What is the deal with tapes?

Okay, I've been watching the transition to glass cockpits
in GA aircraft.

Clearly, the cost savings and simplification that comes from
integration is neat, and the reliability of an all-electrical
system is (probably) going to mean more safety for all of us.

But one thing bugs me -- the tapes.

I can't for the life of me figure out what all the manufacturers
have opted to provide flight information in these electronic
tape formats. Has this been proven to be more effective, more
ergonomic, easier to interpret, etc?

My impression is that it is just the opposite, and I thought
that there was some research out there to back me up -- that
seeing the position of a needle, or in the case of a straight-
and-level flight or any stabilized maneuver, noticing movement
of a needle seems a lot easier to me than reading a tape,
understanding the number it displays, and thinking about whether
that number is the same as the last time you looked at it, etc.

I don't think it's a huge problem of course; it's totally
reasonable that a pilot will remember his altitude from one
moment to the next, but I do think there is some delta there.

I've noticed also, that the AI is drawn like an AI, mostly, and
that HSIs are drawn like HSIs -- an analog representation if
there ever was one. Engine instruments mostly are presented as
analog dials, with digits underneath them.

It's really only the airspeed, altitude, and vsi that suffer
this fate.

Why don't they just draw pictures of the round dials? Or at
least give the pilot the option? I suspect that back when
these displays were new, there wasn't room for round dials.
But with 10+ inch hi-res displays, there sure is now.

Opinions?

-- dave j
-- jacobowitz73 --at-- yahoo --dot-- com

PS -- I work in high tech; I like computers a lot, I'm not a
luddite. I just wonder if there is real human-factors based
support for the tape representation, or if it's just a "cool"
factor thing.

(Dave Jacobowitz) wrote in
om:

But one thing bugs me -- the tapes.

I can't for the life of me figure out what all the manufacturers
have opted to provide flight information in these electronic
tape formats. Has this been proven to be more effective, more
ergonomic, easier to interpret, etc?

Fly with the tape presentation awhile before you start worrying. With a
tape, you can see the height and the relationships between tapes at a glance,
without having to worry about where a needle is pointing. As long as the tape
is green, you're in good shape, but if it turns red, then you know
immediately that you've reached a limitation. If all you've ever seen is a
dial, then you probably prefer a dial. But if you get used to tapes, then
you may prefer it.

--
Regards,

Stan

You can also get a good feel for the trend of the tape by how fast/slow it's
moving in any given direction. J. Mac McClellan wrote about tapes in a
recent column in Flying (he likes tapes but he was complaining about the
lack of speed markers). Tapes are no doubt the result of many studies by
NASA and other entities (DARPA maybe?) so I would see if you could dig up so
info on their line of thinking.

Marco Leon







"Stan Gosnell" wrote in message
...
(Dave Jacobowitz) wrote in
om:

But one thing bugs me -- the tapes.

I can't for the life of me figure out what all the manufacturers
have opted to provide flight information in these electronic
tape formats. Has this been proven to be more effective, more
ergonomic, easier to interpret, etc?

Fly with the tape presentation awhile before you start worrying. With a
tape, you can see the height and the relationships between tapes at a
glance,
without having to worry about where a needle is pointing. As long as the
tape
is green, you're in good shape, but if it turns red, then you know
immediately that you've reached a limitation. If all you've ever seen is
a
dial, then you probably prefer a dial. But if you get used to tapes, then
you may prefer it.

--
Regards,

Stan

In article ,
says...


I thought the idea of the tapes was to have a "one-stop" instrument scan
(or almost), rather than having to zap back and forth between different dials
to construct a picture of the situation. After all, you're probably used to
using the little GS indicator on your HSI, if you have one, rather than having
to include the more distant VOR indicator in your scan.

Human factors specialists have written a lot about which instruments are more
"intuitive" to read. They complain about the plain old attitude indicator,
because it violates the basic rule that the moving parts of the instrument
should move in the same direction as the related control inputs.

I have read that tapes are less intuitive to read than dials - with the
obvious comparison being a classic clock compared with a digital display. But
then, it is drilled into us that we are not supposed to read the instruments
"intuitively" - we are supposed to read, and deliberately "interpret" the data
before deciding what action to take. One could almost argue that the more
"intuitive" display detracts from the objective of flying by the numbers.

The latest issue of FLYING has an article on the subject by MacLellan, in
which he discusses the use of the tapes with regard to reference speeds and
bugs.

G Faris

Dave Jacobowitz wrote:
I can't for the life of me figure out what all the manufacturers
have opted to provide flight information in these electronic
tape formats. Has this been proven to be more effective, more
ergonomic, easier to interpret, etc?

You might find this article of interest:

http://www.sciencedaily.com/releases...1013084121.htm

It suggests that needles and dials may in fact be better.

The conventional round altimeter has the problem that between 0 and 500 feet
the pointer moves down as the altitude increases. Then, from 500 feet and
1000 feet the pointer moves up as the altitude increases. I think a tape is
a better presentation because it always moves in the same direction
irrespective of altitude.

The conventional round ASI has the same problem as the altimiter.

The pointer on the conventional round VSI moves in the correct direction
until it reaches the 12:00 or 6:00 position, then it reverses.

Good thing most pilots aren't easily confused. Unfortunately, I am easily
confuzzed.

Jon

Okay, I've been watching the transition to glass cockpits
in GA aircraft.

Clearly, the cost savings and simplification that comes from
integration is neat, and the reliability of an all-electrical
system is (probably) going to mean more safety for all of us.

But one thing bugs me -- the tapes.

I can't for the life of me figure out what all the manufacturers
have opted to provide flight information in these electronic
tape formats. Has this been proven to be more effective, more
ergonomic, easier to interpret, etc?

Many man-centuries of effort has been expended in the research of flight
instrument presentation, and I won't pretend to be an expert in all of it,
but I do have some knowledge and experience in the area. No its not
conclusively better, but does has some advantages and disadvantages. Your
instrument scan is smaller with tapes, but its harder to see trend movement.


My impression is that it is just the opposite, and I thought
that there was some research out there to back me up -- that
seeing the position of a needle, or in the case of a straight-
and-level flight or any stabilized maneuver, noticing movement
of a needle seems a lot easier to me than reading a tape,
understanding the number it displays, and thinking about whether
that number is the same as the last time you looked at it, etc.

Yes, but years of flying with tapes in business jet, regional, and air
transport should tell you something too. It's an acceptable way to present
the information, and the pilot can be trained to effectively use it.


I don't think it's a huge problem of course; it's totally
reasonable that a pilot will remember his altitude from one
moment to the next, but I do think there is some delta there.

I've noticed also, that the AI is drawn like an AI, mostly, and
that HSIs are drawn like HSIs -- an analog representation if
there ever was one. Engine instruments mostly are presented as
analog dials, with digits underneath them.

It's really only the airspeed, altitude, and vsi that suffer
this fate.

Why don't they just draw pictures of the round dials? Or at
least give the pilot the option?

Certification cost, development effort, desire to minimize menu selection
and install options.

I suspect that back when
these displays were new, there wasn't room for round dials.
But with 10+ inch hi-res displays, there sure is now.

Actually that's not true. The reason they are tapes is because attitude is
the most important instrument and its presentation needs to be the most
emphasized. There is simply not room to have the big attitude indicator and
round dial pitot static instruments. Minimizing display clutter is
important too, and some vendors have chosen to minimize the impact of the
ASI and altimeter on the attitude indicator by using tapes. Even the tapes
themselves can be translucent so you see right through them to the attitude
indicator colors. To make up for the deficiencies of tapes, there are
features like trend indicators, colors, prominent V speed markings, and
others. Compare Avidyne's and Garmin's to some that do have round dials
like this one http://www.rogersonkratos.com/mfd.html or the Collins MFD-268
and see how either attitude indicator shape is affected or has to be
smaller.

GA pilots generally don't like tapes as much at first, but can and do get
used to them.

Dave Jacobowitz wrote:
Okay, I've been watching the transition to glass cockpits
in GA aircraft.

Clearly, the cost savings and simplification that comes from
integration is neat, and the reliability of an all-electrical
system is (probably) going to mean more safety for all of us.

But one thing bugs me -- the tapes.

I can't for the life of me figure out what all the manufacturers
have opted to provide flight information in these electronic
tape formats. Has this been proven to be more effective, more
ergonomic, easier to interpret, etc?

My impression is that it is just the opposite, and I thought
that there was some research out there to back me up -- that
seeing the position of a needle, or in the case of a straight-
and-level flight or any stabilized maneuver, noticing movement
of a needle seems a lot easier to me than reading a tape,
understanding the number it displays, and thinking about whether
that number is the same as the last time you looked at it, etc.

I don't think it's a huge problem of course; it's totally
reasonable that a pilot will remember his altitude from one
moment to the next, but I do think there is some delta there.

I've noticed also, that the AI is drawn like an AI, mostly, and
that HSIs are drawn like HSIs -- an analog representation if
there ever was one. Engine instruments mostly are presented as
analog dials, with digits underneath them.

It's really only the airspeed, altitude, and vsi that suffer
this fate.

Why don't they just draw pictures of the round dials? Or at
least give the pilot the option? I suspect that back when
these displays were new, there wasn't room for round dials.
But with 10+ inch hi-res displays, there sure is now.

Opinions?

-- dave j
-- jacobowitz73 --at-- yahoo --dot-- com

PS -- I work in high tech; I like computers a lot, I'm not a
luddite. I just wonder if there is real human-factors based
support for the tape representation, or if it's just a "cool"
factor thing.

I think its more about getting the maximum information in the
minimum space. Dials take up room, even on a virtual display.
Every study probally shows that simple digits are non-intuitive.
Tapes integrate well with lots of other things going on in the
display.

The long term goal seems to be to have two instruments, the HSI
and a "VSI" or Vertical situation indicator, which is what the
attitude gyro is evolving into.

I suspect dials are better if you have the room. They allow the
entire scale to be placed on the display at once.

--
Samiam is Scott A. Moore

Personal web site: http:/www.moorecad.com/scott
My electronics engineering consulting site: http://www.moorecad.com
ISO 7185 Standard Pascal web site: http://www.moorecad.com/standardpascal
Classic Basic Games web site: http://www.moorecad.com/classicbasic
The IP Pascal web site, a high performance, highly portable ISO 7185 Pascal
compiler system: http://www.moorecad.com/ippas

Good does not always win. But good is more patient.

G Farris opined

In article ,
says...


I thought the idea of the tapes was to have a "one-stop" instrument scan
(or almost), rather than having to zap back and forth between different dials
to construct a picture of the situation. After all, you're probably used to
using the little GS indicator on your HSI, if you have one, rather than
having to include the more distant VOR indicator in your scan.

Human factors specialists have written a lot about which instruments are more
"intuitive" to read. They complain about the plain old attitude indicator,
because it violates the basic rule that the moving parts of the instrument
should move in the same direction as the related control inputs.

The human factors people are probably correct, but how does one change the
real horizon to conform with their desires?


-ash
Cthulhu in 2005!
Why wait for nature?

In article , Fox Hound
wrote:

Many man-centuries of effort has been expended in the research of
flight instrument presentation

Indeed.

Your instrument scan is smaller with tapes, but its harder to see
trend movement.

That's true, although that issue can be somewhat overcome.

For instance, the B744 PFD displays a speed tape, but also has a green
trending arrow to show both magnitude and direction for a prediction of
the speed in 10 seconds from now based on current rate of change.

Obviously, it's not always perfect -- will always be some situations
where you have a sudden large displacement that isn't indicative of
where you will be in 10 seconds from now. But as a whole, it's generally
very accurate.

In use, it seems to be pretty effective for dampening some of the PIO
issues, though I'm sure that more experienced flight crew members won't
even need to see the trending information to anticipate appropriate
flight control response for any given situation.

It won't ever replace the VSI, but it'll give a reasonable off-the-cuff
quick and visual look at trending data without having to spend much time
mentally number-crunching things. Very useful in high workload situations.

If I recall correctly, Airbus EFIS displays takes Human Factors (HF)
design to the next level and presents the data very darned well. Makes
even greater use of colo[u]rs but to good User Interface (UI) effect.

I'm more familiar with the Boeing EFIS design, so I had to pay more
attention to various seemingly subtle (but really important) features of
the Airbus EFIS displays.

Anyway, I can certainly see the pros and cons for both style of gauges.

Just saying that the issues with tapes can be overcome effectively.

-Dan