For descent and speed - North America's ATC will often specify...
"Expediate descent and maintain 8,000 feet, speed 230. Altitude first then speed".
That airspace is a paradise. Sorry for the guys in W. Europe...
Ask your ATC what they want first...
xxx
In the 747, level flight, reducing 340 to 250 takes... 9 NM (340-250=
90 NM).
Or 300 KIAS down to 250 KIAS = "
50" or... 5 NM.
Works in other planes too. Worked in the 727, certainly will do in a 737.
And dont forget your gear - Your best brakes...!
xxx
Happy contrails