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-   -   Advanced avionics artificial horizon question (https://www.airlinepilotforums.com/hangar-talk/117345-advanced-avionics-artificial-horizon-question.html)

Hawker445 10-12-2018 06:12 PM

Advanced avionics artificial horizon question
 
Ok so pardon my vocabulary on asking the question, so there might be some confusion.

OK

So in conventional/analog attitude/artificial horizons the bank angle pointer moves with the airplane and the angle ticks are level with the horizon. But in the Proline/Honeywell itís all swapped.

When I first flew a jet and saw the pointer stay level with the horizon it just made my brain go bizerk.

Whatís the reasoning behind this?

rickair7777 10-13-2018 09:15 AM

IMO the certification agencies should dictate some very fundamental standards for attitude depiction. Otherwise every manufacturer comes up with their own scheme, which they assume to be "better" for whatever reason. I know as fact that in some cases "better" simply means that it doesn't infringe on an existing intellectual property. The problem arises of course when pilots fly an airplane with a different scheme than they are accustomed to... it took me far too long to comfortable transition from one such scheme to another once. It was fine if I thought about it but as soon as I got busy I reverted to "second nature" which of course was the last jet.

You could even have several available schemes, and each pilot chooses the one he wants to use with the flip of a switch. But the same basic options should be available on all glass planes. With glass, it would be software, no new hardware required.

Same for basic GPS/RNAV/FMS menus, that could be standardized (with all the gee-whiz crap hidden away in an optional menu, just in case you wanted to go there).

Twin Wasp 10-13-2018 10:39 AM

It's so we can call it a "sky pointer."

vessbot 10-13-2018 03:35 PM

I like the old way much better. And I've got a lot more instrument time looking at a new type (sky pointer) panel, so you can't accuse me of favoring familiarity. I think the sky pointer is downright stupid, for some objective reasons.

First, it violates a basic general scheme that tick marks are fixed to some outside-world fixed reference scale, with a single pointer representing the value of interest (or the thing we're controlling) and we try to control it to go the tick mark we want. Look at anything else: altitdue, heading, vertical speed, air speed. With the sky pointer that's backwards: we're taking the tick marks around with us, and the "outside world" fixed reference is the single marker. And that by itself wouldn't be so bad, if it wasn't in combination with the second general scheme that is violated:

At the center of the whole attitude indicator (old-style mechanical and sky pointer EFIS alike) is the airplane symbol, the thing that's locked to us, the pilot, and airplane. All around it (again, in both systems) is the "outside world:" the movable ground/horizon/sky that we're operating within. We fly our little airplane symbol around the "outside world" on the screen, a duplication of the real airplane and real outside world. OK, good so far. Now bring the sky pointer into it... at the top we have the sky pointer (representing the outside world) INSIDE of (and closer to the airplane symbol than) the bank angle tick marks that are fixed to the airplane. It's an inversion, or outside-in. It would be more intuitive and easier if the the airplane-fixed element was on the inside, close to the airplane symbol; and the outside-fixed element (the sky pointer) on the outside

It's a crap system. Maybe it was designed by human factors eggheads that have done the hard work to find it's really a better system despite my criticisms, but I think it's likelier that it was done for a dumber reason. (It wouldn't be the first ergonomic/human factors atrocity to make its way into a cockpit.) What I keep hearing is that it shows you a sky pointer that you know you're supposed to roll toward if you get disoriented... but guess what, the old style attitude indicators have one too, just on the outside where it belongs!

JamesNoBrakes 10-13-2018 03:39 PM

It's pretty terrible IMO. "Standard" is much more intuitive. I'd hedge that human factors studies would prove this if studies were run. I know of (before my current career in regulation) avionics manufacturers that ran studies on certain displays where no performance difference was found between certain "gee whiz" displays and more basic stuff and they had the results sealed and made the participants/scientists sign a non-disclosure agreement about the results. All about money.

Hawker445 10-13-2018 04:08 PM

Quote:

Originally Posted by vessbot (Post 2690860)
I like the old way much better. And I've got a lot more instrument time looking at a new type (sky pointer) panel, so you can't accuse me of favoring familiarity. I think the sky pointer is downright stupid, for some objective reasons.

First, it violates a basic general scheme that tick marks are fixed to some outside-world fixed reference scale, with a single pointer representing the value of interest (or the thing we're controlling) and we try to control it to go the tick mark we want. Look at anything else: altitdue, heading, vertical speed, air speed. With the sky pointer that's backwards: we're taking the tick marks around with us, and the "outside world" fixed reference is the single marker. And that by itself wouldn't be so bad, if it wasn't in combination with the second general scheme that is violated:

At the center of the whole attitude indicator (old-style mechanical and sky pointer EFIS alike) is the airplane symbol, the thing that's locked to us, the pilot, and airplane. All around it (again, in both systems) is the "outside world:" the movable ground/horizon/sky that we're operating within. We fly our little airplane symbol around the "outside world" on the screen, a duplication of the real airplane and real outside world. OK, good so far. Now bring the sky pointer into it... at the top we have the sky pointer (representing the outside world) INSIDE of (and closer to the airplane symbol than) the bank angle tick marks that are fixed to the airplane. It's an inversion, or outside-in. It would be more intuitive and easier if the the airplane-fixed element was on the inside, close to the airplane symbol; and the outside-fixed element (the sky pointer) on the outside

It's a crap system. Maybe it was designed by human factors eggheads that have done the hard work to find it's really a better system despite my criticisms, but I think it's likelier that it was done for a dumber reason. (It wouldn't be the first ergonomic/human factors atrocity to make its way into a cockpit.) What I keep hearing is that it shows you a sky pointer that you know you're supposed to roll toward if you get disoriented... but guess what, the old style attitude indicators have one too, just on the outside where it belongs!


Shesh. Didn’t think it was that unpopular, just thought there was some trick that I was missing. I would seriously need some time to adjust my proficiency skills if I were to ever to hand fly an approach in IMC. I feel Like it just screws my instrument confidence and gets me disoriented every time I go back and forth. I’ll probably find something on flight simulator and do some basic turns/unusual attitudes.

vessbot 10-13-2018 04:26 PM

Quote:

Originally Posted by Hawker445 (Post 2690880)
Shesh. Didnít think it was that unpopular, just thought there was some trick that I was missing. I would seriously need some time to adjust my proficiency skills if I were to ever to hand fly an approach in IMC. I feel Like it just screws my instrument confidence and gets me disoriented every time I go back and forth. Iíll probably find something on flight simulator and do some basic turns/unusual attitudes.

Well, I wouldn't take my post as any measure of its general popularity. It's just my opinion, and this is probably the first time I've discussed it with anyone. As far as any "tricks," I'd start by trying to ignore everything at the top of the screen and just flying the airplane symbol and the horizon. After some of time of doing it that way, the motions of all the top of the screen stuff will start taking root in its familiarity (all the time you're ignoring it, you're still passively seeing it with your peripheral vision anyway).

vessbot 10-14-2018 02:38 PM

This thread got me curious as to whether I'm full of it, so I did a quick Google search and found this experiment (http://www.humanfactors.lth.se/filea...re/Horizon.pdf), which tested a group of pilots with both types of attitude indicators, and the sky pointer type yielded 5 times as many errors as the GA type. This is despite that the entire test group had more recent experience with the sky pointer type in real life.

Hawker445 10-15-2018 02:40 PM

Quote:

Originally Posted by vessbot (Post 2691287)
This thread got me curious as to whether I'm full of it, so I did a quick Google search and found this experiment (http://www.humanfactors.lth.se/filea...re/Horizon.pdf), which tested a group of pilots with both types of attitude indicators, and the sky pointer type yielded 5 times as many errors as the GA type. This is despite that the entire test group had more recent experience with the sky pointer type in real life.

I was about to post the exact same thing. Now this study was conducted a number of years ago so who knows how training has changed to adjust to it. But nonetheless I found the results that came out of it a tad alarming. Maybe i'm missing something ..But it makes me curious which is better for initial training and proficiency. Because...law of primacy dominates..

450knotOffice 12-02-2018 09:25 PM

Interesting discussion about nothing, imo. I grew up in the GA world with 2000 hours staring at a GA style ďbank indexĒ. Then I was hired by a commuter airline (thatís what they called them in the 80ís and 90ís). Interestingly enough, I noticed the difference between my old bank index and the new (to me) sky pointer during my first sim session. However, I adapted because it just wasnít that big of a deal.

Fast forward 27 years and 19,000 more hours, and itís all I know. When I hop in a GA airplane, I notice the bank index again, but just shrug and move on without second thought.

Who cares? Theyíre simply a variation on a theme - tomato, tomaahhhto.


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