. AC 23-8) and there's aerodynamic understanding (as for example found in Darrol's books). In a perfect world all would march neatly in step: the reality is somewhat different. As that 2014 paper showed also there's not necessarily a universal understanding of any of the three - EASA and the FAA continue to promulgate different stall recoveries, as a really obvious example.
I don't have a big issue with there being different definition of the crossover point between an incipient and a developed spin -but as variations exist, it's a really good idea to be precise with the definitions in use.
G