nwaf16dude
Well-known member
- Joined
- Nov 8, 2008
- Posts
- 305
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Coolest DC9 feature...the over the shoulder compass and mirror combination. The mirror comes in handy for checking out chicks
So, how do you figure out what rate of descent you need for a 3:1 or 2:1 ratio? I heard a rule of thumb of altitude*3 gives you how far out in nm to start down??
If I'm at FL330 and get cross TWINS at 110 and 250 you get this: (6 to 1)
330 - 290 = 4000 .. 4 * 6 = 24 miles. ; (3 to 1) 290 - 110 = 18000 ... 18 * 3 = 54 miles . ; 24 + 54 + 4 (for slow from 300 to 250) - 10 (for avg 50kt headwind for example) equals 72 .... So start descent 72 miles from twins.. (some guys may use 2 to 1 but I think 3 works better for the diamond elite HVC happiness)
Oh .. And do that every few thousand feet on the way down to check progress
Edit: oh and if you are in icing conditions or anticipate it, that changes things too
Thanks...Does icing increase or decrease the distance?
We don't have any actual ground-speed readout.
3:1 doesn't work on the -9. To hold pressurization while descending aboving FL290, you can't go to flt idle. Only flt idle below FL290, and then it's 2:1.
I thought the same thing when checking out on it, but 3:1 really doesn't work...on -9.
Used rule of 3's in the Lear. Amount of altitude to lose, drop the 0's, then multiplied by 3. 33000 to 11000, 22x3 = 66 miles from the fix at a 3000 fpm descent. Rinse and repeat a few times on the way down to verify combined with the TLAR method. Add in 7-10 miles if you have to slow to 250 at the end of the descent.
Would this work in the -9 as well? (thread got my curiosity)
If you've got a DME and a clock you just count how many 1/10's of a mile you fly in 36 seconds and add a zero!
Fly it like a -200 baby!
Gup