Well, it is about 3 to 4Hz (3 to 4 full swings from -250 to +250 FPM
or the other way per second). You basically can't track it. (Other
than approaximate its "main value", which is about 0 fpm.

The ALT basically fall back to 6000 ft (assigned altitude) after swing
to the high point (6200 ft) so you can see where you at without a
problem.

No obivious change to ASI...

No alternate air on this old 172, the ASI has MPH instead of KtH. But
it is a nice plane.

(Teacherjh) wrote in message ...

If an altimeter is going through 400' of altitude change in 250ms, that
is definitely fast.


Yes, but not too fast to see.

Jose