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PACOTS vs NAT

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I have noticed when airlines fly the over the North Atlantic, they fly a standard Mach # like  M.810.  Once out of OTS go back to Econ on the Speed.  Do the airlines also do this for the Pacific flights, or do they just use the Flight plan Cost index all the way across the ocean?  

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The Pacific traffic is much less dense according to what I've read, and airspeeds are not as important as arriving at next fix at or near your estimates.

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I have noticed when airlines fly the over the North Atlantic, they fly a standard Mach # like  M.810.  Once out of OTS go back to Econ on the Speed.  Do the airlines also do this for the Pacific flights, or do they just use the Flight plan Cost index all the way across the ocean?  

 

Like Dan said, in the Pacific, it isn't as much of an issue of separation and spacing as much as it's an issue of making sure you hit your times. Hitting your times is actually a huge issue. I spent about a year working automation to take in and analyze reports sent over by Oakland Center of all the timing errors out over the Pacific. While I was doing that, I saw quite a number of reports coming in of people missing their times. There were plenty over the NATs too, for various other reasons (less timing and much more ADS-C and CPDLC issues), but Oakland took the cake for timing.

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That's interesting. Is the same true for AUSOTS?

 

Those may be a little more organized and rigid, but we didn't actually interact with them too much, so I can't comment on them with any specificity.

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I was under the impression radar coverage is better in the Pacific, due to the numerous American bases on islands and in Alaska compared to the North Atlantic that has no coverage. - David Lee

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I was under the impression radar coverage is better in the Pacific, due to the numerous American bases on islands and in Alaska compared to the North Atlantic that has no coverage. - David Lee

Not at all, the US has pretty much closed or mothballed all those places that were headlined in WWII..., even Midway is closed except for ETOPS emergencies.  Even if all those places had ASR radar, the radar is limited to line of sight or about 200 nm at flight levels and the Pacific is huge compared to that scale.

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Those may be a little more organized and rigid, but we didn't actually interact with them too much, so I can't comment on them with any specificity.

 

I already searched for AUSOTS and PACOTS superficially in google, but I didn't find very much. It seems that simmers don't love them as they love NATS...

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On the nats you have to keep a constant speed to regulate the traffic, much to vatsim's bewildered oceanic procedure there is no magic hf/vhf radio bobbing around at 30 West on an imaginary island.

 

If you could free speed it and jump from track to track you end up piling into the back of someone going slower than you.

 

Like I said in the real world you can be half way across-the-pond at 30 West shouting into your hf radio as much as you want and the transmitter at Shannon, Kef, nassurak, St John's Wont hear you your out of range. don't be dupped by vatsims reporting rubbish every 10 degree East or west

I already searched for AUSOTS and PACOTS superficially in google, but I didn't find very much. It seems that simmers don't love them as they love NATS...

I'd say 90 percent of simmers dont understand Nat tracks. Have a look on vatsim now You'll see people on the z tracks in the afternoons, and the a tracks at night, and they'll be using 6 months old tracks anyways

I was under the impression radar coverage is better in the Pacific, due to the numerous American bases on islands and in Alaska compared to the North Atlantic that has no coverage. - David Lee

This guy gets it...

 

The only hf towers are In Kef,einn,cyyt,cyqx,cyyr,bgbw, lpla, lest for example thats why the coverage is crap. The Pacific youve loads of small islands with hf or vhf transmission

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I was under the impression radar coverage is better in the Pacific, due to the numerous American bases on islands and in Alaska compared to the North Atlantic that has no coverage. - David Lee

 

Nope - it's completely procedural (non-radar), with the exception of non-Oakland Oceanic airspace (Honolulu, and very small radii around the outlying islands).

 

 

 

Like I said in the real world you can be half way across-the-pond at 30 West shouting into your hf radio as much as you want and the transmitter at Shannon, Kef, nassurak, St John's Wont hear you your out of range. don't be dupped by vatsims reporting rubbish every 10 degree East or west

 

Most of it is ADS-C and CPLDC now anyway, really. I never got too many reports of not being able to raise anyone on HF when I maintained the Oceanic Errors/Reports database, beyond that.

 

 

 

This guy gets it...

 

Nope. It's actually MUCH, much worse. The entirety of Oakland Oceanic is procedural (non-radar).

 

Additionally, he was referring to radar. You're referring to HF. Radar is for aircraft observation. HF is for communication. Also, for the record, you can hail someone in the UK from the East Coast of the United states via HF if the conditions are right.

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The only hf towers are In Kef,einn,cyyt,cyqx,cyyr,bgbw, lpla, lest for example thats why the coverage is crap. The Pacific youve loads of small islands with hf or vhf transmission

 

I think you might want to look at an atlas.

 

The Pacific is orders of magnitude larger than the North Atlantic; though on a global scale it does indeed look as though there are lots of small islands, there certainly aren't many HF towers on them and there is a heck of a lot of empty space in between most of them, especially in the north and south-east. In many cases far more than anywhere on the Atlantic which is barely a puddle in comparison.

 

LAX-HNL is some 2,600NM with bugger all in between, compared to a 'mere' 1900NM or so SNN-YQX with the great circle route passing within a few hundred miles of Iceland and Greenland, and when you get to HNL there ain't much more on the other side -- over 1,300NM to Midway and over 2,300NM to Wake Island. Kyle would know more about Pacific routes than I, but make no mistake -- it is huge and most of those islands are incredibly isolated, some of the more isolated places on Earth outside Antarctica.

much to vatsim's bewildered oceanic procedure there is no magic hf/vhf radio bobbing around at 30 West on an imaginary island.

 

I get the sense from your ramble about VATSIM that your main gripe is that you would really rather go to sleep or otherwise not be encumbered with the "inconvenience" of making a position report once every 45 minutes or so.

 

VHF is line of sight and you are quite right that beyond around 200NM from a ground station you will not get any joy, but HF is not and is quite capable of being used over the distances involved as the longer wavelengths reflect off the ionosphere and thus can be received well beyond the horizon. HF is more susceptible to interference but in most cases (especially at night) still does the job and has done for many years. Nowadays, the vast majority of flights are using CPDLC/SATCOM etc which cuts down the voice traffic a bit, but I don't think the boys at Ballygireen are going out of business any time soon. Either way, the position reports are still being made.

 

Communications over the Atlantic are not really the problem. The issue is the lack of radar coverage, which is also line of sight and therefore non-existent beyond a couple of hundred miles. Hence why the position reports and accurate speed keeping, navigation checks etc are so important.

 

VATSIM has to use VHF frequencies because there is no HF architecture within FS -- if there was I'm sure there would be HF frequencies used. However, the simulation is of the HF procedures, which are entirely accurate.

 

Edit to add: I was curious, so I did some Googling around the Oakland ARINC HF network. You may be interested to know (I certainly was) that a mere 5 HF radio sites cover the entire Oakland Oceanic FIR: Barrow, Alaska; Guam; Molokai, Hawaii; Dixon, California; and Hat Yai, Thailand.

 

Not exactly "loads of small islands with V/HF transmission".

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One of my favorite things about the Atlantic airspace, is how well documented it is.

Here's a great video that is a good starting point to understanding it (Real world)

Many years ago, I remember going to a "Very early morning" event where an HF radio receiver was set up by an enthusiast, and we listened to Brisbane and Nandi FSS on HF from a location in the far west of Sydney with a massive antenna. There were moments prior to sunrise where we were also picking up aircraft transmitting to Oakland (San Fransisco Radio HF).

This is possible due to ducting, and the way HF works. (It's also the reason that HF carries so much interference in the audio).

https://en.wikipedia.org/wiki/Atmospheric_duct

 

 

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My first assignment as a new lieutenant (after 18 mos of technical training after getting a BSEE) was in HF radio in Europe for USAF, and my favorite sites were the aeronautical stations operated by the AF for the Defense Communications Agency (DCA) at RAF Croughton UK, Lajes AB Azores and Incirlick AB Turkey.  In the 1970s, HF radio was the only way aircraft kept in touch with the ground and the DCA operated a global-wide system for the military and special agencies including Air Force One.  At the time, HF radio was also the only way to communicated between the Azores and either Europe or the US, every message and phone call was via HF.  The equipment was fascinating for a new engineer and included everything from 45,000 W transmitters at Lajes to very early Westinghouse 3000 W transmitters at Incirlik, and antenna "farms" that sometimes required hundreds of acres.  This was pretty heady stuff for an enthusiastic "radio mechanic."  The operators at these locations were very skilled and dedicated to their professions, it was not a job that you could learn to do a few days but required months of supervised on the job training.  The nature of HF made an operator into a magician of sorts who could divine where the layers were and the optimum place in the spectrum.

Satellites have replaced all that infrastructure over period of about a decade.  It's amazing how well the HF managed considering how much harder it was to operate than a satellite radio.

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I am obsessed with liveatc so I'll plug the EINN feed again that finally came back online, expanded to cover fully the VHF frequencies for shannon https://www.liveatc.net/search/?icao=einn

HF coverage does not cover shannon but you can find NY, Gander, and santa Maria. https://www.liveatc.net/search/?icao=hf

CYYT has only the one center frequency you have to get lucky to hear any high center traffic.

Listen in and you start learning the operations and terminology. Oh and don't forget to donate to that great service liveatc.net if you enjoy it! I do. -David Lee

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On ‎10‎/‎2‎/‎2016 at 2:15 PM, scandinavian13 said:

The entirety of Oakland Oceanic is procedural (non-radar).

 

Kyle,

Not sure it adds anything to your conversation, but the NOPAC and NATS operated pretty much the same.  

Everyone needs some quality time up on R220.  :smile:

blaustern

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