flymatt2bermud
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Spacial Disorientation (research)

Sat Feb 10, 2007 6:03 am

Does anyone have any sources on the topic Spacial Disorientation. I am doing some research on the subject and I want to like to see were I can find the latest materials. Also, if anyone has any stories to share I would love to hear them. I know there have been previous threads pertaining to this but it's been a while.

Thanks all,
M
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
 
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Starlionblue
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 6:11 am

I only have anectodal stories from a couple of Italian AF fighter pilots I spoke to. The pilot instructor of the pair said that the body can play pretty nasty tricks on your brain. You're flying straight and level at night over water and your brain slowly becomes convinced you are rolling ever so slowly to the left. So you automatically compensate (erroneously) and are now actually rolling to the right. But your brain is not convinced, and slowly but surely senses that you are still rolling to the left.

Basically you need to trust your instruments. Or the Force.

BTW it is spelled "spatial". Trust English to be illogical.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
sevenair
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 7:13 am

http://en.wikipedia.org/wiki/Spatial_disorientation has some good information on this and some additional links.
 
oly720man
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 9:52 am

NASA have a few reports

http://ntrs.nasa.gov/search.jsp and enter the search terms

but unfortunately they're not online so you'll have to order them or get them through a library.


http://www.aopa.org/whatsnew/newsitems/2002/02-2-008.html
there's a link to a pdf at the end.


http://www.ecn.purdue.edu/HIRL/projects/nasa2000/life_sci.html

http://www.medind.nic.in/iab/t02/i2/iabt02i2p59.pdf

[Edited 2007-02-10 01:59:21]
wheat and dairy can screw up your brain
 
N231YE
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 10:17 am

Quoting Starlionblue (Reply 1):

There are actually quite a few of these effects, like the "graveyard spin"
 
speedracer1407
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 4:44 pm

Quoting Starlionblue (Reply 1):
You're flying straight and level at night over water and your brain slowly becomes convinced you are rolling ever so slowly to the left. So you automatically compensate (erroneously) and are now actually rolling to the right. But your brain is not convinced, and slowly but surely senses that you are still rolling to the left.

Spatial disorientation is no doubt a serious danger to any pilot, but as a non-pilot, I have a hard time placing myself in a situation in which my instruments failed to give me clear enough information to confirm the plane's attitude--which leads me to some questions:

In zero visibility conditions, wouldn't a pilot be on high-alert for the symptoms of SD such as a slow role or pitch in one direction that seems to require constant and unexpected attention? Shouldn't a quick scan of the HSI and VSI confirm or deny his or her plane's attitude in an instant?

Is SD usually the result of pilots consciously choosing to react to seat-of-the-pants sensations INSTEAD of their instruments--even after a quick scan reveals straight and level flight?

Is there enough precedent to give experienced pilots a reason to distrust instruments when they clearly display the indented flightpath and attitude? I recall a few incidents/disasters in which a blocked pitot tube or other failure rendered a critical instrument faulty, but I don't recall those incidents leading to what I perceive as a "traditional" moment of SD.

I'm not denying the validity of SD as a serious phenomena, nor am I implying that pilots who are victims of SD are incompetent. But like the original poster, I'm wondering if there are other factors that can lead to SD other than simple (for an IFR pilot) lack of exterior visibility.
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redcordes
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 8:58 pm

I've never experienced these, but a group of illusions that result from the body being unable to distinguish between pitching up and accelerating (both conditions force the pilot against the back of the seat) and pitching down and decelerating (both force the pilot forward in the seat). I think that without adequate visual clues, the brain's first impulse is to assume a change in attitude. Don't hear much about these, so I thought you might be interested. Here's some info:

Vestibular/Somatogravic Illusions

Somatogravic illusions are caused by linear accelerations. These illusions involving the utricle and the saccule of the vestibular system are most likely under conditions with unreliable or unavailable external visual references.

Inversion illusion

The inversion illusion involves a steep ascent (forward linear acceleration) in a high-performance aircraft, followed by a sudden return to level flight. When the pilot levels off, the aircraft speed is relatively higher. This combination of accelerations produces an illusion that the aircraft is in inverted flight. The pilots response to this illusion is to lower the nose of the aircraft.

Head up and down illusions

The head-up illusion involves a sudden forward linear acceleration during level flight where the pilot perceives the illusion that the nose of the aircraft is pitching up. The pilot's response to this illusion would be to push the yoke or the stick forward to pitch the nose of the aircraft down. A night take-off from a well-lit airport into a totally dark sky (black hole) or a catapult take-off from an aircraft carrier can also lead to this illusion, and could result in a crash.

Head-Down Illusion

The head-down illusion involves a sudden linear deceleration (air braking, lowering flaps, decreasing engine power) during level flight where the pilot perceives the illusion that the nose of the aircraft is pitching down. The pilot's response to this illusion would be to pitch the nose of the aircraft up. If this illusion occurs during a low-speed final approach, the pilot could stall the aircraft.
"The only source of knowledge is experience." A. Einstein "Science w/o religion is lame. Religion w/o science is blind."
 
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Starlionblue
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RE: Spacial Disorientation (research)

Sat Feb 10, 2007 11:00 pm

Quoting Speedracer1407 (Reply 5):
In zero visibility conditions, wouldn't a pilot be on high-alert for the symptoms of SD such as a slow role or pitch in one direction that seems to require constant and unexpected attention? Shouldn't a quick scan of the HSI and VSI confirm or deny his or her plane's attitude in an instant?

Of course. The point these guys were driving at was that one should suppress instinctive reactions and look at the instruments in these conditions.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
N231YE
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RE: Spacial Disorientation (research)

Sun Feb 11, 2007 12:37 am

Quoting Speedracer1407 (Reply 5):
Shouldn't a quick scan of the HSI and VSI confirm or deny his or her plane's attitude in an instant?

Yes, but it is a good idea to look at all 6 instruments.

Quoting Speedracer1407 (Reply 5):
Is SD usually the result of pilots consciously choosing to react to seat-of-the-pants sensations INSTEAD of their instruments--even after a quick scan reveals straight and level flight?

Yes. Instrument pilots are taught to trust their instruments...not their instinct. A good instrument pilot is constantly scanning (besides doing other things).

Quoting Speedracer1407 (Reply 5):
Is there enough precedent to give experienced pilots a reason to distrust instruments when they clearly display the indented flightpath and attitude? I recall a few incidents/disasters in which a blocked pitot tube or other failure rendered a critical instrument faulty, but I don't recall those incidents leading to what I perceive as a "traditional" moment of SD.

Again, yes. For example, even if the attitude indicator fails, you can tell you are making a climbing turn if the airspeed is low, altimeter is increasing, turn coordinator is not "wings level," directional gyro is turning, and VSI is showing a positive rate of climb. I am not an instrument pilot yet, but that was one thing that I was taught in PPL training "under the hood" or in real IMC, was to identify a maneuver if one or a few instruments failed in flight.

Quoting Speedracer1407 (Reply 5):
I'm not denying the validity of SD as a serious phenomena, nor am I implying that pilots who are victims of SD are incompetent. But like the original poster, I'm wondering if there are other factors that can lead to SD other than simple (for an IFR pilot) lack of exterior visibility.

SD can also be caused by medical phenomenon to. For example, people with ear infections can become dizzy and nauseated, even though they may be resting in a bed. Why? Often, the ear infection affects the body's secondary sensory organ(s), the Vestibular System, which is located in the inner ear. Drugs will also aggravate spatial distention, most notoriously is alcohol.

However, the main reason SD occurs is simply due to the lack of your primary sensory input, your vision. As I was taught, simply taking away vision (such as in IFR) is what causes disorientation.

>>Do this: take a paper towel or toilet paper roll tube and hold it up to (against) your eye. Close the other eye, and try balancing on one foot. Suddenly, it becomes difficult. Why? The tube restricts your peripheral vision, and suddenly and so quickly it becomes extremely difficult to stand. Your body, by instinct, will use your inner ear and nervous system to balance. And that is standing on the earth, a surface which is still. Now Try doing that in an airplane, with 3 axis of movement. It seems difficult to understand to the non-flyer, but simple "experiments" such as these will make you realize why SD occurs.

I tried to explain this as best as I can (from what I remember), so I hope this helps.

-N231YE
 
CosmicCruiser
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RE: Spacial Disorientation (research)

Sun Feb 11, 2007 1:46 am

The most serious case I ever had was many years ago flying a Beech 18 . It was night and no A/P and I was IFR with just occasional breaks in the clouds. As I flew along I caught sight of just a couple of stars above me thru a small break. Everything was still ok until I looked down thru a small break and saw a couple of single lights on the ground(I was over unpopulated terrain). Instantly I felt that the plane was banked steep to the left and that those 2 lights on the ground were stars as well. All I can say is that my concentration was 110% for the next 20 min or so untill I got a good look at the ground and more lights. I won't forget that moment. I can't say I've really had it in the last several years though. I don't know why maybe I just don't "feel" it anymore cause looking at the inst. are too normal.

Quoting Speedracer1407 (Reply 5):
I have a hard time placing myself in a situation in which my instruments failed to give me clear enough information to confirm the plane's attitude--which leads me to some questions:

That's because you aren't really moving and had the inner ear thing going on if you're doing FS. Redcordes gave a good description that I won't repeat.

Quoting Speedracer1407 (Reply 5):
wouldn't a pilot be on high-alert for the symptoms of SD such as a slow role or pitch in one direction that seems to require constant and unexpected attention? Shouldn't a quick scan of the HSI and VSI confirm or deny his or her plane's attitude in an instant?

If you are a proficient instr. pilot, yes; if not, no. That's what always gets the non-instr. rated pilot in IFR conditions. From Buddy Holley's pilot to JFK jr.
 
flymatt2bermud
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RE: Spacial Disorientation (research)

Mon Feb 12, 2007 12:14 am

Quoting Speedracer1407 (Reply 5):
Spatial disorientation is no doubt a serious danger to any pilot, but as a non-pilot, I have a hard time placing myself in a situation in which my instruments failed to give me clear enough information to confirm the plane's attitude--which leads me to some questions



Quoting Speedracer1407 (Reply 5):
I'm not denying the validity of SD as a serious phenomena, nor am I implying that pilots who are victims of SD are incompetent. But like the original poster, I'm wondering if there are other factors that can lead to SD other than simple (for an IFR pilot) lack of exterior visibility.



Quoting Redcordes (Reply 6):
Vestibular/Somatogravic Illusions

Somatogravic illusions are caused by linear accelerations. These illusions involving the utricle and the saccule of the vestibular system are most likely under conditions with unreliable or unavailable external visual references.

Speedracer, Vestibular/Somatogravic disorientation is more common during low visibility (e,g, night, IFR, no horizon reference) flying and it can happen to anyone. The human vestibular system functions by sending linear movement information to the brain. The problem is this system is susceptible to error. The vestibular system utilizes three semicircular canals located inside each ear that work like gyroscopes measuring movement lateral to their position (they are organized in three planes perpendicular to the others, this enables you to sense acceleration basically in forward/aft, tilting to left/right and up/down). The canals structures are filled with a gelatin type of substance, tiny hair follicles called cilia line the outer structure. As you move, the liquid in the canal is delayed by the natural law of physics, this causes the cilia to move in the opposite direction thus providing instantaneous information to your brain to interpret the movement. When the movement stops the cilia roll the other direction sensing that you have changed the speed of movement or stopped.

The problem can occur when you begin a perfect standard rate turn, the cilia sense the turn initially and everything is perfect right? Yes, well so far that is, but you continue that perfect turn for 30 seconds of more, the gelatin fluid in your ears eventually stabilize no longer sensing a turn. Then when you come out of the turn the cilia sense this and send a message to your brain that you are now rolling the other direction, still not a problem yet, but then when you level your wings, the cilia sense that you have started banking in the opposite direction. If for whatever reason you are not confident of your horizontal reference, you going to experience SD. Unfortunately, you cannot resume straight and level based upon your vestibular information (it is inaccurate). The only thing you can do to reset your vestibular input is fly straight and level for about 2 minutes to allow the gelatin to stabilize. In the meantime, it is hard to ignore your senses and trust your instruments. When you do not have the training and experience to fly solely by reference to your instruments it can spell disaster. Such as the graveyard spiral.

[Edited 2007-02-11 16:21:04]
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci

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