So you might change one jet size per 2000 - 3000 feet?
DA = Density Altitude. I was wondering the same thing so don't feel alone.
It seems like everywhere in the world people assume we know the acronyns
or initialisms automatically. It is always handy to identify them at first use.
Doing so takes a little more time, but will save everyone more time in the
long run. For example, when writing about Density Altitude (DA) after this
first use we'd just abbreviate it DA and all would know.
Once I new what DA was I could then search for an article;
I'll burn through it when I get the time.http://www.hotrod.com/techarticles/engi ... ewall.html
I didn't have to wade through links for District Attorney and others.
AWACS (Airborn Warning And Control System) is similar.
But glad we know that EFI is Electronic Fuel Injection and
MTBF which is Mean Time Between Failure. The last two are
pretty important to racers and auto entheusiasts.
Also for us old timer's we know that NACA is the forerunner to NASA;
that is, NACA - National Advisory Committee for Aeronautics and
NASA - National Aeronautics and Space Administration.
Here is a link that has the same problem just described.
When looking for a link to a NACA duct, NASA is not defined
in the same article.http://en.wikipedia.org/wiki/NACA_duct
Here is a link I found that explains it from Hot Rod,