stage 2 vs stage 3
 

These terms are noise related, but what are they?
is stage 2 the same as chapter 2,if so what does it mean?

thanks

That is a difficult question. The answer depends on who you ask. Stage 2 and Chapter 2 are relatively the same worldwide. Stage 3 Chapter 3 are slightly different. The noise level requirements are roughly the same, but the way of recording and analyzing the data are not. Mostly due to the fact that them damn Europeans like to change the rules of the game after it has started and isn't panning out to their liking. Sorry to the EU people. :)

different standards ..... ICAO and FAR

As I understand it the main difference is over "trading". In the US system if an aircraft is over on one of the measurements and under on an other there can be a trade off. In the euro rules the aircraft must pass all the tests separately.

At the moment the big issues is what will happen in Stage 4. If the final compromise is
to weak then we will end up with the airports both in US (ie Orange county) and
Europe (ie Frankfurt) setting there own and different standards. This is when the real
fun starts.