PPRuNe Forums - View Single Post - Why is the TA set at 18000 ft in the USA?
Old 21st February 2010 | 03:11
  #10 (permalink)  
helen-damnation
 
Joined: Feb 2004
Posts: 752
Likes: 0
From: Hades.
Because when you are below FL180, you'll always be on a local QNH, thus ensuring no altimeter error with regard to terrain, MSA etc. (Not including temp correction).
helen-damnation is offline  
Reply