That's exactly what I'm talking about. My understanding was that if you
have been cleared to maintain 3000 feet, and you dip down for example
past 2800' then it's a violation. A friend heard that it's actually 100
feet, which would incur a violation passing 2900 feet going by my
previous example.

Is there some reliable source of information where this info can be found?

On 2004-03-20 22:16:00 -0500, "Steven P. McNicoll"
said:


Depends what you mean by "violated". If your Mode C altitude is within 200
feet of your reported altitude you're considered to be on altitude.