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Why is FL180 the fixed TL in the US?

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CaptLeslie

Member
Joined
Apr 15, 2003
Posts
21
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)?
 
I think FL 180 will give terrign clearance over the abosolute highest elevation in the continental US under very low atmospheric pressure.
 
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.
 
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.
 
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?
 
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?
 

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