Radar Headings vs. Flight Planned Route
 

Can someone help me understand the behind the scenes processes that make Radar Headings so popular with London.

On a recent flight from EHRD (FL100) the various Continental Controllers all had me flying either the filed route or DCT. However, the moment I arrived in London I was on headings (which exactly matched my filed route).

Similarly a flight to Scotland and back, on the way up I was on headings issued every 40 miles or so that tracked about 3 miles East of my planned route (until TNT). Coming back down, I was cleared own nav via several waypoints, but the handover to London once again went, 'Say Heading ... Make that a Radar Heading' and once again tracked exactly over my planned route but on Radar Headings.


Given the radar headings and the dct links between the waypoints followed the same path over the ground, there must be some procedural advantage for London of having everyone on headings (but the same advantage doesn't seem to apply to Amsterdam).

On headings minimum lateral separation can be used, on own nav it can't be.

So you're on headings so that other traffic, also on headings, can be climbed/descended through your level at no less than 3nm lateral separation.

If you're at FL100 there will be a lot of other traffic in the TMA that needs to be climbed above you or descended below you.

Roffa
 

Is that a "local" rule or procedure or an ICAO standard? I'll be using ICAO regs. for the first time in my career very soon. In the US we can use 3 miles regardless of whether the aircraft is on a heading, on route, or "direct."

V361
 

I guess your system works else the FAA wouldn't approve it , but if you're using 3 miles separation & one guy, not on an assigned heading, deviates just slightly, say to avoid a bit of wx, have you not got a "deal" ? Or is the assumption that no one will deviate without asking first ?

What surprised me a little, and prompted the question, is that with one exception (traffic crossing 1000 ft below) there was no one visually or on the traffic system showing within 6-8 miles anywhere close to my altitude for the whole time I was on headings. (I don't have full TCAS, but generally would expect to detect large aircraft transponders quite well.) It was from this that I guessed there must be some procedural rule or mental advantage London Controllers have when putting someone on headings. It doesn't seem to happen anywhere else and certainly my US, Dutch and German experience is that getting a heading means you are consciously being vectored off ones flight path rather than just ensuring you remain on the flight path.

It's certainly not ICAO. We use it "out of common sense" when tfc will come pretty close, high speed & nearly opposite. But all the time ? Sounds like overkill...

Due to the congestion and complexity of the route structure in the London TMA, tactical positioning of traffic with the use of headings is absolutely essential for an expeditious traffic flow. If all aircraft were routinely left on their own navigation the TMA would grind to a halt.

You may not require a heading to be separated from conflicting traffic in the immediate vicinity, but tactical positioning early on can prevent numerous conflictions from happening 20, 30 or even 50 miles ahead.

If you were overflying the TMA at FL100, you can be assured that if left on your own navigation, the result would be a significant reduction in the expedition of pretty much all the other traffic.

Lots of aircraft; complex airspace/sector design; separation standards; presentation to next sector, etc.

Why don't you arrange a visit to Swanwick and have a look for yourself; you'll get the picture fairly quickly I would imagine...

Thank you for the suggestion. I will do so.

I can understand the logic for tactical positioning of traffic. I also routinely experience in any busy TMA (with no complaints or surprise - because I know that's what's needed to keep things flowing).

What surprised me was being 'tactically positioned' exactly on my flight planned route (which out of interest on the South Coast was KONAN DCT LYD R803 SFD (The headings kept me within about 1 NM of my original magenta line) and going North was tactically vectored about 2 miles east of DTY DCT SAPCO N57 (to about TIPIL where it was own nav POL)

More reasons then from the route you gave first:

KOK-KONAN-DVR is opposite direction to all the London TMA traffic departing via DVR so giving you a heading nudging you slightly south of track gives us the best amount of space to get the TMA traffic quickly through your level. The LCY traffic will be passing FL100 somewhere between DET and DVR as is the Stanstead & Luton departures. Next you cross N613 between SOVAT & SANDY, all LCY, Biggin Hill, Southend and Rochester traffic have to be FL80 by SANDY, if you are on your track in conflict with one of these arrivals, we cannot achieve FL80 by SANDY unless you are vectored slightly southwards. The next track you conflict with is again traffic into LCY etc inbound along G27 (HASTY-BEXIL-ROKOS-SANDY that have to be FL100 by HASTY. Being your level, you will be vectored off track to avoid this route. Next, as you approach SFD (or 10nm before it) you will have a steady stream of LGW arrivals crossing from right to left attempting FL70/80 around TIMBA, again, if you are on track, that is not achievable. Once you cross that track, then depending on the LGW runway direction, you could be in direct conflict with departures if they are on easterlies. If on westerlies, then you will be in conflict head on with LGW arrivals via GWC-HOLLY-WILLO which also need to descend through your level.

For all those conflictions, you need to be on a heading to ensure separation or to tactically position you so other aircraft can achieve agreed levels. As to why it, in your opinion, only happens in the London TMA, then I guess that we are just that busy that you have to be.

Excellent detailed explanation there 5mb, PPRuNe at its best! :ok:

And one would be more surprised by vectoring that would have taken you much further from your route - as this would have required lots of coordination, killing the entire idea. You get 2nm off, someone else 2nm off on the other side, et voila.

Agree with Spekesoftly. I bet Mr Flynn knew nothing about all that!

Thank you all for your replies. Some of which I knew, some of which I didn't. Probably most interestingly, I hadn't appreciated that London requires one to be on headings to achieve reduced separation.


Equally, I had expected by the time I was 4 miles off track of L9 on my way to LYD I was clear of everyone climbing out DVR KOK (equally, I had thought most of the traffic was FL150+ by the time they reach DVR).

Live and learn! And I will take up the various offers of a visit.


Thanks.

ETC
 

In a case where the pilot deviates without asking, should it result in less than standard separation, it would be a "pilot deviation," and not a controller error/airprox here in the US. It is certainly not unusual to put aircraft on headings when in close proximity. BTW does ICAO have a "degree divergence" rule where you can use less than 3 miles if aircraft are assigned diverging headings by ??? degrees? If so that may explain why London TMA puts so many aircraft on headings. It's only allowed in terminals in the US last I knew, but center/area has been trying to get it in areas where 3 miles separation is available.

V361
 

Thanks for the reply. Sorry, can't help with the ICAO query - I do Apc Rad in the UK. We can use 3nm separation but with quite a few restrictions e.g. both aircraft identified, intentions known, within certain range of radar head, & separation must be back to 5nm or more before transfer to the Centre. I suspect this it the same at most units.

Vector 361 - there's no such thing in the UK, can't speak for ICAO

In the London TMA 3 miles separation is subject to a host of other conditions - below FL245, a minimum distance from the radar head (depends on the radar source) , identified and talking to a co-located controller with a rapid means of co-ordination.

However approach controllers can use 2.5 nm on base leg and final within 20nm of touchdown and I understand that is ICAO too.

From your post it seems that it's common in the US to allow aircraft to be on their Own Nav 3nm from each other? Maybe we're overly cautious but it wouldn't happen here - at least one and usually both would be on headings if that close.

Here in Austria its completely up to the controller how to use the 3nm sep; outcome has to be 3nm or 1000ft, no matter how.

That doesn't mean everyone here is pushing his/hers adrenaline by letting 3.1nm happen with a/c almost opposite or sharply crossing, but it surely is handy at almost parallel SIDs which are still close to each other (must be bloody inconvenient to assign headings to a/c on parallel tracks, one overtaking the other with min sep of 4,5nm when staying on the sid).

What's the real advantage of headings vs planned route? Don't mistake me, I love headings and use them whenever things take a closer look.
One argument I heard often is wx-deviations. Well, I sure count on any a/c to report any deviation, as is required (flight planned route doesn't allow for any deviation without reporting, at least in my FIR; same with heading)
Below the line I should feel even better when letting 3.1nm happen on flight planned route, because that is what is tracked. A heading's track might change when descending/climbing because of different wind.

I think ICAO says 10 nm from touchdown.

I have to say i was allways puzzled about the use of radar headings within the UK. Our flights from stansted to glasgow, manchester or even belfast were quite often completely on radar vectors from shortly after take off until the ILS whereas domestic flights within germany or spain are usually done using directs or flight planned route until within the TMA of the destination where radar vectors are used for positioning onto the approach.

That said i allways felt safe that way as the ATCOs are obviously knew what they were doing, it just was a source of conversation on the flightdeck as it is unusual when compared with the rest of europe.

Denti

You mention that apart from in the TMA in Germany then headings are rarely used;
In your examples about flying from EGSS to EGCC, you basically remain in TMA airspace the whole flight. As soon as you leave the London TMA then you will be soon entering the Manchester TMA.

Flying EGSS to EGPF then you will be on headings coming out of TMA due to the complexity of traffic around you, then as you climb up through the Daventry sector then you will be on a heading against fellow London TMA deps and also against high level Manchester TMA inbounds that need to descend through your level, not to mention all the cruising traffic in the low 200 flight levels. Once cruising then you will probably be released from your heading to POL or MARGO. Then the ATCO needs to start thinking about positioning you in relation to other Scottish TMA inbounds, so will set you up on a heading for Scottish ATC, then before you know it you are in the Scottish TMA.

We don't put aircraft on a heading for the fun of it. Our little country has a lot of traffic taking off rom it, landing in it & overflying it. If you are on a heading then 99.9% of the time it will be for separation purposes.

separation again.
 

This 3 miles thingy is quite interesting but on the LAM3A arrivals LHR, the headings are mostly within1nm of NAV track. Does that really make a difference baring in mind that once a heading is issued, an Airbus managed descent has to be controlled in HDG/OPEN DESC..not a big deal but more of an irritation since one then has to focus more on the profile. Also. within the London TMA, what are the ATC heading and speed ACTUAL, realistic tollerances for the a/c you're controlling? BTW...still don't buy that QNH and type readback mallarcky at LHR!!!!:O

So I gather if you use radar headings for aircraft in close proximity in case they deviate, then you must also use 1500ft instead of 1000ft for aircraft that will pass overhead each other in case they bust their level a bit?

<<still don't buy that QNH and type readback mallarcky at LHR!>>

Why ever not? It surely happens at many other airfields and it's to do with SAFETY. It is obviously essential to have the correct QNH and the aircraft type information is required because airlines frequently switch aircraft types without telling ATC. If you were in an MD-80, or 737 or similar and ended up 2.5 nm behind an A340 or 747-400 you might then understand why it is done.

It matters not what people say on here, UK ATC will continue to function the way it always does. So far as my old brain recalls, there has not been a mid-air collision in UK controlled airspace since 1946, which is something we're jealously proud of.

Daisy120, if you are coming from Hong Kong then you will probably be kept on route or slightly north of it because of where you enter the CLN sector (REFSO), if you are on a heading then it will be so that we can either parallel other EGLL traffic against you from the south, descend traffic thats inbound to other places in the LTMA against you or get you through the overflights that are always there. The times of day that the Hong Kong flights arrive is busy with all the other far east arrivals at the same time as well as the early arrivals from less distant places. CLN (the westbound side) is only about 50nm wide at its widest point and narrows like a funnel with all the airways meeting at LAM. So you have to put aircraft on headings to achieve what you have to do, especially if there is a large mix of traffic.

Aircraft on their own nav may deviate to avoid weather without first informing the controller, whereas if they're on a radar heading they have to request first before changing. The whole point of radar headings is to ensure separation and safety.
We don't use 1500ft just in case they bust their level a bit, but it's not unusual for controllers to give a 2000ft separation buffer in the instructed level if an aircraft will be rapidly climbing/descending and the two aircraft are likely to pass overhead, especially when there are military fast jets involved.

There are no tolerances, you should fly them as accurately as possible and always remembering that if you're Mode S equipped you are downlinking what you are doing to ATC.

This is important because a small heading deviation may well lose lateral separation and, especially on final approach, not flying the requested speeds may at best result in you being broken off the approach or at worst a wake encounter at low level.

If for any reason you're unable to fly requested speeds/headings don't just surreptitiously try and do your own thing, say something and ATC will accommodate as that's what we're there for.

so.... just to get this straight at last: in the uk you do not have to ask first to deviate because of wx when own nav? creepy.
I can't check my documents right now, but anyway, it never happened to me that a pilot deviated before asking me if he may. And every pilot I asked stated that he/she had learned from the beginning to ask for a deviation before turning.

@ron83: its 2.5nm 18miles from touchdown here... and I can't remember having the authorities here daring something ICAO didn't cover, so 20nm maybe right (or 20nm from runway end, which would be around 18nm touchdown). anyway, would like to look it up, pity I'm at home :E

BS- absolute BS. UK AIP "track keeping" refers. This has been done to death on this forum before.

Experience proves otherwise.

I should clarify: the use of the word "may" is in the sense that aircraft might do it, not that they are authorised to.
Pilots should, and normally will, ask first before deviating to avoid weather, but like Scuzi says, experience is that they don't always.

Jackie: I understand that sometimes aircraft will wander, but to preemptively cater for pilot violations is another great example of dumbing things down instead of making aviation smarter.

If a pilot deviates without a clearance to do so NAIL HIM/HER! Why do you plan for preventable errors? Prevent them in the first place.

The message will get through if enough companies/pilots get nice letters from the CAA.

Domo,

Showa Cho.

Showa, that is my exact point I was making earlier in this thread. That is why in the UK so many aircraft are placed on radar headings, to prevent the planes wandering and thus ensure separation.

I will have to disagree here. It's called defensive controlling. And gives rise to much safer skies by identifying potential errors and setting up actions to prevent anything untoward happening before it does.

Some of the comments made in this thread I think serve to highlight why a greater effort should be made for pilots to visit operational centres in the U.K particularly those in a TMA environment so they can see just why the controlling in this country differs from our colleagues overseas.

I'm sorry that it comes across that some of the things we do are unnecessary, or add excessively to your workload, but its the quality of the training that we recieve in this country, coupled with the complexity of many sectors, which makes much of this work necessary.

quote: 'but its the quality of the training that we recieve in this country'

so not applying radar vectors when separating with 3nm is unprofessional?

quote:
Quote:
to preemptively cater for pilot violations is another great example of dumbing things down
I will have to disagree here. It's called defensive controlling. And gives rise to much safer skies by identifying potential errors and setting up actions to prevent anything untoward happening before it does.

Personally, I rely on pilots to stay on their route almost as much as to stay on their assigned altitude. Actually, more level busts happened to me than misnavigations. So what you call defensive controlling would in the first place call for 2000ft vertical sep.

I do not cater for pilot violations either. I control my traffic so that normal separation is assured, counting on pilots to do what I tell them. I do have a plan to prevent collisions when violations happen.

What potential errors do you mean? You really sit at your scope and control like any of your targets is likely to deviate or violate at the next possible moment?

<<I control my traffic so that normal separation is assured, counting on pilots to do what I tell them.>>

Which is precisely what the London controllers do!

I'm not quite sure how me emphasising why it is that we use so many headings in this country was ever me having a dig at the professionalism of other ATCO's in other countries.

I personally, and I imagine almost every other ATCO valid in the UK would not rely on pilots remaining on their own navigation when using 3nm separation.

The purpose of my reply was purely to highlight to pilots why it is that we use so many headings. Dont spin that round to suggest that I was being arrogant as to the quality of ATCO's in this country compared to others.

Surely the routes can be designed so that they are all laterally separated with built-in height requirements (I hesitate to use the word "restrictions" because this has negative connotations) and don't need the intervention of controllers. I appreciate that the London TMA is small but surely this is possible in this day and age, I mean we're only talking a mile or two. It would certainly increase the capacity handling ability of controllers if they were not constantly having to control the tracking of all aircraft under their control, which seems to be the case from previous posts.

I haven't worked the London TMA so am happy to be contradicted, but having worked the "Celtic Fringes" after a life of working in ATC overseas I am somewhat astounded at how far behind current control techniques and practices NATS is lagging. I feel that there is an in-bred, blinkered culture of "we're the best and the rest of the world can learn from us". Whereas the reality is that the rest of the world has moved on and NATS seems to have been left behind in an anachronistic bubble. If I mention RNP or PBN in the UK, I am normally met with blank stares, which astounds me.

Surely, the only way to increase en-route capacity is to not have controllers putting all aircraft on their frequency on headings. I mean, this is so labour-intensive and distracting from one of the other primary functions of controlling after safety which is expedition.

The current methods of controlling in the London TMA must have an in-built limit as to how much traffic this method of controlling can handle. How close are you to that limit? What are the plans when that limit is reached? Or do you just sit back and watch all the traffic overfly to Paris/Amsterdam/Frankfurt or re-route to avoid the "weak link" in the chain?

On the beach

<<Surely the routes can be designed so that they are all laterally separated with built-in height requirements (I hesitate to use the word "restrictions" because this has negative connotations) and don't need the intervention of controllers. I appreciate that the London TMA is small but surely this is possible in this day and age, I mean we're only talking a mile or two.>>

On the beach.. With respect, you do not seem to appreciate the workings of ATC in a TMA. "A mile or two" is a huge amount in busy airspace with inbound, outbound and overflying traffic with enormous speed variations. Radar is there precisely to expedite traffic yet you appear to be advocating a return almost to procedural control.

I know what RNP and PBN mean but flying particular routes with a hgh degree of accuracy does not solve the problem of many aircraft climbing and descending on crossing tracks; some form of control has to be imposed. Some of the earlier postings on this thread from DTY/LKS and others explain the problems very well.

I do very strongly urge you to visit Swanwick when you are next in the UK so that you can appreciate the problems they face. It might assist you with your consultancy work.

ok la.
 

DCB and 1985, thanks for the heads up. Definitely, a trip to Swanwick on the cards...is there a laid down protocol for the guys to organise a visit??(letter, e/mail etc). I fully understand that traffic density, especially with 'funnelleing' occurring close in, increases collision threat but surely if, eg LAM3A, all inbounds are mandated to fly the STAR, obey the SLP's etc, headings would be minimised....?
Now then, this QNH business, inclusive with the departure ATIS:if we are underlining QNH readback as a safety issue then why do we not include it with the confirmation of the arrival ATIS? For London, its simply a/c type. Outside UK, its a rarity to read back QNH until one has been cleared in the descent to an altitude; after all, one of the fundamentals, even at the basic stages in R/T education, was to keep the R/T broadcast, short, concise and clear. I do find that at LHR and particularly with London East, there can be so much R/T traffic on freq, that simply getting a word in, incurs quite a delay. By acknowledging, prior to start request, that you are.."callsign, stand, type and atis "X ray", you are confirming that ALL the essentials have been received. Afterall, if this is to recap the absolute safety issue of setting the correct QNH, then prevalent in other matters of safety to the a/c operation would be surface wind gust(to possible a/c limit across the runway and temp with dew point..Eng anti ice procedures etc...so why not read back the whole ATIS verbatim???...anyway, last on this one since I fear its becoming a polemic!!;)