CDA's
Well by defenition a constant descent approch is just that, one without any level flight.
Although I do believe it only applies below a certain level, and is defined as a minimum vertical speed throughout the manoeuvre. however my challenge to myself is to not touch the thrust levers, apart from guarding them! until we are fully established and need to spool up for the landing, usually about 8nm or so as we get asked to do 160kts to 4dme, which needs flaps 20 and some power to maintain it....
that said its a great feeling when it does work out and you dont need to touch the thrust levers until you need to spool up.... big smug grin on face at that point.....
When were given track miles can vary greatly between airports flown into, we went into LBA the other day and at FL90 were told 20 miles to run by a new controller i think, bearing i mind we were still doing about 250kts... but then thats what the speedbrakes for isnt it....
It all adds to the excitement, however flying a 757 on FL CH against the speedbrake can produce some pretty impressive rates of descent.