wrote in message
ups.com...
On Oct 6, 9:21 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

You'll get used to it... there is a transition time to go from round
dial to tapes, but once you get used to tapes you will find that they
do have certain advantages. I worked on the 777 EFIS, which used the
tape format, and after several hours in the 777 simulator, the tapes
became as easy to read at a glance as the round dials. It just takes
conditioning your mind to be able to rapidly scan them, and being able
to pick up trend information from the tape motion instead of needle
motion. At least that was my experience.

A lot of human factors work went into the tape formats, and it was
with the understanding that training would be required for pilots to
adapt to them.

Dean

I have never seen the system for the 777, but I did get a look at the low
end equipment at the LSA Expo in Sebring Florida, and felt that what I saw
was pure crap!

It is certainly possible to make a tape motion system that works well, and I
have seen some "physical" versions that I liked when I was an avionics tech
twenty years ago. However, those have a moving needle which moved in
opposition to the moving tape and at a slower rate than the tape. The
result was that the needle gave the coarse indication, at a glance, and the
tape gave the precise measurement when required--and, in the case of a
higher flying aircraft which would require a three needle altimeter, may
have been more intuitive to read.

However, on the implementations that I have seen, the representations of
needles were fixed and the numbers moved on a virtual card or tape. In my
opinion, they were egregeous!

Peter