Digital meters 3

"Ian Mitchell" wrote in message
...

wrote in message
oups.com...
I appreciated many freinds attend discuss digital meters.
In fact, we are interesting in digital meters. First we know most of
pilot liking analog meter with many friends help. I forwarded your
replies to our engineer.
Our engineer told me we should do two kinds of meter, one is flight
meters, second is engine meters.
Filght meter include: ALT, VSI, ASI, Horizon Gyro. Except gyro, these
vales are showed in analog display digital.
Engine meter: CHT, EHT, RPM, TEMP. PRESSURE,HOURS, FUEL CONSUME, VOLT.
AMP. They are showed in numeric display digital.


Just an observation, as a pilot, I can tell you that I generally am not
interested in the absolute value of temp, pressure etc. What I need to
know is that the reading is in the green arc, ie it's within an acceptable
range. That to me represents the atvantage of traditional instruments over
digital, I can tell at a glance in a rapid instrument scan what the
current situation is. Another advantage is that I can do it with
peripheral vision, and keep my attention where it needs to be, ouside the
cockpit.


The other thing I get with the old style analog meters is a quick estimate
of "rate of change." In a quick glance at the gage I can see WHERE the
needle is and if it is moving, how fast it is moving, and in what direction
its moving. That rate information makes a great difference in my response
to the meter reading!

With a digital readout the lower order digits are often flickering. I can't
tell how fast, or which way, or even if they are just jittering back and
forth a bit with out concentrating my attention on the readout for several
seconds. That is enough to totally blow my instrument scan and blow away my
internal integration my data streams from my instruments. I know from
experience that the worst thing I can do while flying on instruments is to
focus my attention on any one instrument. I have to constantly compare the
different gages that give me overlapping information for agreement. If any
two instruments that give me the same information from different
perspectives or techniques disagree, instantly my instruments are suspect
and I have to cross check until I indentify which one is lying to me and
then ignore it in my subsequent scan. If I fail to do that I will likely
kill myself when the vacuum pump fails or when the power goes bye bye. I
have had both vacuum and electrical systems fail more than once when flying
in solid IFR but I have NEVER had both systems fail at the same time! That
difference is why I am still here blathering on the internet! :-)

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

PS: The Pinckneyville r.a.h. flyin is coming up May 19, 20, 21. Be there
or be square! Email Mary at and let her know you are
coming so she can arrange for the groceries. Saturday night dinner is
steak, baby back ribs, or chicken breast. Let her know you preference. We
are leaving town right after the flyin and don't want a lot of leftovers to
deal with! :-)