Steven P. McNicoll wrote:



It does rotate, just rather slowly. It tells you when you're over 10,000
MSL.


Nope. The hatch marks are painted on the same face that the big numbers
are painted on. They are stationary. The disk that supports the 10,000
ft pointer, and has the letters ALT painted on it, has a "window" cut
out of it, that will slowly cover up the hatchings as elevation
increases. At 10,000 ft, about 75% of the hatch marks are obscured. I
think this is to aid in visually identifying that you have reached the
tens of thousands of ft. elevation.

Happy Flying!
Scott Skylane