Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

SLOP in NAT HLA

Wikiposts
Search

Notices
Tech Log The very best in practical technical discussion on the web

SLOP in NAT HLA

Thread Tools
 
Search this Thread
 
Old 29th November 2021 | 04:39
  #1 (permalink)  
Thread Starter
 
Joined: Apr 2008
Posts: 247
Likes: 0
From: Test
SLOP in NAT HLA

Hi there,

I just want to get a clarification on this. I was reading Skybrary on SLOP and it mentions:

"f obstacle clearance considerations or other reasons apply, ANSPs are required to restrict the use of strategic lateral offsets. Lateral offset cannot be operated if parallel route centrelines are less than 30 nm apart."

As we know, NAT system has 1/2 degree NAT, which essentially is 25nm apart. If so, can SLOP still be practised in NAT HLA?

Thanks
extricate is offline  
Reply
Old 29th November 2021 | 04:58
  #2 (permalink)  
20 Anniversary
 
Joined: Dec 2005
Aviation Qualifications: ATPL
Posts: 4,999
Likes: 341
From: Hong Kong
Maybe read up on how a nautical mile is defined...
rudestuff is online now  
Reply
Old 29th November 2021 | 07:14
  #3 (permalink)  
Thread Starter
 
Joined: Apr 2008
Posts: 247
Likes: 0
From: Test
This brings me to another ques. understand 1deg = 60nm, But I have seen articles and notices of RlatSM being 23nm, 25nm and 30nm. I'm confused by this. Can someone care to explain?

"The RLAT Track will have half-degree latitude separation with the two tracks beside it. In other words, it will be spaced 30nm from the tracks to the north and south of it."

"
Reduced Lateral Separation Minimum (RLatSM) is the implementation of 25nm lateral separation standards in North Atlantic High Level Airspace (HLA) (Minimum Navigation Performance Airspace (MNPS)) for qualified aircraft flying within the Organised Track System (OTS)."

"
RLongSM (5 minutes longitudinal) and RLatSM (23 NM lateral on. ½ degree tracks in NAT Organized Track System"
extricate is offline  
Reply
Old 29th November 2021 | 08:39
  #4 (permalink)  
20 Anniversary
 
Joined: May 2005
Posts: 1,198
Likes: 32
From: France
1/2 degree latitude is only 30nm when the parallel tracks are aligned exactly east/west. Any other compass direction will reduce the lateral separation, as measured at right angles to the tracks in question. Somebody cleverer than me will provide a suitable formula, involving trig functions.
eckhard is offline  
Reply
Old 29th November 2021 | 09:19
  #5 (permalink)  
 
Joined: Jan 2018
Posts: 863
Likes: 0
From: Amantido
Ch of Long*Cos(Lat).
It's been a while since I've done GNAV and even that was a simplified version of the actual subject. So I stand to be corrected.
Banana Joe is offline  
Reply
Old 29th November 2021 | 15:00
  #6 (permalink)  
BBK
25 Anniversary
 
Joined: Feb 2001
Aviation Qualifications: ATPL
Posts: 501
Likes: 35
From: UK
It ain’t that simple

rudestuff

It’s not that simple as eckhard has explained. Perhaps you need to do the reading up? For the OP the SLOP can be 0, 1 or 2 nm right of track. Of course for weather deviations then left or right. Hope that helps.
BBK is offline  
Reply
Old 29th November 2021 | 16:42
  #7 (permalink)  
50 Countries Visited
15 Anniversary
 
Joined: Nov 2007
Aviation Qualifications: ATPL
Posts: 1,954
Likes: 30
From: Texas
A 2019 revision to NAT Doc 007 says you can offset in tenth of a mile increments if your aircraft is capable of doing so.
MarkerInbound is offline  
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.