Lateral Offsets (SLOP)
Thread Starter
Join Date: Jul 2014
Location: Las Vegas, Nevada
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Lateral Offsets (SLOP)
ICAO Doc 4444; §16.5.3
Almost everywhere in the world where SLOP is authorized, this seems to be the case where it is talked about in the respective AIP (or the Jeppesen Airway Manuals). Now, I know from experience that SLOP is permissible in the Pacific on the NOPAC and PACOTS routes, but I can’t find a single official source that states SLOP is permissible in Japanese oceanic airspace. Not in any Jeppesen document, not in the Japanese AIP…
Is there a circular I’m missing or something else I’m completely missing? Someone asked me how do you know where you can apply SLOP, and just giving a blanket statement of “non-radar, remote or oceanic airspace” isn’t always true. There has to be guidance and I’m not finding any. Any help?
Thanks
The routes or airspace where application of strategic lateral offsets is authorized, and the procedures to be followed by pilots, shall be promulgated in aeronautical information publications (AIPs).
Is there a circular I’m missing or something else I’m completely missing? Someone asked me how do you know where you can apply SLOP, and just giving a blanket statement of “non-radar, remote or oceanic airspace” isn’t always true. There has to be guidance and I’m not finding any. Any help?
Thanks
No help but just a comment; In the days before improved IRSs with GPS; aircraft were "scattered" either side of oceanic airways, owing to poorer navigational accuracy - resulting in random lateral offsets. It is the improved accuracy and reliability of laser ring gyro IRSs coupled with GPS that makes track keeping so much more accurate and therefore SLOP sometimes desirable.
If you unofficially applied SLOP of just 1 or 2 nm over the Ocean, who is going to either notice or care? (as long as you remember to cancel the SLOP after the crossing).
If you unofficially applied SLOP of just 1 or 2 nm over the Ocean, who is going to either notice or care? (as long as you remember to cancel the SLOP after the crossing).
Join Date: Nov 2017
Location: Finland
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
I found this from Japan's country RAR's in Lido:
3.94.7.3. Strategic Lateral Offset Procedure (SLOP)SLOP shall only be applied in the oceanic control area over the Pacific Ocean within the Fukuoka FIR.
3.94.7.3. Strategic Lateral Offset Procedure (SLOP)SLOP shall only be applied in the oceanic control area over the Pacific Ocean within the Fukuoka FIR.
No help but just a comment; In the days before improved IRSs with GPS; aircraft were "scattered" either side of oceanic airways, owing to poorer navigational accuracy - resulting in random lateral offsets. It is the improved accuracy and reliability of laser ring gyro IRSs coupled with GPS that makes track keeping so much more accurate and therefore SLOP sometimes desirable.
If you unofficially applied SLOP of just 1 or 2 nm over the Ocean, who is going to either notice or care? (as long as you remember to cancel the SLOP after the crossing).
If you unofficially applied SLOP of just 1 or 2 nm over the Ocean, who is going to either notice or care? (as long as you remember to cancel the SLOP after the crossing).
Regarding improved navigational accuracy - true. This has flowed through to non-surveillance ATC separation standards so that reduced tolerances can be applied to suitably equipped aircraft with commensurately qualified crew.
Once in Oceanic Control Area, slop away, up to 2 miles right.
Last edited by compressor stall; 7th Sep 2022 at 08:52. Reason: ref
But if you're in the middle of nowhere over the ocean - as I specified. That was my point.
Flying between NZAA-RKSI a small deviation ( less than one mile) around a developing CB near Noumea had Brisbane ATC send a CPDLC message, "Report back on track", Big brother is watching you!
Join Date: May 2000
Location: Seattle
Posts: 3,196
Likes: 0
Received 0 Likes
on
0 Posts
Likely because China often assigns a SLOP, so they accommodate incoming traffic from China. Once I had China assign me a 30 mi offset!
Along with a lot of other aircraft in the same middle. You can't just go rogue and help yourself to manoeuvring off your cleared route in Class A type airspace. That's consciously and deliberately taking away one of those layers of risk management for you and impacting all the others.
Think of it more as ATC doing their job and looking after you. If an off-route deviation developed into something serious (for whatever reason) and ATC did not query it, the subsequent investigation report would (quite rightly) castigate ATC for detecting something unusual and doing nothing about it. In the particular example you mention, the big brother was probably your own aircraft - it likely dobbed you in when it automatically downlinked the periodic ADS-C position report showing you off route, which in turn triggers an alert generated by the ATC equipment to the controller.
Thread Starter
Join Date: Jul 2014
Location: Las Vegas, Nevada
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Thread Starter
Join Date: Jul 2014
Location: Las Vegas, Nevada
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Point taken but I don't think flying in the congested airspace over Europe can be compared with crossing the GAFA on an airway 8 miles wide and no other aircraft with a thousand miles of you.