OK Scott, but you must be careful with your words - to do 500fpm in a jet, you'll need plenty of thrust - again, you won't be 'floating' down.
We've also hit on a human factors problem, especially in Europe. It usually goes like this.....
ATC 'Blockhead 123, what is your Mach number?'
B123 'decimal 83, Blockhead 123'
ATCX 'roger'.
Now, in lots of Europe where English is not the first language, doubt will exist as to whether Blockhead 123 must now maintain .83 or is still on 'free speed'. Similarly with requests to 'say your heading' which are not folowed by 'roger, radar heading, or 'continue present heading until advised'.
Here, ATC need to tighten up their phraseology, or clarify things by saying, for example, 'for my information, say your heading', followed by 'roger, own navigation to ABC VOR'.
Clarity is vital (even here on PPRuNe), so let's make ourselves understood.
