Off-route traffic?

[Jonjo Air]

Hello everyone,

I was just reading EG_ENR_2_1 when I came across something I don't quite understand.

Firstly, Here is my understanding of things (which could indeed be wrong) Aircraft in the London UIR Receive a Radar Control Service from whichever sector's airspace they are in and OAT Mil Traffic talk to London Mil, either LJAO or East - Once again depending on there position.

So, ENR_2_1 lists London FIR, lists all the civilian frequencies and then Lists London UIR, and states all the FIR frequencies are also in use for the UIR. It then also lists the Upper Airspace Control Area, with once again the same set of frequencies. It then also lists frequencies for off-route traffic. This is what I do not understand. For example, 126.075 is listed for Off-route traffic in the London UIR South of the UL975 and west of the UA34. Would traffic in this area not be talking to either Area Control or London Mil? And I also understand 126.075 to be a Sector frequency at Area Control.

My question is, what is Off-route traffic, and why does it have specific frequencies (which are already in use by sectors) listed for such large area's of airspace? Would traffic in this area not talk to the relevant Area Control Sector or London Mil?

You can find the Upper Airspace CTA on page 4 of the document.

Thanks,
Jonjo

[Rossoneri]

Off route: when an aircraft is not "flying along the alignment and within 5 NM of the centre-line of published parameters of an Upper ATS Route"

[5milesbaby]

Off Route is a status afforded to Civil control once the military boys and girls have all gone to bed. It means that we do not have to coordinate any traffic with the military that is above FL195 that is also more than 5nm from the centreline of an UAR, therefore we start giving out some better direct routings. It normally happens in the evenings and at weekends. Your description however for 126.075 is incorrect. It should read all traffic west of (U)N866 as that UAR is controlled by 129.425 H24.

[Jonjo Air]

Thanks for your replies.

5milesbaby, I may have this wrong, but when Off-route status is handed to Mil control, can you only give direct routings within 5nm of the UAR network? or does it have to be within 5nm of the filed UAR?

also, this frequency - 129.425, is this an Area Control sector or a frequency solely for Off-route traffic?

Thanks again,
Jonjo

[5milesbaby]

There are no different frequencies for off route traffic. The UK Area Control civil sectors have defined boundaries (not the edges of airways or UAR but actual designated boundaries with no free space inbetween. A bit like counties on a map, we have horizontal & vertical boundaries that always touch someone else's) so the only proviso is that when off route, you still keep your own aircraft within your own airspace OR you make a phonecall to another sector if you are going to "clip a bit". For popular night time routes (ie into Birmingham/East Midlands from the Cherbourg Peninsula) the shortcut given keeps the aircraft still within the confines of the sectors it would normally use if staying on route to save repetitive coordination.

Off route status ISN"T handed to the Mil. London Military decide when all their usual activity has finished and they then tell CIVIL that we can use off route procedures. The only exception to this is we now have a set of routes that come off the ocean that can be used between certain times providing direct routings across Irish and British airspace.

Any aircraft within 5nm of the centreline of an UAR is considered to be on route. As soon as you are more than 5nm from the centreline you are then off route. All aircraft that are more than 5nm off the centreline MUST be coordinated with London Military UNLESS they have afforded us off route status. With the amount of closely located UAR's in UK airspace, it is possible for an aircraft to be over 30nm from the centreline of the UAR it is filed to be flying on but can still be on route because it has always been within 5nm of any UAR centreline during the deviation/shortcut routing.

Having now read the document you refer to, I think its there just to aid any aircraft that has been given a direct routing and is flying outside of any UAR so cannot determine what sector they should be in contact with so at least have a London frequency to call on (its the one with the best coverage for the SW area from what I remember). This is published as quite often as aircraft near the FIR boundary from the south they lose contact with Brest control as their VHF coverage gets thin. This happens due to the way the French bandbox their sectors for night time working. An aircraft inbound to the UK from Spain that then call Brest can stay on the same frequency all the way to the UK. If the French controllers don't transfer the aircraft to another one of their own frequencies for use in the northern parts of France the aircraft may not receive the French transmissions as they get close to the UK. Fortunately most pilots then look in the books and attempt contact themselves, using the document you have read, or sometimes they just know what frequency they should be on.

Hope that is a much better explanation for you, post back if there is anything you don't understand

5mb

[The Fat Controller]

The attitude to off route and the MIL is somewhat different in the airspace controlled by Prestwick ACC.
We often leave the UAR structure and route direct, but it is then up to us to coordinate with MIL as necessary.
When we first took over the southern North Sea a few years ago, London Mil were VERY surprised at our attitude compared to LACC.

Edited for spelling, amazed I can do it pissed in Pattaya at 1 AM

[Jonjo Air]

Thanks 5mb, an Excellent Explanation!

Interesting comment TFC!

Thanks for both your replies,
Jonjo