If the static source is blocked, the instrument which will over read in a descent is
[a] altimeter.
[b] airspeed indicator.
[c] vertical speed indicator.
[d] artificial horizon.
I understand ASI would over read, but what about altimeter. It will stuck at the original height, hence over read as well??
This question comes up occasionally.
It depends on your definition of 'over reading'. If the altimeter were over reading, it would be giving consistently higher readings than the actual altitude. So as altitude changed, the altimeter would be changing its indications but they would always be higher than the actual altitude.
If the static source was blocked, the altimeter reading would be fixed at the height at which the blockage occurred. It would simply be unserviceable. You couldn't call that over reading.
