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In other words, after some training, is it possible to recovery a spin solely by relying on instruments?

If using a vacuum-pump traditional attitude indicator, I assume the answer is no, since there are limitations for its pitch and bank indication. What about an AHRS-based attitude indicator? Is it capable of matching 360° attitude changes in all directions, and catching up (without delay) with fast rolls? Can it filter out vibration well enough, so that a pilot is able to perform a spin recovery maneuver?

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    $\begingroup$ Given enough altitude, some aircraft will recover without pilot control inputs. Aircraft like the cirrus the recovery procedure is to pull the chute.A lot of being able to recover or not depends on skill and altitude. $\endgroup$ – Ron Beyer Apr 29 '16 at 11:17
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    $\begingroup$ In general though I don't think its possible unless you break out of IMC with 5000+ feet of altitude to spare. You are going to have bad spatial disorientation and not be able to trust the instruments. The chances of recovering from a spin while still in IMC are statistically close to zero. $\endgroup$ – Ron Beyer Apr 29 '16 at 13:16
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    $\begingroup$ @RonBeyer The Mueller/Beggs spin recovery technique (assuming it works in your aircraft) will recover just fine in IMC. $\endgroup$ – Dan Pichelman Apr 29 '16 at 13:47
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    $\begingroup$ @DanPichelman I'm not suggesting that normal spin recovery techniques wouldn't work in IMC, what I'm saying is that your spatial disorientation and brain may not allow it. That is why a Graveyard Spiral is such a deadly thing. You have no visual references so even recognizing that you are in a spin will be difficult. $\endgroup$ – Ron Beyer Apr 29 '16 at 13:54
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    $\begingroup$ I, for one, would like to do spin recover under the hood with a CFI $\endgroup$ – rbp Apr 29 '16 at 18:12
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I do not want to speak for civilian training here, and I do know that each aircraft has its own set of emergency procedures. Those procedures will depend upon the instrumentation that you have available to you. In my case I had full IFR instrumentation with a state of the art inertial navigation system. Spin recovery should be in the set of immediate action emergency procedures that you have memorized, and you should be able to perform them in your sleep. Can you recover from a spin while in IMC? Most definitely, and I speak from experience.

I flew high performance tactical jets for the US Navy. This included the T2, the A4, and the A7E. We only did spin recovery training in the T2. It was a lot of fun. High performance jets are often flying on the edge of their performance envelope. Consider air combat maneuvering where you can easily find yourself in uncontrolled flight, departing the aircraft in a high-g turn, or even nose high at 0 airspeed. I was told it was quite difficult to spin the A7E, which is what I flew in the fleet.

In the Navy we were trained never to look out the cockpit if we thought we were in a spin. There was unusual attitude recovery training under the hood, as well as learning how to recover from departed flight (approach turn stall), and spins. It was drilled into us from day one to come in to your instruments for spin recovery. It would not have mattered to me whether I was IFR or VFR, the decision on recovery was strictly based on instruments. We were told if you look outside the cockpit during a spin you might misinterpret the visual cues, and while not actually in a spin, place the aircraft in one by applying spin recovery techniques. The procedures were something like:

  1. Altitude: below 10,000 feet eject
  2. Angle of attack: oscillating above 23 units of attack
  3. Airspeed: oscillating between 110-140 knots
  4. Turn needle: pegged
  5. All four conditions met: apply spin recovery procedures

I flew over 30 years ago and I still remember these procedures. You might enjoy how I came to appreciate the seriousness of spin recovery. I had a decorated Skipper who had flown all through Vietnam in the A4 as an attack pilot. He stood up one day in the ready room and told us young'uns, "I don't care what you do out there, just make sure you brief it before you do it. Too many of us die because we impulsively decide to do something without thinking it through completely. Know your emergency procedures."

One night I was out at 25,000 feet tooling around after completing my mission, waiting to recover at the ship. A bit bored I had the thought, "I do loops in the simulator where it is blacker then this back home all the time. I have plenty of altitude to get the airspeed I need ... Why not?" And down I went. Unloading the aircraft to negative 1 or 2 G's I picked up airspeed well above what I needed and started pulling back up into the loop. It was dark out, no moon, with a solid cloud layer at 5,000 feet. I remember having an uncomfortable, anxious feeling at some point. Something wasn't right. I started paying attention. It was quiet. There wasn't the usual engine and wind noise! I came into the cockpit and the first thing that caught my eye was the full white of my rather large attitude indicator located in the middle of the instrument cluster. I had relaxed back pressure on the stick at some point. Oh my God. Not what you wanted to see in an A7: nose pointed straight up. Quickly glanced at my airspeed indicator to the left and watched it drop like a rock to the peg at 0 knots. Then the aircraft dropped backwards pushing the tail, and then entering a roll. I was along for the ride though. I wasn't thinking. I wasn't present. Spin recovery didn't enter my thoughts. Never checked my altitude. The aircraft dropped like a leaf for a bit and then settled in a descending roll. I put in opposite aileron and came out of it. Whew! Of course my gyros were toast and the inertial navigation system useless. I ended up coming through the solid overcast and doing my instrument approach to the ship on pressure instruments. I always followed my Skippers advice after that.

Eventually we came ashore and I found myself doing regular emergency procedure training in our simulators. Towards the end of one of these sessions I decided to practice spin recovery. I knew we couldn't get the simulator into a spin, but I thought it might be useful nonetheless. So every time I got to the simulator I made sure I practiced.

The next time I found myself at sea I had finished my flight, and was getting together with a section to practice air combat maneuvering: 1-v-2. We had agreed to meet at a point over the ocean, at a given time, with an altitude separation between flights. I had everything below 15,000 with 5,000 as the hard deck. they had 16,000 an above. You could get there early, or late depending on how you wanted to try to set up the fight. Eventually we set up radio comms. The rule was that we had to talk to one another until one of the flights had gained sight and could then maintain separation.

As I came in to the fight I decided to make a gamble. I unloaded the aircraft with 2 negative G's and descended quick to 5,000 feet. They wouldn't be looking for me that low and so I would be outside their scan for bogies. The top of my aircraft was painted this dull off gray and it blended in with the haze and blue-gray of the ocean underneath. The sky above was clear blue. The tactic payed off and I saw the flight at around 18,000 feet. They knew they were in trouble when I stopped answering their radio calls. I pulled up into an Immellman, but had bled off a lot of airspeed from the dive as I was level at 5,000 feet in the denser atmosphere. As I got to 18,000 feet I was directly behind the two airplanes and I saw my airspeed hit the peg. I quickly called 2 Aim-9 missile shots to win the fight. Then on my back at zero airspeed the automatic flight control kicked the rudder inadvertently, and the A7 entered a spin. How do I know? Well, the AOA was above 23, the airspeed was between 110-140, and the turn indicator was pegged. It was second nature and I was in full control of the situation. As I was assessing the situation I got a call from the other flight lead asking, "Hey where are you?" I replied calmly, "I am a bit busy hold on ..." After recovering from the spin we headed home.

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    $\begingroup$ Great story! Thanks for sharing it! $\endgroup$ – Carlo Felicione Jan 10 '17 at 0:05
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Entirely possible, although it is the turn coordinator not the artificial horizon that is primary -- to determine the direction of the spin. Nose-down elevator, rudder opposite the spin, the when spinning stops recover from the dive using airspeed & altimeter for pitch control & the turn coordinator for roll. Those instruments don't tumble.

I'm told that in the 1950s, spin recovery in simulated IMC was a requirement for some ratings (commercial, instrument, and/or ATP - not sure which). Not so much now, obviously, but with a suitable airplane and appropriate instruments, it is entirely possible.

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When I used to teach my IFR students, they usually spent only the first couple of hours with all of their instruments. I put them in all sorts of unusual attitudes and let them recover under the hood, and with "failed" instruments. And I sometimes included spins with the students I thought could handle it. That was what my instructor did to me, and I guess I carried on the tradition. It sucked. And I know my students had horrible thoughts of me at the time. But it made us better pilots. Especially in IMC. It taught me not to rely on the things that were more likely to fail and to quickly be able to interpret what my instruments were telling me. I went for a month in training thinking the Attitude Indicator and Directional Gyro looked like a suction-cupped soap holder. I don't think it's hard to tell you're in a spin; you just have to know what your plane is saying to you.

To your question: Is it possible to recover? Absolutely. Is it likely though? It depends. If you have a lot of altitude and you're in an aircraft that has decent spin characteristics, probably (especially since you mentioned prior spin training). But if you were at a couple thousand feet in a Piper Tomahawk, probably not. Would I recommend trying it? A big resounding NO!!!

And to your other question about AHRS: In a spin, the Attitude Indicator, no matter how accurate it might be, was the last thing I looked at in recovery. Unless it can demonstrate 100% reliability in all flight attitudes, it's safest to just assume it's lying to you.

Side Note: I recently did a balance function test with a physical therapist for an inner ear vertigo issue. She told me that pilots were some of the hardest people to test, specifically because we teach ourselves to ignore what our ears tell us. :-)

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    $\begingroup$ I'd imagine you're like that really hard nosed high school coach - everyone hates you during practice, but, years later, they look back and realize you were their favorite. $\endgroup$ – FreeMan Apr 29 '16 at 20:29
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    $\begingroup$ :-) Most of my former students went on to airline careers. I hope they remember the lessons I taught them, and I hope they feel like I do about my hard teachers. $\endgroup$ – Shawn May 2 '16 at 21:38
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Yes it is possible, but it takes more than training; it takes practice

Point of reference/experience: Flight Instructor and Standardization Instructor, three years, US Navy.

  • Caveat 1: I'd suggest not getting into a spin in IMC in the first place, by flying smoothly and making "do not stall" an imperative that your life depends on. (See the AF 447 accident, an A330, which was not even a spin -- "merely" a stall -- that killed them all. The investigation showed that spin in IMC and stall in IMC training, was not part of the A330 training syllabus. Approach to stall/stall prevention was).

    If you want to be prepared for the unusual case, you still have to both train for it AND *stay proficient. Some skills atrophy with disuse but can be relied upon when exercised -- just like a muscle. Instrument scans and partial panel instrument scans are in that skill category -- big time.

  • Caveat 2: Make sure you are already proficient at spin recovery in VMC/VFR in your aircraft

    In the following discussion, the term Attitude Gyro means your aircraft's primary attitude reference system, which is your primary scan item when flying in instrument conditions.

Two cases:

  1. With Attitude Gyros that don't tumble (Can handle the 3-d environment).

  2. With Attitude Gyros that tumble (can't handle the 3-D environment)

Case 1

You are able to use the attitude gyro and your other instruments, so you can adapt whatever full panel instrument scan appropriate for that maneuver (spin recovery) just as you could do aerobatics like a barrel roll or half Cuban eight on the gauges. (The FTI for the T-45, barrel roll, is on page 3-24 of this link). Whatever the case, follow the procedure for your aircraft and keep that instrument scan going. Do everything in your power to ignore the weird feelings that the 3-d rotation is telling your body, and trust your instruments.

WARNING: Use the procedure specific to your aircraft, the procedure for spin recovery. In general, this means that you:

  1. confirm spin (which is a stalled condition with rotation);

  2. confirm direction of spin;

  3. apply anti-spin control inputs specific to your aircraft;

  4. stop spin (and note that airspeed is increasing);
    If you don't have an Angle of Attack indicator, your airspeed and attitude are your cues

  5. recover from ensuing unusual (usually nose down) attitude.

Case 2

In case 2, you are dealing with a serious emergency procedure, since you have to rely on a partial panel scan as your attitude gyro will tumble. (That means that it will lie to you). This is from personal experience. I had to do IMC spin recoveries to earn my special instrument card -- I also ran a number of Instructors through this drill for their training.

You have to do everything for Case 1 but you have to do it While Ignoring That Non-Functioning Attitude Gyro, and forcing yourself to smoothly stop the (disorienting) rotation by only scanning your other instruments: Airspeed/Turn Needle-Ball/Altitude/VSI ... all of which are cross check instruments in a normal instrument scan based on the attitude gyro. This can be difficult to do since your trained reflex, your habit, is to refer to your Attitude Gyro in IMC. It takes an act of will to ignore it and only scan the other instruments.

The First Time You Try it you may not get it right

During my first ever "spin under the bag" the Standardization Instructor (SI) had to take the controls since I had un-stalled/unspun the aircraft but I was doing a 'rolling pull out' which our NATOPS manual prohibited. My next one was acceptable, if not pretty. I had been teaching instrument flying, also teaching partial panel techniques, and flying both for about a year. I was both current and proficient in both and flying 30-40 training sorties per month, about a third of which were instrument sorties. Even if you are a decent instrument pilot, it can be a challenge.

When I was the SI, I noticed that most of the pilots took one or two tries to get it right and then would have the technique down.

Why proficiency matters

I caught mononucleosis and was grounded for two months. My back-in-the-saddle flights (I got 3) was to get me back up to speed on all quals, and that included "spin under the bag" since I was a Stan Instructor. My first attempt was barely satisfactory (my completed recovery was ~ 400 feet above the hard altitude, and my SI debriefed me that he nearly took the controls). I'd been doing and teaching this for six months, I knew the procedure, but being a little rusty was all it took to nearly goon it up. I can still recall how hard I worked on that recovery to keep my scan going and be smooth. It was humbling.

Bottom Line

Know your aircraft, know your spin recovery, practice your instrument scan, and (if you have a gyro that tumbles in a spin) practice your partial panel scan.

It can be done, but you have to keep those (procedures) muscles toned. Spin in IMC (and for that matter, stall in IMC) is a case where An Ounce of Prevention is far better than a Ton of Cure: don't get into a spin (or even a stall) in IMC. Make that a priority like your life depends on it. (It does).

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    $\begingroup$ A pleasure to serve. Fly safe! :-) $\endgroup$ – KorvinStarmast Jan 9 '17 at 18:40
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It's certainly possible, but also highly unlikely. It's possible because - ignoring thunderstorms, icing or other extreme conditions - being inside a cloud doesn't change how the aircraft handles or how to recover from a spin.

The real challenge would be to recognize that you're in a spin and react quickly. With no visual reference, the only way to know you're spinning is to deduce it from the instruments, and it could be very difficult for you to interpret them correctly and in time to prevent a crash. Even more difficult if some have toppled or become unreliable.

It's true that "unusual attitude" recovery is part of instrument training in the US (and probably most other places), but the training exercises are usually based on steep, turning climbs and descents or near stalls. I couldn't find any solid information on spin training under the hood, but personally I think it's highly unlikely that most pilots would survive, unless perhaps they have an airframe parachute and deploy it promptly. Or they break out of cloud with enough altitude - and presence of mind - to recover safely. I've never heard of an instructor spinning an aircraft with a student under the hood, although I suppose there's no specific reason not to.

Finally, it's often mentioned that in the early days of aviation, spinning was used as a way to descend through a narrow hole in clouds or even directly through the clouds. It was a 'convenient' way to lose altitude quickly while staying in more or less the same place. On the other hand, I've never read a first-person account of that (maybe someone else has?) and without knowing for sure where the cloud bases are it would be extremely dangerous. But every description I've seen also says that pilots spun through the clouds before recovering in VMC, which is a different situation anyway.

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