In article , Robert
Moore wrote:

If you are not assigned FL180 why would you want to know when you
are passing it in a climb?

So you know when you reset your altimeter so you don't go through the
190 you were assigned. A few years back we had a day with an absurdly
low local altimeter setting (something like 29.02).

We were climbing to FL190, so as we're passing through just under
18,000 feet and climbing like a bat outta hell, I whirl the altimeter
up to 29.92 to find we (ahem...) almost climbed through our altitude.
There were only 200 feet between 17,900 feet and FL190. Quite an eye
opener, to say the least.

--
Garner R. Miller
ATP/CFII/MEI
Manchester, CT =USA=