Why is FL180 the fixed TL in the US?

CaptLeslie

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Why is the transition level fixed at 18,000 feet in the US?
This is not the case in most other countries. Europe is considering having a fixed level. Some have suggested 10.000' while others say – lets do the same as the US.
Is there anyone who knows why we decided to select exactly 18.000 feet in the US (and not another fixed number)?
 

Bjammin

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I think FL 180 will give terrign clearance over the abosolute highest elevation in the continental US under very low atmospheric pressure.
 

CaptLeslie

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:) Thanks - just the kind of answer I was looking for!!
Any others?
 

clippyrip

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I fly in Alaska and 10,000 feet would not cut it. I'd smack into some very hard clouds (cumulo-granite ) if it were at 10,000 feet.
 

AV1ATRX

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Bjammin is right. It's based on terrain. That's why in Europe it's lower. In the Netherlands is 3000 feet, for example (IIRC). They just don't have mountains the size of the Rockies there.
 

GuppyWN

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Maybe the question should be "why isn't everyone elses TL 180?"

Gup
 

SVA_402

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Why would you question such a thing!? That's like going to church for 10 years and then saying wait, so why do we believe in this?
 

LR25

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Why do other countries us Meters?

QFE?

QNH?

etc.

I was told by some old timers that Eastern back in the day used QFE, any truth to that?
 

PeanuckleCRJ

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AA used QFE up until a few years ago.
 

Donsa320

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Why do other countries us Meters?

QFE?

QNH?

etc.

I was told by some old timers that Eastern back in the day used QFE, any truth to that?
'Tis true, and AA did too, among a few others. Only the advent of glass cockpits sort of put an end to that. I guess the programmers told them to shove it! <grin>
 

waka

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Maybe the question should be "why isn't everyone elses TL 180?"

Gup
Maybe when we get enough smarts to go metric, then they'll consider it.
 

waka

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Why would you question such a thing!? That's like going to church for 10 years and then saying wait, so why do we believe in this?
Funny you say that. That is exactly what happened to me. I should have stopped believing in that god stuff back about when I stopped believing in the Tooth Fairy and Santa Claus. Now I sleep in on Sunday mornings! :cool:

oops, thread drift......carry on
 

Dumb Pilot

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Terrain clearance at the low atmospheric pressure is the correct answer for countries to determine transition levels within their air spaces. In Japan for example, it is 14,000/ FL140 due to clearance with Mt. Fuji. In the eastern Caribbean in Guadeloupe's air space it is 8,000/FL080 if I remember correctly


Maybe the question should be "why isn't everyone elses TL 180?"

Gup
Perhaps the world doesn't really revolve around SWA after all

Why do other countries us Meters?

QFE?

QNH?

etc.

I was told by some old timers that Eastern back in the day used QFE, any truth to that?
Perhaps because other countries came to the conclusion that a measuring system based on the dimension of the limbs of a dead monarch was a silly Idea, I tend to agree.

QFE is still used in some areas, Dalian China is an example
 

legalalien

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China and a few of the old USSR countries still use Meters. Its a pain in the *ss especially when you fly an old steam gauge aircraft and they give you approach altitudes in QFE meters!
 

SFR

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Why is the transition level fixed at 18,000 feet in the US?
This is not the case in most other countries. Europe is considering having a fixed level. Some have suggested 10.000' while others say – lets do the same as the US.
Is there anyone who knows why we decided to select exactly 18.000 feet in the US (and not another fixed number)?

Because we in America invented aviation and we can make the rules!!!
 

crj567

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Maybe the question should be "why isn't everyone elses TL 180?"

Gup
Because they are weak and stupid.....Soon the wild dingos will eat them all.....
 

dalad

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Maybe the question should be "why isn't everyone elses TL 180?"

Gup
You're an idiot. period. I can't believe you were stupid enough to hit the post button. get out of your LUV world and see the world dumb a**.
 
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