NAT Exit USA side

[Tonic Please]

Hello,

I am casually studying NAT's to incorporate into my simulator sessions (home). I am able to read and input the day's NAT route into the FMC but I am interested in what routing you receive once you have reached the exit point in US airspace.

For example, a flight from London to Florida (region). Todays southern-most track is:

E DINIM 51/20 51/30 48/40 46/50 URTAK BANCS
EAST LVLS NIL
WEST LVLS 310 320 330 340 350 360 370 380 390

Great. So when leaving BANCS, there's still a long way to go till Florida. Where does this routing come from? I know your own airline's planning office deals with it, but my question still remains: How is routing planned on leaving the NAT into the US?

Thanks kindly,
TP

[MarkerInbound]

The FAA and NavCanada have established North American Routes. They are listed in the northeast volume of the FAA Airport Facilities Directory in the supplemental section. The formatting won't allow me to cut and paste. The NARs are normally two parts. There will be handful of routes from the end point of the NAT to another waypoint, most of them just direct. From BANCS it lists six or seven transitions including direct WHALE and direct BRADD. Then further in the listing are routes from these fixes to major airports. A route is given from BRADD to KFLL and also KMCO.

[rab-k]

So when leaving BANCS, there's still a long way to go till Florida

Your London to Florida flight would most likely not follow the NAT OTS (North Atlantic Organised Track Structure) going into Canadian airspace, but instead fly a "Random" route to the south, e.g. exiting the London FIR into the Shannon FIR (SOTA) via GAPLI then for the Oceanic leg routing

OMOKO 48N015W 47N020W 45N030W 42N040W 38N050W 36N060W BALOO

After BALOO they would pick up one of the routes in the New York Oceanic WATRS area and follow that to destination; possibly JIMAC M327 SUMRS LOUIZ A699 etc into KMIA for example.

Flight planning via the OTS is not compulsory; the OTS just enables ATC to maximize airspace capacity in those areas of Oceanic airspace where the bulk of traffic wishes to route on any given day. These congested areas of traffic vary on a day to day basis according to the weather. Approx. 30%-40% of traffic will not flight plan via the OTS to cross the Atlantic, but will instead plan to follow what is termed a "Random" route.

For WATRS area see here West Atlantic Route System Route Restructure and Separation Reduction with the Chart.

[Tonic Please]

This is dead interesting - thanks muchly for the links. I shall read up on them today.

I'd like to bring your attention to the following website: FlightAware - Flight Tracker / Flight Status / Flight Tracking

Now do the following: To the right, one may enter a dept. and arr. city. Enter EGKK and KMCO. Then search. You will find live and old flights flying this route, mainly BA and VA (well, all in fact). Select one which has landed already recently, such as VIR15. Click the flight number. Now, you have a map route PLUS (of interest here), the actual routing, in this example: SAM L620 GIBSO UN514 DIDEL UL149 MERLY UL22 MOPAT TOBOR 5200N 02000W 5000N 03000W 4500N 04000W NATH DOVEY MANTA J55 DRIFT ZIZZI J174 ORF J121 CHS J79 BEENO J79 OMN CWRLD2

If we copy this text into this (exceptionally brilliant) website where it says 'Route': SimRoutes.com - Route Parser - followed by the departure and arrival airports (minus SID/STAR selection), we can then press Generate Route, wait a bit, scroll down and find a map of the route.

This real route was used by VIR15 a few hours ago. The entry/exit points can be found on NAT maps.

It goes without saying that I am not countering your comments, but could you explain why Virgin (and the same for other flights, I see) do indeed use an NAT, albeit a southern-most one.

Here is today's NATs for general interest.

https://pilotweb.nas.faa.gov/common/nat.html

One assumes that a 'Random route' is created by the dispatch office in accordance with oceanic control (both sides)?

MarkerInbound, I appreciate those comments. It's a shame I don't have access to the same information! But waypoints noted.

rab-k, how did you know what to post re. cordinates/waypoint names? Do you have a generator or you simply know them through experience?

Once again, thanks a lot. Links will be studied.

Best,
TP.

[wiggy]

It goes without saying that I am not countering your comments, but could you explain why Virgin (and the same for other flights, I see) do indeed use an NAT, albeit a southern-most one.

Because it just so happens that today the most southerly official track ties in with the routing that the individual company flight planners have calculated as the best London - Miami route. There often are one or two southerly tracks generated to facilitate the more southerly Stateside destinations but that's not always the case, hence the comment about random routing.

[rab-k]

45N040W NATH DOVEY

This particular NATH is a "stub track" where NY Oceanic identify a demand in their FIR which Shanwick Oceanic, (as the 'designers' of the Westbound OTS; Gander Oceanic designing the Eastbound), do not; therefore a half or "stub track" is designed from 40W purely to provide for the needs of NY Oceanic as identified by them.

DOVEY exits from NY Oceanic into the Atlantic High area of US airspace, and not Canadian airspace, which as I said previously is usually too far north for Florida destinations. (Not that they would never route into Canadian airspace, it is just that the weather usually means they are able to route farther south and closer to the 'Great Circle' route).

The weather determines everything in terms of routes in the NAT area. You are probably already aware that as the prevailing wind in the Northern Hemisphere is westerly, those flights coming eastbound will look to pick up a strong tailwind component, increasing their groundspeed, reducing flight times and saving fuel/€/$/£... Going westbound however, a reduced headwind component is required to avoid a significant fuel/time penalty, therefore those westbound flights will prefer to route via areas where the westerly wind is at its lightest.

Operators have sophisticated computer sustems such as Lufthansa's LIDO which calculate routes between destinations on a daily basis on the basis of forecast MET, ATC route charges, ATC flow control regulations, position of the NAT OTS, position of Jetstream, Great Circle, airspace closures due to military activity/industrial action, shortest flight time due to weather, most fuel economic based upon NM flown, etc. etc. A EDDF to KJFK route for example will therefore be different every day due to the variables involved in calculating the optimum route.

Oceanic "Random" routes, as with all other routes, are created by the operator's FPL department using systems such as LIDO, and are then submitted to ATC who, provided any regulation/rule applicable to a specific route has been met, accept that FPL. ATC doesn't get too involved in the production of a FPL except to identify to an operator if a particular rule or regulation associated with a route has not been adhered to. The operator will then simply resubmit the corrected FPL.

The reason I'm familiar with the routes is that as an Oceanic controller I see them at work every day...


edit:

Just checked out that website FlightAware > British Airways (BA) #253 Flight Tracker which reminded me of another factor - ETOPS.

[MarkerInbound]

Ah, but you do. The FAA has everything on line. Start at page 147 of the download.

http://aeronav.faa.gov/pdfs/ne_rear_05APR2012.pdf

[rab-k]

Further to MarkerInbounds link to the NARS, their European equivalent (NERS) are detailed here:

Eurocontrol

See page ENR 2-2-4-20 under 22 Procedures — Eastbound (North Atlantic European Routing System)