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-   -   Incipient Spin Recovery (https://www.pprune.org/flying-instructors-examiners/545871-incipient-spin-recovery.html)

BEagle 19th Aug 2014 07:27

Hi Dan, you foreign devil!

I found my old Spinning 2 notes - basically brace the control column and rudder central until the buffet / undemanded roll stops. If nose high, full throttle, if nose low, idle power. Then roll to nearest horizon, level wings and recover from the descent.

I didn't care much for the 'nose high / nose low' assessment, so I said 'if IAS changing rapidly, move throttle in opposite sense - otherwise leave it where it is'.

During CFS time, a colleague and I did a 'giveback' session of Spinning 2 - his demo. of 'full spin from manoeuvre' was interesting - pull into the vertical from about 120KIAS, apply full pro-spin and close the throttle....:uhoh: The poor little aeroplane went nuts as I sat there playing Bloggs and he tried to sort out the recovery.....:eek:

ShyTorque 19th Aug 2014 07:51

Dan, Beagle, thanks - that confirms my reply about RAF training.

One thing to remember is that an incipient spin can occur in any attitude, such as during aerobatics. Talk of heading change and wing drop is more relevant to straight and level stall/spin entry.

Civilian students, at least at PPL level, and probably at CPL level, are unlikely to see the former unless they are being taught beyond the normal syllabus.

The Bulldog "spin off manoeuvre" was demonstrated to UAS students. IIRC, this was done by applying pro spin control during a loop, at least, that is what I remember doing.

I used to enjoy this part of the syllabus, most students didn't... :E

Arm out the window 19th Aug 2014 08:18

RAAF training for incipient spin in the PC-9 (defined as two turns from application of pro-spin controls as I recall, and probably rightly so - the first couple were flopping about until the aircraft established itself in a 'proper' nose down spin) called for throttle idle and controls central, whereupon it would quickly recover.

Fully developed spin recovery was confirm idle, identify direction of spin (turn needle), apply and hold full opposite rudder with control column central until spin stopped, centralise rudder and recover from the dive.

Incipient spin training is useful in my opinion so that when we stuff something up (eg mishandled aeros), feel buffet and notice the onset of autorotation, the instinct is there to close throttle and centralise. Then if it develops into something more fully developed, the flight manual recovery for the aircraft in question is the next port of call.

So - incipient spin - close to stall, buffet, uncommanded roll - go for the incipient spin recovery.

mad_jock 19th Aug 2014 09:02

I think we need to define what level of pilot we are teaching this to.

PPL

Aero

CPL

Instrumet

What flavour.

PLL I would teach them not to get near it and to recover as per normal stall recovery.

What you aero boys/girls do I have no idea.

Genghis the Engineer 19th Aug 2014 09:52


Originally Posted by Dan Winterland (Post 8614767)
It's type specific. On the Chipmunk and Bulldog, the recovery was to centrralize the controls only. The Tucano, centralize and idle thrust. As the Tucano prop does 2000rpm in flight regardless of the throttle position, there are no gyroscopic force changes to worry about.

The RAF defined an incipient spin as buffet with undemanded roll, the combination of the two should warn you that you need to centralise. As the training was to teach pilots who would fly aircraft where this combination was a bad thing (Harrier, Jaguar, Buccaneer, Phantom Lightning and to a lesser extent the Tornado) this was good advice and the main emphasis in the training. Trainee pilots would get lots and lots of practice so that the recovery would be instinctive.

The RAF define the change from the incipint spin to the full spin as when the aerodynamic and inertial forces balance each other out. That sounded like a good explanation to me.

Thanks for that correction - most of my military LOC work was with the Tucano, which would explain my slightly incomplete recollection.

Darrol Stinton, who was an instructor at ETPS and wrote a few rather good books on aircraft design and flight testing, used a similar definition for incipient then fully developed spin, but reckoned that was normally about the first 6 turns. By that definition (which holds some reasonable water when you look at instrumentation data from a few spinning-instrumented research aeroplanes) most of us have never seen a fully developed spin.

G

ShyTorque 19th Aug 2014 14:26

Mad Jock, surely an incipient spin is the same, irrespective of who is at the controls.

The correct teaching should surely be to recognise and efficiently recover from any attitude, rather than merely to complete a set piece manoeuvre from an ideal straight and level entry because a syllabus requires a box to be ticked. Pilots don't generally enter an incipient spin from S&L, but from a botched manoeuvre.

The UK PPL syllabus isn't the same since spinning was no longer required, pilots still make handling errors such as low speed/ too high a rate of bank on the finals turn and still need to know what to do about them.

mad_jock 19th Aug 2014 14:44

It is and it isn't.

For PPL level the deal is to stop them getting into that position anyway.

Most PPL and CPL's these days won't have a clue what you guys are on about anyway.

FI's will have had to demonstrate one spin in their test but that's about it.

Genghis the Engineer 19th Aug 2014 15:00

I agree MJ, and worse I gather that under EASA the spin recovery has now been quietly removed from the skill test.

I think that removing spinning from the PPL syllabus was sensible, but complete removal is not. I think, myself, that it should be in the CPL syllabus.

G

mad_jock 19th Aug 2014 15:15

Well removing it from the FIC is a bit daft cause those buggers will get you into unusual attitudes in a blink of an eye.

Mind you I never anyone succeed getting me into a spin. Close a few times

Big Pistons Forever 19th Aug 2014 15:54

I think the most practical deliniation between an incipient spin and a spin is

Incipient spin. Stall recovery actions will allow control to be regained. That is stick forward, full power, control the yaw with rudder

Spin. A stall recovery will not work because the rotation must be stopped before forward stick can be applied and the power must be reduced to idle.

For all common trainers you need to get well into the second turn before simply applying forward stick will not effect a recovery.

Canada does not have spins on the flight test but the instructor is required to demonstrate one prior to solo. I always do one just prior to going to the circuit and do it by setting up a too slow skidding base to final turn scenario (at altitude in the practice area of course)

Outside of aerobatic training the spin is not a manoever, it is the consequence of screwing up, badly. I strongly feel that if it is going to be demonstrated as part of PPL /CPL/type training than it should be presented not as "today we are going to learn how to do a spin" but rather "this is what will happen if you allow the aircraft to inadvertently stall (BAD !) and then don't control any yaw that develops (WORSE !).

The best way to do this is to present the student with the common stall/spin scenarios. Success is not recovering from the spin it is recognizing and avoiding entering the incipient spin in the first place.

G-F0RC3 19th Aug 2014 15:55

I wasn't required to do spin recovery during my PPL training (a couple of years ago now). However, I made a point of learning what control manipulations would be required to recover from one in the aircraft I was flying in case I needed them. It just seems like common sense to learn these in my opinion. :)

Speed Twelve 20th Aug 2014 21:24

Current UK military training for the Tutor is still as Beags, Dan etc have mentioned above. The symptom of an incipient spin is undemanded roll, centralise control column and rudder, leave the throttle, then recover from the resulting UP as required.

There's only the one drill, keeps it simple. Works every time. I agree that in the average Cessna, Piper etc you'd have to be pretty ham-fisted to end-up with undemanded roll in normal civilian flying. I agree the Firefly M used to flick like a good 'un if you pulled through the heavy buffet.

Are visual UP recoveries taught on the PPL or CPL course out of interest?

The Tutor Standard Stall Recovery incidentally doesn't involve the use of rudder either, other than to prevent yaw when selecting full power during the recovery itself and to balance if using aileron to level the wings after the buffet stops.

Genghis the Engineer 20th Aug 2014 22:08


Are visual UP recoveries taught on the PPL or CPL course out of interest?
Yes, it's called "recovery from unusual attitudes".

This is an American site but covers the UK teaching fairly well in IMC, pretty obviously in VMC it's the same using the visual horizon as reference.

Technique: Turns around a point - Flight Training

G

Speed Twelve 20th Aug 2014 22:18

Cheers Genghis, but that article covers UP recovery on instruments, standard for all instrument-rated pilots as you know.

I was wondering if civilian pilots were taught Unusual Position recovery using visual attitude techniques i.e. to cover loss of control in VMC, turbulence upset, disorientation etc. Spiral descent recovery I seem to remember being in the syllabus, it's a lonnnnnng time since I've trained civilian students.

Genghis the Engineer 20th Aug 2014 22:49

Oh yes, sorry.

The bulk of training at PPL level is stall avoidance and recovery. Spiral dive recovery is there, but much more emphasised in the NPPL(M) as it's a significant issue particularly in flexwings which can lock into the SD unless actively recovered, than in any "heavier" licence.

UA recovery is in the CPL - the VFR qualification - flown under the hood both full and partial panel as part of the IF component of that.

G

Speed Twelve 20th Aug 2014 22:54

Thanks Genghis.

Is the issue with flexwings due to the wing locking into a certain position due to aero loads and therefore having to be manhandled into a recovery position?

Genghis the Engineer 20th Aug 2014 23:10

Good question. I *think* it's because the very high directional stability of the highly swept delta wing, which makes it effectively impossible to spin, allows the wing, once a turn has developed, to continuously weathercock into the sideslip component of the unbalanced turn, and then the fact of the tilted lift vector, causes the accelerating rate of descent. Probably.

Recovery is easy, reacting against the trike, just place the control bar parallel with the visual horizon (well, easy to understand, but can require quite a lot of physical effort). But without that, the aircraft just maintains an accelerating and tightening turn, which presumably would result in either structural failure or ground impact.

I have played some years ago with significant rolling inputs at the point of stall in a flexwing to see what would happen. The rolling departure feels for maybe a quarter of a turn rather like a 3-axis incipient spin, but rapidly speed builds and it has clearly become a spiral dive, which then requires the standard recovery.

G

Speed Twelve 20th Aug 2014 23:24

Interesting. Anything that requires you to push away to pitch up is a black art to me!

dobbin1 21st Aug 2014 07:17

The EASA syllabus defines incipient spin as a stall with wing drop :-


(xiv) Exercise 11: Spin avoidance:
(A) safety checks;
(B) stalling and recovery at the incipient spin stage (stall with excessive wing drop, about 45°);
(C) instructor induced distractions during the stall.
I do most of my training in DA20 A1 Katanas, where it is quite easy to provoke a wing drop with a small nudge on the rudder, especially when there is some power applied. The recovery is standard stall recovery, full power, stick centrally forward and enough rudder to prevent the nose yawing toward the ground. Too much rudder and the wing drop will go the other way. I generally only do this once with my students, just until I can feel them adding the top rudder to stop the yaw when the wing drops. I have never got into a full spin doing this.

Some students want to experience full spins. If so, I teach them spin recoveries in our Firefly where we can wear parachutes and have a jettisonable canopy. I have spun the Katana alone wearing a parachute but it was very uncomfortable.

nick14 21st Aug 2014 07:23

Surely we would always teach to lead with lowering the angle of attack first not power?


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