On Oct 6, 1:51 pm, Bertie the Bunyip wrote:
Phil wrote in news:1191696116.820241.83540@
19g2000hsx.googlegroups.com:







On Oct 6, 10:21 am, Arno wrote:
Hello,

I am computer scientist and usually really like fancy technology. But
I just had my first flight with a "glass" PFD (Avidyne) and must say
I
am not impressed. In particular reading altitude and airpeed from
these scrolling bands requires a lot more attention than with regular
gauges, just like reading a digital clock takes longer than reading
an
analog one. Glancing at it and checking against a known picture, like
"speed at 3 o'clock is fine on final" or "altitude at 20 minutes past
midnight is minimum", just does not work anymore, instead I end up
reading the actual numbers every time I look. Does anyone feel the
same? Am I missing a particular technique?

Arno

I am a fellow computer geek, and a student pilot. I usually fly a
plane with steam gauges, but a couple of times now I have flown with
digital displays. Like you, I found it a little hard to adjust to the
digital displays. The digital displays I was using presented altitude
and tachometer values simply as numbers. The analog displays I am
used to present these values as positions on a dial, showing the
current value in its context of a spectrum of values. With the analog
displays, I am used to adjusting the position of the pointer. With
the digital display, I need to simply set the correct numerical
value. It's a little mental adjustment, and given that I am a newbie
to all this it is an extra distraction.

But, I do think that it is mostly a matter of what you are used to.

Flying is a right hand brain activity. At least the handling portion is.
The right hand side of the brain dosn't do abstractions like numbers, at
least not until the left hand side (which can't fly worth a ****) sends
it over to the right side in a readily digestable form which enables the
right brain to chew it into a picture.

An analogue display cuts the left hand side out of the loop and enables
the calcualtion rate to increase the right sides "frame rate" so that
corrections can be made more frequently thus enabling the pilot to fly
the airplane more smooothly and with more authority.
Caorse rule of thumb math can be laid over this for descent angles,
interceptin angles and wo on, but generally, the fewer numbers involved,
the better.
People who prefer the numbers usualy don't fly very well at all.

You don't do trig while you're shooting pool and expect to win the game.

Bertie- Hide quoted text -

- Show quoted text -

As I understand it, the whole right-brain left-brain thing has pretty
much been discredited. The more recent research shows that any
complex task engages both sides of the brain. I don't think there
were too many neuroscientists who ever embraced the idea that one side
does "art" and the other side does "math" anyway.

I think the biggest difference between steam gauges and digital
displays is that steam gauges give you a value in context of a
spectrum of values. When you look at a analog tachometer, you can see
the where the needle is compared to the minimum and maximum values.
If you are trying to set 75% power, it might be useful to have the
information presented that way, because you can see where 3/4 of the
range is. Same with airspeed. You can see how close you are to the
red arc, where you are in the green arc, etc.

On the other hand, why would you want to see altitude displayed with
needles? If I want to fly at a specific altitude, I am looking for a
number, not a position in a range. I think the traditional altimeter
was made the way it was because it was the easiest way to get a
mechanical instrument to display the information that way, not because
it was the easiest way to digest the information.

Ideally, every instrument should be designed to convey the appropriate
information in a way that is conducive to how that information is
going to be used. If you just need a value, then a digital display of
a number make sense. If you need to have a sense of where you are
relative to minimum and maximum, then a display showing relative
position in a range should be used. The nice thing about a
computerized display is it can be set up to display the information
either way.

Phil