Capt Fathom
Join Date: Jun 2001
Location: FNQ ... Still!
Posts: 2,058
Wind Correction 1nm per 10kts ???
If your descent takes 20mins, that's a third of an hour.
Say a 60kt average wind component, for a third of an hour is a 20nm correction.
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What?!? No, you're making it too complicated which you can't do with RoTs. If my 3:1 gives me a ToD of 100nm and I see a TW of 50kts, I'm going to add an extra 5nm to my 100nm for a new ToD of 105nm.
Don't add a time function into this.
And say I need to slow from 300 to 250 for a restriction too, I would then add another 1nm per 10kts of slowing for a grand total ToD of 110nm.
Of course, while in the descent, you're always checking your 3:1 calc and fine tuning the descent as needed. Good RoT for a required descent rate is to add a zero to your GS and divide by two.
Ex:
400 kt GS
Add 0 to get 4000
Divide by 2 to get 2000 FPM.
KISS so it can be done quickly. You won't get perfect results but you'll be well within what you need to get the job done. Don't let the slop keep you up at night and don't try to figure out more accurate numbers because you undermine the entire reason for having a RoT.
Last edited by junebug172; 8th May 2013 at 19:32.