Maybe instrument design has changed, but I recall the counter, drum, pointer
altimeter needing a vibrator (read battery consumption) to keep the pointer
and digits from sticking. Or you could continuously tap the panel to keep
it moving...

"Bill D" wrote in message
...
On Tuesday, January 15, 2013 5:15:40 PM UTC-7, Craig R. wrote:
If I remember correctly, studies were done on the ability of the brain to
interpret and understand data quickly using either an analog or digital
readout. Time and speedometer readouts were the main emphasis of the
study. The study showed that the brain interprets the analog display
quicker and with greater accuracy. Besides the issue of running out of
power, it appears that the analog display is superior to digital for
information gathering and execution. Something to consider in going to an
all glass panel. Perhaps someone that is up on this subject could
elaborate?

That study was done very early in the digital age - 1960's IIRC. Current
studies show that while it remains easier to detect a trend with an analog
needle, a discrete value is easier to read in digits. Few would use an
altimeter to detect a trend so it works best as a numeric display which is
why few high performance aircraft use 3-hand altimeters anymore - in fact
they're pretty much relegated to gliders which means they're probably going
to disappear. Not many "little old Swiss watchmakers" left to fix them these
days.