When ever ATC says “Climb and Maintain…” or “descend to…”, what VS should I use? They never specify it.
For descending, I usually calculate it based on the 3° descent formula (VS=1000xMachx3).
Also, ATC doesn’t have the option to specify. Just have a reasonable VS, and you’ll be fine.
Take a look around the radar first as often times they will give you a long approach. Going from 12k to 4k for example. If you are 40 miles out you don’t want to drop -3000 VS. Try to visualize where they are putting you and use the altitude “banana” that shows on the radar as a gauge. Keep an eye out for other traffic and adjust accordingly.
I utilize the approach Capt Joe recommended. To maintain a 3 degree descent rate he suggests Multiplying your ground speed by 5. To slow down and shallow your descent when approaching FL100 he suggests multiplying G.S. by 3.6 to find out your VS to descend at.
Just feel around. Think about your speed, size of your aircraft etc. You don’t want to be in a 172 and descending at -3000 but you don’t want to be in an A320 and descending at -1000. Really up to you.
Use common sense with you’re 25nm at 7500ft in 15nm need to drop 3500ft just slow down use a good vs which is around 1100vs-1900vs simple. Also there’s some math you can do like the others have slowed above!
Good Day :)
It actually doesn’t matter what VS you use, so long as you get to ATC-instructed altitude, whether ascent or descent. As @elcapitan1 suggested, be realistic with VS. Don’t descend at -3000 VS in a Cessna 172 or be descending in an A320 at -1000.
I normally climb or descend 2000 VS