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The Graveyard spiral is an extremely dangerous situation and is the leading cause of a controlled flight into terrain accident. It is caused by the erroneous feedback from the vestibular system that the aircraft is in level flight when in fact it is descending and banking. However, my question is, is it possible to recover from a graveyard spiral1 in zero visibility conditions2? Even more importantly, in zero visibility conditions, will a pilots be able to even notice that the aircraft is in a graveyard spiral? If so, how do pilots notice the situation in zero visibility conditions, and what course of action should/will be taken to recover? I'll appreciate any insights on this, preferably from an experience pilot or flight instructor. Thanks in advance!

Notes:

1: It must have an extremely high fatality rate, it's called "graveyard" after all. The other names given by Wikipedia for this phenomenon seems even worse, "death spiral", "deadly spiral", "suicide spiral", "vicious spiral" all seem to convey the same meaning, eg. it's usually not survivable. Or are the names exaggerating things?

2: I know a common method to recover is to consciously override the vestibular feedbacks and rely on visual cues instead. However, in zero visibility conditions, there's no outside visual cues, no horizon or the like. So it seems like it's going to be nearly impossible to recover if this is the case. Making life-or-death decisions relying only on electronic instruments that may be erroneous when your whole body is telling you otherwise is nearly impossible, I think. Or am I wrong? Do pilots tend to believe in their instruments more than their own body's senses?

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    $\begingroup$ If you're in zero visibility and you aren't looking at your artificial horizon, what are you even doing? $\endgroup$
    – Darth Pseudonym
    Commented Sep 4 at 18:59
  • $\begingroup$ Any comment from downvoters? Please inform me of any possible improvements. I hope to make this post useful to future readers, so if there's anything I can improve, please tell me. I'm also welcome to any edits. I'll appreciate any help. Thanks in advance! $\endgroup$
    – Aircraft Enthusiast 007
    Commented Sep 4 at 23:02
  • $\begingroup$ I don't specifically know about the downvotes, but I can say that some of your phrasing suggests that you aren't familiar with flight operations at all. That's not a sin in my view -- there's nothing wrong with ignorance, especially when the context is that you're actively trying to change that, and it's not like basic questions detract from the more complex/nuanced questions -- but this particular section of SE seems to be pretty hard on people who aren't deeply knowledgeable about aviation to start with. $\endgroup$
    – Darth Pseudonym
    Commented Sep 5 at 16:05
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    $\begingroup$ Specifically, your footnote that "life-or-death decisions relying only on electronic instruments that may be erroneous" is quite the opposite of how pilots generally think. The instrument may fail, but if it fails it would (usually) be very obviously faulty, and airliners have redundant systems for anything critical. A mechanical system is much more trustworthy than your fallible wet meat that developed to operate in a generally two-dimensional environment at no more than a couple dozen miles per hour and is now being asked to comprehend a mid-air world moving at 10 to 20 times that speed. $\endgroup$
    – Darth Pseudonym
    Commented Sep 5 at 16:11

4 Answers 4

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Do pilots tend to believe in their instruments more than their own body's senses?

This is EXACTLY what you're taught to do in any instrument training, and the reason that training is mandatory to fly in instrument meteorological conditions. It is unnatural and does not come easily.

So while stall recovery is no doubt harder in IMC, and I would not like to try it, the answer to your question is yes, it is survivable as long as you trust your instruments and recover appropriately.

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    $\begingroup$ Doing stall and spin recoveries under the hood is an invaluable part of IFR training. Not many places even offer it, but you can always ask. And if they say no, it is worth doing some hunting to find a place that will. Yes, of course, the better route is to not get into such a situation in the first place. But people make mistakes, and knowing how to recover from such a fantastically dangerous mistake can mean the difference between finishing your trip with soiled underwear and finishing it in a hearse. $\endgroup$
    – Pete Danes
    Commented Sep 4 at 14:44
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    $\begingroup$ Adding on to this: pilots are taught this not just because of a lack of visual references in many IMC scenarios, but because of the somatogravic illusion; the inner ear isn't good at differentiating acceleration from pitch, yaw, and roll moments along the same axes, which can lead to confusion. Working, calibrated instruments can effectively discriminate between all of that. $\endgroup$
    – Jules
    Commented Sep 4 at 16:10
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    $\begingroup$ Voting down as slightly off topic. The question never mentioned stalls or stall recovery. $\endgroup$
    – Robert Chapin
    Commented Sep 4 at 17:34
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    $\begingroup$ @Jamiec I think the image on the linked wikipedia page clearly distinguishes the intended difference in meaning between "spiral" and "spin". The spiral is just steady controlled banking descent into terrain, not noticed because of the vestibular system being tricked (and not paying enough attention to/believing the instruments). $\endgroup$
    – llama
    Commented Sep 4 at 17:59
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    $\begingroup$ @Jamiec Spirals and spins are very different flight conditions and require very different recovery techniques. In a spiral, neither wing is stalled and recovery is as simple as leveling the wings with the ailerons and then bringing the nose up without overstressing the airframe. Trying to level the wings with the ailerons in a spin will just aggravate the spin. $\endgroup$
    – Chris
    Commented Sep 4 at 18:17
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Pilots do not 'tend' to believe our instruments - we are trained to believe them. We have to, because our senses are not reliable in such situations. Yes, if you follow your gauges and ignore what the seat of your pants is telling you, such a situation is completely and easily recoverable, provided you have enough altitude. But following your gauges is also the best method for not getting into such a situation to begin with. That's what instrument flying training is all about, and even pilots who have no intention of ever flying in bad weather should get at least a little. It can easily save your life.

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    $\begingroup$ Yep. Though to be totally fair, there have been a number of airline accidents and incidents that happened (at least in part) because in a moment of stress, the pilot flying didn't believe their instruments and tried to trust their feelings instead. Instruments can fail, but they fail a lot less often than the human body. $\endgroup$
    – Darth Pseudonym
    Commented Sep 4 at 19:00
  • $\begingroup$ I think this happens far more often in general aviation than the airlines, although I do not have actual statistics at hand. But airline pilots are pros, and regularly undergo training. GA pilots often get into trouble because they do not have such training, or what they have is seriously out of date. This is an extremely easy situation to avoid, IF you're clear and current on procedures. $\endgroup$
    – Pete Danes
    Commented yesterday
  • $\begingroup$ Oh, no doubt. It's not common, but it has happened more than a couple of times over the last 40 years, and it's usually on airlines that already have poor oversight, poor training budgets, and/or bad pilot culture. Removing the support structures that would help prevent foolish mistakes. $\endgroup$
    – Darth Pseudonym
    Commented 2 hours ago
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Making life-or-death decisions relying only on electronic instruments that may be erroneous when your whole body is telling you otherwise is nearly impossible, I think. Or am I wrong? Do pilots tend to believe in their instruments more than their own body's senses?

This is a required part of even private pilot training. The student's view outside is covered, and then the student is made to lower their head or close their eyes while the instructor does their best to confuse the student's vestibular system and then leaves the airplane in an unusual flight attitude. The student then needs to recover to normal flight using only their instruments. This is emphasized even more in instrument training.

Instruments can be wrong, but they are much, much more reliable than the pilot's vestibular system, which will fail very quickly once visual references are gone. Still, the fact that they can be wrong is worth addressing. The instruments required for IFR flight are redundant by design. In instrument training, pilots are trained to cross-check their instruments to identify when one is giving erroneous results and continue flying safely when one or more instruments have failed.

This training is not always enough. While "partial panel" training is a large part of instrument training, real life partial panel situations with minimum equipment in actual IMC often end badly. Airplanes used in the airlines have additional redundancy in their instruments to keep any single point of failure from putting the pilots in too difficult of a situation. All of them have at least two attitude indicators, and most of them have three.

In one sense, the actual recovery from a graveyard spiral is not especially difficult. Simply level the wings with the ailerons and push or pull as needed. The airplane will naturally pull up as it seeks its trimmed angle of attack. At higher airspeeds it will do so too aggressively and risks overstressing the airframe or stalling unless you push to unload the wings.

In another sense, it's very difficult. If you got into a developed graveyard spiral, it's probably because you were disoriented and not trusting your instruments. Realizing you're disoriented, reorienting yourself off your instruments, and recovering in what little time you have is not an easy task.

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  • $\begingroup$ Briefly, yes - you are wrong. It takes training, but it is not 'nearly impossible' by any stretch of the imagination. It is quite simple, truthfully, but it does take some training and practice. And once again, a proficient pilot will simply not get into such a situation, because he knows how to prevent it. It is not something that 'just happens' - it is the culmination of a series of mistakes, and takes a while to develop. A competent pilot will never let that happen. $\endgroup$
    – Pete Danes
    Commented yesterday
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Yes, it is possible to recover. I wanted to add more context as well.

I once helped a primary flight student recover from a graveyard spiral initiated during a steep turn maneuver in visual conditions. There's more going on here than just instruments and vestibular feedback.

A graveyard spiral is also distinctly characterized by mechanical feedback. When the airplane is in a descending turn, one of the most intuitive reactions is to try to raise the nose of the airplane by pulling on the control yoke. However, beyond a reasonable angle of bank, attempting to raise the nose of the airplane makes the spiral tighter and worse in all respects. This part was mentioned in the Wikipedia article but it was not explained very clearly.

In other words, the "stick and rudder" skill level of the pilot contributes directly to the entry and development toward CFIT or to recovery from this maneuver.

Yes, pilots are trained to recognize the effects of "load factor" in a variety of aircraft attitudes, to include the phenomenon of a spiral descent.

How it's done, in zero visibility, is primarily by recognizing an abnormal angle of bank (attitude) and rate of turn (heading), which should be understood as a need for decreased bank by rolling in the opposite direction of the turn. This is a component of the exercise known as "unusual attitude recovery."

While electronic instruments can have a variety of faults and failure modes, they are generally extremely reliable. Pilots learn that a single point of failure should affect only one instrument or a small subset of related instruments.

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