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Incipient Spins

Old 1st Dec 2019, 14:48
  #21 (permalink)  
 
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Originally Posted by djpil View Post
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
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Old 1st Dec 2019, 21:28
  #22 (permalink)  
 
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IIRC the reason we stopped teaching “spinning” was that more people were killing themselves spin training than were actually killing themselves through inadvertent entry.

Again, I can’t help thinking that this is all a little overkill. I understand that something needs to be done with fundamental “basic pilotage” but surely the more appropriate response is awareness/avoidance rather than recovery?

I make sure that all my FI candidates are fully aware of the dangers of spinning (we do several fully developed) and pray that the lessons are then passed on to their students.

Finally, I would disagree that the 152 is a good spin trainer. All those that I have had the pleasure to fly only require you think of relaxing pro-spin and they’re flying again. Surely, if the point of all this is recovery (with the correct technique) then perhaps we need something that requires correct recovery inputs every time.... or are we back to point 1 above again?
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Old 1st Dec 2019, 23:26
  #23 (permalink)  
 
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That's the reason we stopped spinning in the PPL course, and I'm not sure there's any strong evidence we should reverse that either.

The routine use of barely aerobatic aeroplanes in instructor courses, without use of parachutes, is hardly setting a good example. The lack of spinning in CPL courses on the other hand is even less defensible, so the inclusion of UPRT in the integrated CPL, done well (which presumably means including incipient spins), has to be a step in the right direction. But FFS, not in C152s - there are aeroplanes actually designed for this sort of flying, and they usually fly with parachutes fitted as well.

G
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Old 2nd Dec 2019, 00:41
  #24 (permalink)  
 
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Annex I to ED Decision 2019/005/R
‘AMC and GM to Part-FCL — Issue 1, Amendment 7’

‘Incipient spin’ refers to a transient flight condition in the post-stall regime where an initial, uncommanded roll in excess of 45° has resulted from yaw asymmetry during a stall and which, if recovery action is not taken, will lead rapidly to a developing spin. Prompt recovery during this Annex I to ED Decision 2019/005/R Page 7 of 50 incipient spin stage will normally result in an overall heading change, from pre-stall conditions, of not more than 180°.

‘Developing spin’ refers to a flight condition in the post-stall regime where the aeroplane exhibits abnormal, but varying, rates of yaw and roll, together with changing pitch attitude, following an incipient spin but before the establishment of a developed spin. A developing spin follows an unrecovered incipient spin and will usually persist, in the absence of any recovery action, until a developed spin ensues. ‘Developed spin’ refers to a flight condition in the post-stall regime where the aeroplane has achieved approximately constant pitch attitude, yaw rate and roll rate on a descending flight path. In transition from a stall with significant, persistent yaw, with no recovery action, to attaining a developed spin, the aeroplane is likely to have rolled through at least 540°.

EASA can't help dabbling. They leave one losing the will to live.

Last edited by Fl1ingfrog; 2nd Dec 2019 at 01:01.
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Old 2nd Dec 2019, 07:57
  #25 (permalink)  
 
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And I'll bet that if you were able to follow the trail, you'll find virtually no rigorous research behind EASA's position there - just opinion.

G
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Old 4th Dec 2019, 09:59
  #26 (permalink)  
 
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EASA.... you've got to love them...their "bureaucratese" language and the length of their sentences reach a level of inimaginable obscure sophistication ....Why do you need to make things easy when you can make them difficult...It s totally hilarious but unfortunately for the everyday user it's...sad

The only way to understand how spin dynamics work, is to get a qualified instructor and proper aircraft and go practice, in stages, so as to develop "muscle memory", based on proper techniques and reflexes. That is how the human being functions.

Aviation is the only field where adressing complex problems (Spinning) with "easy" solutions (Training) is replaced by referring to the SOP's.
It's like asking a 5 year old kid to go figure the way to use a playstation by reading the instructions online.......

Last edited by markkal; 4th Dec 2019 at 10:11.
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Old 6th Dec 2019, 17:24
  #27 (permalink)  
 
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Originally Posted by Fl1ingfrog View Post
Annex I to ED Decision 2019/005/R
‘AMC and GM to Part-FCL — Issue 1, Amendment 7’

‘Incipient spin’ refers to a transient flight condition in the post-stall regime where an initial, uncommanded roll in excess of 45° has resulted from yaw asymmetry during a stall and which, if recovery action is not taken, will lead rapidly to a developing spin. Prompt recovery during this Annex I to ED Decision 2019/005/R Page 7 of 50 incipient spin stage will normally result in an overall heading change, from pre-stall conditions, of not more than 180°.

‘Developing spin’ refers to a flight condition in the post-stall regime where the aeroplane exhibits abnormal, but varying, rates of yaw and roll, together with changing pitch attitude, following an incipient spin but before the establishment of a developed spin. A developing spin follows an unrecovered incipient spin and will usually persist, in the absence of any recovery action, until a developed spin ensues. ‘Developed spin’ refers to a flight condition in the post-stall regime where the aeroplane has achieved approximately constant pitch attitude, yaw rate and roll rate on a descending flight path. In transition from a stall with significant, persistent yaw, with no recovery action, to attaining a developed spin, the aeroplane is likely to have rolled through at least 540°.

EASA can't help dabbling. They leave one losing the will to live.
And any attempt to try and define these states by referring to a specific number (180 degrees, 540 degrees) IMHO does far more harm than good. There MAY be a specific aeroplane that hits these specific numbers, but it varies massively from aircraft to aircraft.
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