Attitude Indicator vs Artificial Horizon

[Thair81]

I was wondering if there is any body who could answer a relatively simple question for me. I was having a stupid debate with another guy about attitude indicators and artificial horizons (I did say it was stupid). He was telling me that they are two different instruments with the AH being a much more complex instrument. I was under the impression that the AI and AH are the same thing just that the term "Artificial Horizon" is just an outdated term and "Attitude Indicator" is the modern name for what is the same instrument. Anyway, does anybody have any input. Are the AI and AH the same thing or different?

[bigsky]

Attitude indicator is usually related to ones pay stub.
An artifical horizon is installed in an aircraft.

GOOGLE has an answer for just about everything

http://en.wikipedia.org/wiki/Attitude_indicator

or

http://en.wikipedia.org/wiki/Artificial_horizon

..one in the same..

[CID]

The main difference lies in the system architecture. An artificial horizon (AH) is normally associated with an indicator with a self contained gyro. An attitude indicate (AI) is normally associated with a system that uses a remote attitude gyro and a "dumb" indicator.

The remote gyro can be anything from a simple "vertical gyro" to an INS platform.

One step from there is the flight director indicator which can use an integrated or remote gyro but provides flight control cues through a variety of methods including cross pointers and the chevron style symbol sometimes known as "chicken legs".

[ninjacrumb]

They're the same thing.

[oldtimer]

Largest difference is in the bank indicator at the top of the instrument. In an AH, the poiner points at the angle of bank and in an AI, it points at the sky, so the indications are the opposite. Or is it the other way round? I forget. Confuses the shit out of those who realized the difference but you get used to it. AI's are more expensive.

As an interesting sidenote, Russian Attitude Indicators are the opposite of Western ones. In a Western AI, the airplane symbol remains stationary and the "horizon" moves, as if you are looking out the window. On the Russian AI's, the horizon is stationary and the airplane symbol moves, as if you were looking at the airplane from behind. Has anyone experience one and if so, what did you think of it???

[Red Line]

Just like "Heading Indicator" versus "Directional Gyro", AI and AH are two different terms for exactly the same instrument.

[Cat Driver]

What you need to worry about is can you use one.

[Louis]

All this talk about AIs reminded me of this article about how the design used in most Western aircraft is likely to be partly responsible in causing accident's like the one Kennedy Jr. had.

http://www.aero.ca/e_kennedy%27s_spiral.html

Worth a look while we're on the topic.

Goodbye,

Louis

[trey kule]

CID-Oldtimer

I cant believe what I am reading. Bigsky gave an address...take a minute and click on it. Seems to me that should have been the end of this thread ...I never cease to be amazed by those who wont take a moment to look up what someone else posted.

As others continually point out....THEY ARE THE SAME THING.

[chubbee]

An artificial horizon is a self contained instrument An attitude indicator has an external source of info which it displays at a flight crew station. The behind the panel occupied space can be less for the AI.
Quibbles about trivia on this topic would seem to be harmless enuff. A lot of online references like Wikipedia are good for general knowledge on the quick but they can be kind of dumbed down. A distinction can be made between the two units, for the sheer joy of it all.
Is an altimeter an altimeter even when it is a servoed indicator requiring electricity to indicate rather than a clockwork marvel running directly on the expansion of a bellows? Yeah fuctionally it is to the pilot, but there is a difference in concept and execution behind the panel.

[CID]

As others continually point out....THEY ARE THE SAME THING.

No. They are not. Wikipedia is a good fast resource but it sometimes fails in the details. If I was so inclined, I could have it changed. I have been criticized in the past for making refernce to a Wikipedia article. So where is the criticism now?

chubbee is right. Modern airplanes and especially transport category airplanes typically have many remote sensors like air data computers, AHRS, INS, DG, VG etc. In such systems the "indicator" that sits in the panel is incapable of displaying the information on its own. This has prompted a change in the language and the development of different terms to better make the distinction between a dumb altitude indiator and a completely self contained altimeter.

Having said that, let's approach the subject from a purely pilot perspective. It doesn't matter what the hell you call it as long as you know what to do with the information. If you snag the "AI" or "ADI" or "AH" or "FD" any AME worth her salt will know that the problem could be with the attitude source or with the indicator. The pilot (rightly so) really doesn't care as long as it gets fixed.

[Hedley]

From a pilot perspective, who really cares.

However, it's worthwhile remembering that size matters. Yes, bigger really is better. Try it for yourself and see

[Thair81]

So let me get this straight- the AI and the AH are basically the same thing with the AH having the potential to be made into a more complicated and sophisticated instrument. Am I understanding this correctly?
I never thought that this topic would raise so much discussion, but there we go.

[trey kule]

Boy, is my face red. Years ago , in the 80's the "artifical horizons" in our aircraft were converted to "attitude indicators". I didnt notice the change but the bright young , newly minted pups to told me that what was in the plane was asn"AI". Looked the same to me. Maintainance guys swore they had not changed them. Now I am not doubting you guys...all this gyro differences and connections...wow, you guys really know your stuff.

So with that in mind, I beleived what I read on the web connection. to those who have explained the difference perhaps explain to me why I never, and I mean never, hear one of the new gel-hair-coat crowd refer to anything in any plane as anything but an AI? :oops: [/img]

[JigglyBus]

Chubee and CID... it seems that Sigmatek, Chief Avionics, and Aircraft Spruce are not aware of the 'facts' that you are stating. Perhaps you could call them and fill them in with your expertise.

Stand Alone AI for sale here.....
http://www.aircraftspruce.com/catalog/i ... andard.php

AI for Sale under 'Artificial Horizons' page....
http://www.chiefaircraft.com/Aircraft/F ... 00-411.jpg (self contained again, might I add).

Sigmatek clearly and freely interchanges the words Indicator and Horizon several times on this pages.....
http://www.chiefaircraft.com/cgi-bin/ai ... Gyros.html

I could go on and on with examples, but it's getting a little boring.

If you wish to call a stand alone one an AI, and a self contained one an AH, that's your prerogative. One thing it definitely isn't however, is a fact.

Tomayto, tomahto, potayto, potahto.

[chubbee]

The fine people south o the border don't spell colour with a u either! Whats up with that? None of this stuff is written in stone it varies by manufacturer & etc... Nomenclature that was standard 20 years ago undergoes evolution. Has anyone seen the blank look you get in the Carribean if you call electricity Hydro during a power interruption?

[Dust Devil]

As others continually point out....THEY ARE THE SAME THING.

No. They are not. Wikipedia is a good fast resource but it sometimes fails in the details. If I was so inclined, I could have it changed. I have been criticized in the past for making refernce to a Wikipedia article. So where is the criticism now?

Here's your critisism CID sorry I just got to the post now. Awwww @#$! it you know what I want to say.

[CID]

Chubee and CID... it seems that Sigmatek, Chief Avionics, and Aircraft Spruce are not aware of the 'facts' that you are stating. Perhaps you could call them and fill them in with your expertise.

JigglyBus,

Aircraft Spruce calls HSIs "Heading Situation Indicators". They are wrong. Maybe I SHOULD call them to set them straight.

http://www.answers.com/topic/attitude-indicator

[Hedley]

Just to confuse things further, weren't all the DG's (directional gyros) swapped out and replaced with HI's (heading indicators)?

[AggieLady79]

Apparently, there was a difference, at least 60 years ago. What brought me here was wanting more information after reading the Civil Aeronautics Board accident report on the February 3, 1959 crash of the Beechcraft Bonanza carrying Buddy Holly, J. P. "The Big Bopper" Richardson, and Ritchie Valens.

The report made reference to the difference between the two, and how it could confuse a pilot who was unfamiliar with the display of one vs. the other.

"When his instrument training was taken, several aircraft were used and these were all equipped with the conventional type artificial horizon and none with the Sperry Attitude Gyro such as was installed in Bonanza N 3794N. These two instruments differ greatly in their pictorial display.

The conventional artificial horizon provides a direct reading indication of the bank and pitch attitude of the aircraft which is accurately indicated by a miniature aircraft pictorially displayed against a horizon bar and as if observed from the rear. The Sperry F3 gyro also provides a direct reading indication of the bank and pitch attitude of the aircraft, but its pictorial presentation is achieved by using a stabilized sphere whose free-floating movements behind a miniature aircraft presents pitch information with a sensing exactly opposite from that depicted by the conventional artificial horizon. . . .

"Service experience with the use of the attitude gyro has clearly indicated confusion among pilots during the transition period or when alternating between conventional and attitude gyros. Since Peterson had received his instrument training a in aircraft equipped with the conventional type artificial horizon, and since this instrument and the attitude gyro are opposite in their pictorial display of the pitch attitude, it is probable that the reverse sensing would at times produce reverse control action. This is especially true of instrument flight conditions requiring a high degree of concentration or requiring multiple function, as would be the case when flying instrument conditions in turbulence without a copilot."

From: https://en.m.wikisource.org/wiki/Aircra ... %27s_crash

[PT6-114A]

I was told some long time ago that the term “artificial horizon” was not correct as you can’t see yaw hence forth call it an “Attitude indicator” seemed to make sense to me.

[digits_]

I was told some long time ago that the term “artificial horizon” was not correct as you can’t see yaw hence forth call it an “Attitude indicator” seemed to make sense to me.

How would one see yaw on a real horizon?

[Thair81]

15 years after I asked the question initially and the debate has started up again. Impressive. Glad the old question can still generate a bit of thought and discussion.

This has got to be some sort of record for this “esteemed” message board.

[‘Bob’]

I was told some long time ago that the term “artificial horizon” was not correct as you can’t see yaw hence forth call it an “Attitude indicator” seemed to make sense to me.

How would one see yaw on a real horizon?

By looking at the terrain features moving sideways.

But maybe they didn’t have synthetic vision a long time ago.

[digits_]

I was told some long time ago that the term “artificial horizon” was not correct as you can’t see yaw hence forth call it an “Attitude indicator” seemed to make sense to me.

How would one see yaw on a real horizon?

By looking at the terrain features moving sideways.

But maybe they didn’t have synthetic vision a long time ago.

That could be a crosswind as well.