Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Question About The Hemispherical Altitude Rule  
User currently offlineMir From United States of America, joined Jan 2004, 21637 posts, RR: 55
Posted (8 years 1 week 2 days 18 hours ago) and read 10634 times:

I've got a question that may sound pretty stupid, but what the heck:

I know that when heading between north and south via east, you fly at odd thousands, and that when heading between south and north via west, you fly at even thousands (in the US and not above FL410).

What happens when you start off heading southwest, but over the course of your route you start heading southeast? Do you have to either climb or descend 1,000 feet? Or does it not really matter?

-Mir


7 billion, one nation, imagination...it's a beautiful day
3 replies: All unread, jump to last
 
User currently onlineTripleDelta From Croatia, joined Jul 2004, 1123 posts, RR: 6
Reply 1, posted (8 years 1 week 2 days 17 hours ago) and read 10624 times:
AIRLINERS.NET CREW
PHOTO SCREENER

Quoting Mir (Thread starter):
What happens when you start off heading southwest, but over the course of your route you start heading southeast? Do you have to either climb or descend 1,000 feet?

Yes, the a/c has to climb or descend. Otherwise it'll pose a threat to other traffic on the same level, but coming from the opposite direction, possibly leading to some nasty head-to-head situations.

However, operationally, this depends on a lot of factors, traffic included. For separation and safety reasons you can have an a/c remain on its level until sufficient separation between other traffic has been achieved (given that there's no "threatening" traffic on that level), with a level change afterward.

[Edited 2006-09-14 08:57:56]


No plane, no gain.
User currently offline3DPlanes From United States of America, joined Apr 2006, 167 posts, RR: 0
Reply 2, posted (8 years 1 week 1 day 21 hours ago) and read 10527 times:

Just to elaborate, the hemisphere rule starts at 3000 feet. Below that is open (outside of controlled airspace).

IFR aircraft fly on the 1000s, VFR aircraft fly on the same 1000s + 500. And, the altitude is based on your -track- not your heading, to account for crosswinds leaving your nose pointed the wrong way for your altitude...

In real life, as suggested above, both IFR and VFR aircraft can be given altitudes that don't conform, assuming they are being controlled.

And, the altitude you use is for the major lengths of the routes. A diversion for traffic or weather (cloud clearance if you're VFR) won't necessitate an altitude change, assuming its short and you return to your original track..



"Simplicate and add lightness." - Ed Heinemann
User currently offlineDeltamike172 From United States of America, joined Mar 2001, 67 posts, RR: 0
Reply 3, posted (8 years 1 week 1 day 21 hours ago) and read 10521 times:

The official rule is 000-179 (i believe it is) you should file an eastbound odd alt. 180-359 you should file even. Now, when its a north south routing, it can be difficult to figure out which one works better. Occasionally, certain routes like this will have some sort of SOP that states that all aircraft on such a route should be at either odd or even all the time. Other times the altitudes are determined in relation to other traffic. Anything procedurally related will be relayed to the pilots when their altitude is amended, and air carriers quickly catch on to what to file the next time they fly that route.

And of course, the final solution is simply make sure traffic won't hit, using whatever rule you need to use.

There is plenty of traffic at the appropriate altitude for direction of flight that are in conflict with each other. If one plane is eastbound on a 090 heading at FL210, and another plane is eastbound on a 070 at FL210....they're gonna be in conflict eventually. Thats what ATC is for.

DM


Top Of Page
Forum Index

Reply To This Topic Question About The Hemispherical Altitude Rule
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Question About The Engines On The Bon Jovi 707 posted Tue Jan 24 2006 04:04:48 by Bohica
D.F.D.R. Question About The KLM/PANAM Crash posted Mon Jun 13 2005 20:45:40 by Iberiadc852
BAC 1-11 Vs. F28: Question About The Spey... posted Fri Sep 10 2004 22:15:26 by LVZXV
Question About The Fmcs In Boeing 767s posted Thu Apr 29 2004 10:01:34 by Garnetpalmetto
A Question About The Piper J3 Cub? posted Fri Feb 20 2004 01:09:46 by Mr Spaceman
A MX Question About The EMB-135/140/145. posted Wed Feb 4 2004 01:16:25 by Viflyer
A Question About The B2 posted Tue Jan 27 2004 22:07:48 by Radarbeam
CFM56 and a question about the ignition system posted Tue Jan 20 2004 02:56:47 by Diego
Question About The A380 Takeoff Performance posted Wed Dec 31 2003 00:37:00 by PVD757
A Question About The A320? posted Thu Sep 25 2003 01:25:28 by Mr Spaceman
Question About The PW4000-94 posted Sat Feb 7 2009 17:30:14 by Placekicker
Question About The First Day Of Ground School posted Tue Dec 9 2008 20:38:04 by Triebwerk
Question About The 737-100 Design posted Sat Jul 26 2008 03:11:07 by Columba
Question About The 24hrs Before Your Flight posted Sat Jan 19 2008 18:15:06 by FastEddie07
Question About The 727 Lights. posted Sun Mar 11 2007 03:55:20 by Beau222
Question About The Propeller Contrails posted Wed Feb 7 2007 18:05:28 by Ariis
Question About The Thrust Reverse posted Wed May 6 2009 20:10:24 by Vietsky
Question About The PW4000-94 posted Sat Feb 7 2009 17:30:14 by Placekicker
Question About The First Day Of Ground School posted Tue Dec 9 2008 20:38:04 by Triebwerk
Question About The 737-100 Design posted Sat Jul 26 2008 03:11:07 by Columba
Question About The 24hrs Before Your Flight posted Sat Jan 19 2008 18:15:06 by FastEddie07
Question About The 727 Lights. posted Sun Mar 11 2007 03:55:20 by Beau222
Question About The Propeller Contrails posted Wed Feb 7 2007 18:05:28 by Ariis

Sponsor Message:
Printer friendly format