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ATC requests cloud tops at night

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ATC requests cloud tops at night

Old 16th Feb 2014, 14:30
  #21 (permalink)  
 
Join Date: Nov 2013
Location: United States
Posts: 175
Oh OH!!! I know the answer to this one....

How to calculate cloud tops with wx radar...

(But you will have to depressurize the airplane)

Remove the radar display unit from the panel (although you may need to sneak a screwdriver on board because pilots aren't allowed to have screwdrivers).

Toss the unit out the window and start the timer...

When your unit disappears into the cloud tops, stop the timer...

Use the terminal velocity formula, v = the square root of ((2*m*g)/(ρ*A*C))

The rest is pretty academic.

(This really works by the way but I had to quick Google that last part)
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Old 16th Feb 2014, 14:37
  #22 (permalink)  
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Yes, that would work, it is establishing 'C' that is the difficult bit.

That's probably how Nemrytter does it, I guess. Clever chap.
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Old 16th Feb 2014, 21:40
  #23 (permalink)  
 
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not if you are inverted....
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Old 18th Feb 2014, 20:48
  #24 (permalink)  
 
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That's probably how Nemrytter does it, I guess. Clever chap.
No, we just have more sophisticated processing than the standard cockpit display (even though the hardware is the same). Unless you are looking at a huge tropical convective cell then the returns are always very small and would be tricky to see on the tiny screen.

As someone said on the last page: It's "impractical." But it's not impossible.
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Old 2nd Mar 2014, 08:58
  #25 (permalink)  
 
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Originally Posted by zerozero View Post
ATC should have asked some poor turboprop pilot slugging it out in the high teens, low 20s.
Admit it, you're feeling nostalgic about those days, aren't you.
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Old 2nd Mar 2014, 10:28
  #26 (permalink)  
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There are always those who enjoy to confuse apples with bananas.

The thread subject is: "ATC requests cloud tops at night "
and not: ATC requests TO CALCULATE cloud tops at night.

All that ATC wants in this case is:
Pilot Visual report, using Pilot cockpit windows vs Pilot altimeters, during climb or descent. During level flight just say you are bellow,above or on top.
PS
If you can not make the difference between night-sky
(with or without moon, the darker the more stars should be there ! )
opposite to no-sky-visible due to in-cloud conditions then no calculation will help you.
 
Old 2nd Mar 2014, 13:08
  #27 (permalink)  
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Originally Posted by glendalegoon View Post
of all the statements so far, compressor stall has the answer.

you should have asked him. why didn't you?

isn't it possible that he was using the radar to make a quick search for buildups before giving the answer based upon climbout visual observation?
Actually, I did ask him. He was playing with the tilt and a few small green splotches appeared. He used a straight forward formula based on tilt and distance to green splotches(it has been a while now so I don't remember the details). I just thought that I would ask on here as well as I was a bit skeptical but not sure. Hope you don't mind me trying to get a second opinion.

It did not appear to be a night of any buildups. There was midlevel cloud below with very little but some light with no real depth perception. I will say that we were flying over an area where public TV had said would have rain on the ground.
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Old 3rd Mar 2014, 04:50
  #28 (permalink)  
 
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Originally Posted by A Squared
Admit it, you're feeling nostalgic about those days, aren't you.
Never did get rid of the nervous twitch in my eye.

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