Cool attitude indicator

Everyone has seen those "Laser Levels" advertised on TV. I own one,
and (although it's relatively useless) it's very cool.

Wouldn't it be slick to have a gyro-stabilized thin red line projected
onto your panel, graphically displaying the actual horizon? Talk about
situational awareness in the 21st century! You would have to be blind
not to see which way was up...

This sounds like science fiction (or, at least, it did to me) -- so
imagine my surprise when I found that this very system was used in the
SR-71 Blackbird -- a plane that was designed and built over 40 years
ago.

Who'd a thunk it?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

The AI is an instrument that's overdue for better human engineering.

Almost everyone's had a moment of confusion figuring out which way the
plane was banking, because of the way the horizon moves but the
airplane "wings" stay level.

I believe NASA's done studies showing that if you simply had the
current AI's "wings" tilt towards the side you were turning, pilots had
no problem instantly understanding their situation.

I seem to recall ads in old magazines pushing a visual horizon line on
the windshield such as you described. I think this was pre-laser.

I also saw a neat AI from the '60s on eBay that actually had a little
dome protuding towards you, with a tiny model airplane inside. If you
were banking / diving the little plane was too. Very cool.

Cheers, Kev

In a previous article, "Kev" said:
The AI is an instrument that's overdue for better human engineering.

Almost everyone's had a moment of confusion figuring out which way the
plane was banking, because of the way the horizon moves but the
airplane "wings" stay level.

Russian/Soviet AIs do the opposite - the horizon line is fixed and the
little airplane moves. It must be very confusing for people who had to
switch between "our" sort and "those" sort or back the other way.


--
Paul Tomblin http://xcski.com/blogs/pt/
....would you work for a company that couldn't tell the difference in
quality of its employees' normal work product and the work product of
someone on drugs without performing a test? -- socks

Kev wrote:

I believe NASA's done studies showing that if you simply had the
current AI's "wings" tilt towards the side you were turning, pilots had
no problem instantly understanding their situation.

The very first AIs, then developed in Germany, worked that way, and
studies seem to imply that it's more intuitive. This design is still in
use in the countries of the former soviet union and their region of
influence. The AI as it is known in our part of the world was designed
by Sperry, IIRC, and I think it was at least partly a matter of
copyright to do it the way they have.

Pilots who were trained in eastern Europe and then are hired by western
companies have to be retrained, which is extremely difficult. In a
stress situation, you allways tend to fall back to the procedures
learned in primary training. There was at least one airliner crash which
was the direct result of this: Easterly trained pilots flying a westerly
equipped plane with inadequate training, consequently misinterpreting
the AI in a situation of high workload. The report is well worth a
reading: http://www.bfu.admin.ch/common/pdf/1781_e

Stefan

On Sun, 10 Apr 2005 20:26:14 +0200, Stefan
wrote:

Kev wrote:

I believe NASA's done studies showing that if you simply had the
current AI's "wings" tilt towards the side you were turning, pilots had
no problem instantly understanding their situation.

The very first AIs, then developed in Germany, worked that way, and
studies seem to imply that it's more intuitive. This design is still in
use in the countries of the former soviet union and their region of
influence. The AI as it is known in our part of the world was designed
by Sperry, IIRC, and I think it was at least partly a matter of
copyright to do it the way they have.

Pilots who were trained in eastern Europe and then are hired by western
companies have to be retrained, which is extremely difficult. In a
stress situation, you allways tend to fall back to the procedures
learned in primary training. There was at least one airliner crash which
was the direct result of this: Easterly trained pilots flying a westerly
equipped plane with inadequate training, consequently misinterpreting
the AI in a situation of high workload. The report is well worth a
reading: http://www.bfu.admin.ch/common/pdf/1781_e

I have a buddy with a PhD in human-factors engineering (Purdue). I
gather from him that the phenomenon of figure-ground reversal as it
relates to flight instruments has been studied to death through the
years, There must be a couple of standard texts. I'll ask him the
next time I talk to him if I don't have a brain-fart.

I also imagine there's a lot of documentation at the Air Force Flight
Test Center at Edwards, but it's probably hard to search for.

Don

In article .com,
"Jay Honeck" wrote:


This sounds like science fiction (or, at least, it did to me) -- so
imagine my surprise when I found that this very system was used in the
SR-71 Blackbird -- a plane that was designed and built over 40 years
ago.

Who'd a thunk it?

From looking at this picture I wouldn't have:

http://www.sr-71.org/photogallery/bl...17976/cockpit/

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

On Sun, 10 Apr 2005 11:17:44 -0800, Dale wrote:

Following up my own post, here's the first google hit on the terms:
'figure ground reversal 'artificial horizon'." It's a six page report
on a study at the USAF Academy.

http://atlas.usafa.af.mil/dfem/resea...er-30-Self.doc

Don

"Kev" wrote in message
oups.com...
The AI is an instrument that's overdue for better human engineering.

Almost everyone's had a moment of confusion figuring out which way the
plane was banking, because of the way the horizon moves but the
airplane "wings" stay level.


Regardless of the form of the instrument, there will always be a "momentary
confusion".

There are two mismatched lines... one "moving" and one "fixed". No matter
which form of AI is used, there is ALWAYS "momentary confusion" until we
understand WHICH ONE is it that our control input will affect correctly (to
bring into alignment with the other).

I believe NASA's done studies showing that if you simply had the
current AI's "wings" tilt towards the side you were turning, pilots had
no problem instantly understanding their situation.


I suppose that depends on how you teach pilots their relationship to their
environment.

If pilots feel themselves "fixed inside" the AIRPLANE, oriented in space the
same as is the airplane, then it makes more sense that they will feel at
ease "controlling" the FIXED line and matching it to the movable one.

If they feel themselves to be fixed relative to the earth, and therefore
controlling the aircraft from "outside", like a video game or an RC model,
they will feel at ease controlling the MOVABLE line to match it to the fixed
one.

I have flown an aircraft, and I have flown a model. In both cases I have had
no trouble understanding which "line" I had to control, but also in both
cases I have experienced that momentary "confusion".

I could be wrong but....
....I would think that from an unusual attitude in VMC, a pilot's first
reaction would be to try align his dashboard (fixed relative to pilots
vision) with the horizon (movable relative to pilot's vision). Why this
should be different in IMC, requiring the opposite form of AI, you can
explain to me.


By the way, I am assuming that Jay really meant to have his laser line
projected onto the windshield as a HUD, not onto the panel.... on the panel
its just an wider version of the current AI, isn't it???

"Kev" wrote in message
oups.com...
The AI is an instrument that's overdue for better human engineering.

Which is why ADAHRS is coming on so fast.

"Don Tuite" wrote in message
...
On Sun, 10 Apr 2005 11:17:44 -0800, Dale wrote:

Following up my own post, here's the first google hit on the terms:
'figure ground reversal 'artificial horizon'." It's a six page report
on a study at the USAF Academy.

http://atlas.usafa.af.mil/dfem/resea...er-30-Self.doc

Don

From your google list, is this interesting research by the Canadians:

http://www.ainonline.com/Departments...ar04.htm#jan04

....and it was purposefully done in a real airplane instead of a desk
simulation...

I wish he had supplied pictures...