atc-discussion 'Spotlight' Series

[Harry Sugden]

Hello!

I'm going to use this thread to make the series of 'Spotlight' posts - that are being posted in the TG Enroute mentor and student area - public! The idea behind them is to focus in on a particular part of area controlling in a more detailed, but also hopefully more accessible, writing style. There has only been one so far, but I'm working on the next one to post in the private forum in the next couple of days, and at least one other mentor has said they might at some point... but if it ends up being a one man band, then so be it!

Disclaimer: Any errors or omissions are, unfortunately, my fault. Please let me know about them below.

Do drop me a message if you have any ideas for something you'd like focusing on, or if you might even want to contribute!

Jump to:

1. The BPK Area [South & Central] - this post
2. Turn and Burn, Baby Burn [North]
3. Tricky Crossings 1 - FRANE [South & Central]
4. Tricky Crossings 2 - TC SW [South]
5. Awkward Encounters 1 - Daventry Corridor [North & Central]

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(1) The BPK Area

I thought I'd hone in on a little area that requires a good deal of focus when controlling, and indeed explanation in training. This is relevant to South and Central students, and is the area around BPK. We see a criss-crossing of various bits of traffic here to the extent that it is worth understanding not just what you have to do with your traffic, but what's going on in your adjacent controller's heads too! 

Figure 1 - The Area in Question (from this post)



Gatwick LAM Departures (pink)

Let's start with these, but I recommend you read all of my carefully crafted prose to understand how all of this traffic interacts. These departures are transferred from Gatwick AIR to TC SE who - once finished with deconflicting them from BIG inbounds and other departing traffic - has to climb them up, up, up to FL130, ensuring that they reach FL130 by the TC N/S boundary. This is especially important if they are going to be able to climb above Essex inbounds, discussed later. If aircraft cannot reach this level, TC SE must coordinate with TC NE, who does not work this traffic even though it climbs through their airspace. In real life, these departures wouldn't (ordinarily) enter TC NE's airspace but on VATSIM, in order to simplify the airspace structure in this area, KK LAMs actually climb through TC NE's airspace for a little without being transferred over (see Figure 2, below). Positioned on a heading west of the DET-LAM track and climbing to reach FL130 by the boundary, TC SE transfers to AC Worthing.

AC Worthing in this area - i.e. when the a/c is overhead the London City CTR/CTA - owns the airspace from FL155 (the top of TC NE) up to FL215 (the base of AC Dover). The traffic is released for climb, and Worthing's job is to climb the aircraft to FL190 and position the aircraft to track east of HEMEL (the reason will become clear later). There is another condition here - the traffic must cross the northern edge of the London CTR at FL155 or above in order to leave TC NE's airspace by this point, else in this case, AC Worthing must coordinate with TC NE. Climb condition met, AC Worthing transfers these aircraft to AC Daventry.

Essex VATON-BPK inbounds (purple)

AC Dover hands Essex inbounds from their sector at FL200 by MAY, and AC Worthing then has the task of managing converging traffic over VATON. By default, this traffic must be on own navigation along the VATON-BPK track and 5NM minimum in trail - any deviations from this need to be coordinated with TC NE. AC Worthing shall also not descend aircraft below FL180 before OCK when TC South West is split, else the aircraft will descend out of Worthing's airspace.

In real life, these inbounds are descended to FL140 level by BPK, and then transferred from TC VATON (AC Worthing on VATSIM) to TC LOREL (TC NE on VATSIM). However, our agreement is different. This is because we have simplified the airspace structure in this area, as mentioned earlier. Because TC NE owns the airspace up to FL155 in the area beyond VATON, our agreement is descending FL160 from AC Worthing to TC NE. It is not a "level by" agreement - AC Worthing should transfer these aircraft as soon as is reasonably practicable following issuance of descent to FL160, as they will need further descent quickly from TC NE! Note that the aircraft must of course be 'clean' before transfer, especially from KK LAM departures which are also handled by AC Worthing, but not by TC NE.

Heathrow BPK/ULTIB departures (blue)

It is oh so tempting as TC NE on westerlies to have a BPK departure check in, see an empty BNN arrival stream, and say - "BAW428, London Control, climb now FL150".

But wait! In real life, your equivalent controller (TC NE Deps) wouldn't be able to do this, for until a good few miles after BPK, their airspace only goes up to FL115. Who's on top? The Essex inbounds! Remember the mention of a TC LOREL in real life? They handle the Essex inbounds descending FL140 by the Park, and will then descend them further to FL120 until further into their sector. Underneath sit the BPK departures, climbed to a maximum of FL110, and later FL150 before transfer to - on VATSIM - TC East.

If I've lost you at this point, then just remember this: Make sure to scan the Essex VATON-BPK inbound track for any arrivals before you climb BPK departures up to FL150. If you forget, you'll either have to stop the departure's climb later, or the Essex inbound will have to sit at FL160 (this will require coordination if it goes on for too long as the aircraft may enter TC East's airspace).

On Easterlies, there is another consideration. @Sebastian Rekdal is really the king of diagrams, so you can refer to Figure 3 (below) for this. In real life, there's this weird bit of airspace in this region that changes ownership based on the runway config, but we've got rid of this complication on VATSIM. All you need to remember is that, as TC NW, you should not climb ULTIB departures until they are within your sector (error in OP!) are only released for climb to a maximum of FL110 until passing west of the VATON-BPK track, subject to TC NE/EGLL traffic. Quite often you'll have LAM inbounds in the way anyway, but who knows when an Essex inbound will come trundling along that VATON-BPK track...

A quick return to the KK LAMs

This made sense in my head to come back to at the end. Remember that heading AC Worthing gave pointing east of HEMEL to KK LAM departures? This helps AC Daventry out with the job of keeping that climbing traffic away from Midlands (BB/NX) inbounds, who are handed to them by AC Dover descending to FL220 by HEMEL. AC Dover must also position these inbounds through the 'Midlands Radar Gate' (you can turn this on in Display Settings -> Stars -> Midlands Gate; and there is a diagram - albeit a little grainy - in the vMATS, section GEN 3.5.1.1). These inbounds can be on own navigation or on a heading, as long as they pass through the gate which is - conveniently - on the west side of HEMEL! The usual disclaimer applies - AC Daventry cannot turn an aircraft on a heading until they are within the confines of their sector. It is also worth noting that - without further coordination - KK LAMs are likely only able to be climbed to FL210, and the HEMELs no further descent at all when Worthing and Dover are split.

To Conclude

Even though I've made a lot of references to our smallest day-to-day TC splits, that doesn't mean that those bits aren't relevant. Knowing your massive VATSIM sector requires knowing the intricacies of its constituent parts. A lot of the above is relevant even if you are the whole of AC Central and AC South is online with no splits - or vice versa. You might have noticed that the original diagram also has the CPT direction Stansted departures (green) drawn on it - I didn't touch on these as I thought the BPK area was quite enough, but do have a think about how you'll get these up too!

Figure 2 - TC North East

Figure 3 - ULTIBs

Edited July 27 by Harry Sugden
Added index

[Lewis Corcoran]

How do you make these wonderful diagrams?

[Harry Sugden]

6 minutes ago, Lewis Corcoran said:

How do you make these wonderful diagrams?

I made the original one (Fig. 1) in Google Drawings, the same as most of the UK diagrams - I tend to leave the drawing to @Sebastian Rekdal now though since he loves it so much!

Edited April 13 by Harry Sugden

[Harry Sugden]

(2) Turn and Burn, Baby Burn

It’s week 2, and I seem to have found myself far out of my usual habitat, in the Manchester TMA. But in the current climate, I have had some time to do some digging. This post is most relevant to North controllers, old, new and upcoming - I had planned to talk about inbound releases and positioning of aircraft in the Daventry corridor too but the post was getting long enough, so I’ll save that for another time. 

Disclaimer: I cannot be held responsible for this technique causing a conflict, especially if you don’t read this from start to finish. ?

Turning and Burning!

It’s definitely one of the coolest named techniques out there – in the vMATS, we refer to it by the more mediocre title of ‘Vectoring Outbounds Subject Inbounds’. You may have looked at some of the SIDs from Manchester before and thought ‘how on earth do I climb these departures safely through the inbound stream?’ – well, this will hopefully explain how.

The way inbound and outbound procedures in the MAN TMA interact requires a significant amount of tactical intervention from controllers. Tactical intervention is the vectoring of aircraft off published procedures or planned routes, in order to manage conflicts that arise because of a particular traffic situation, or in the case of Manchester, conflicts that are basically inherent to the procedures. As part of the UK’s Future Airspace Strategy (airspace modernisation), airports and NATS are working to design new procedures that are less workload-intensive, making better use of modern technology. [Figure 1 comes from a presentation given as part of Step 1a of the relevant Airspace Change Proposal]

Figure 1 – interacting routes in the MAN TMA requiring tactical intervention. Dark blue – GP inbounds. Red – GP outbounds. Green – CC inbounds. Orange – CC outbounds.

But for now, I’m going to talk about a technique for handling some of this traffic - ‘turning and burning’ - which involves PC (MAN) controllers vectoring Manchester (northbound) departures off-route, in a tighter turn that loops back round toward the airport, climbing above inbounds, and then vectoring back toward their route.

There are some important general points to take note of:

• It is advised not to remove speed restrictions until aircraft are seen to have made the turn, in order to keep the radius of the turn to a minimum
• Think about how the wind might affect which heading you issue
• If you plan to climb the aircraft above the SID altitude, you must give the climb in the turn – causing the aircraft to level off will quickly erode the effectiveness of the tactical intervention

Previous advice on the forum suggests something along the lines of:

"DLH949, passing altitude 4000 feet*, turn right heading 085, climb now FL90".

(* due noise abatement)

The same advice stressed the need to give the “turn and climb in the same transmission unless you are very quiet”. If not, then “you have to climb the outbound as soon as they start turning onto the heading [as] we don't want them to level off at any point as they have to get above the inbound stream”. 

When are the techniques used?

(1)   When Manchester is vectoring inbounds from ROSUN for 05L/R vs. ASMIM and MONTY departures

For these, see Figure 2 for an illustration of the kind of turn the PC controller might give.

The Manchester vMATS details a number of conditions on the vectoring inbounds that help out here:

• Inbounds from ROSUN must be vectored on a track not less than the 215° track from ROSUN until they have intercepted the edge of the Low-Level Route – this includes for traffic vectored from the POL release point, which should be pointed at ROSUN initially, to then intercept this track
• MIRSI inbounds must be on a track of no less than 175° from MIRSI until south of sub-area B

But even with these conditions, previous advice suggests that coordination between PC (MAN) and Manchester APC is not uncommon.

Does it work for LISTO departures? The same advice suggests that the easiest option is to leave them at 5000’ until they have crossed the DAYNE inbound stream. However, if the traffic is light, then PC East may want to coordinate with Manchester APC to help climb departures through. Due consideration must be given to the fact that finding a heading which deconflicts from arrivals and provides the space to climb may be difficult. He who dares, wins... (I kid!)

Figure 2 – an illustration of a ‘turn and burn’ intervention when Manchester is operating on 05L/R.

 

(2)   When Manchester is vectoring inbounds from MIRSI for 23L/R vs. POL and SONEX departures

For these, see Figure 3 for an illustration of the kind of turn the PC controller might give. You must also note that:

• POL/SONEX traffic must not cross the runway 23L/R centreline below MSL+1
• Too tight a turn for an aircraft on a POL/SONEX SID could cause it to enter Manchester Approach South’s airspace and into conflict with the DAYNE hold – this must not occur without coordination

Again, the Manchester vMATS places conditions, requiring APC to vector inbounds from MIRSI on a track no greater than 090° until east of the MCT–ROSUN line, when traffic may then be turned right “if no conflict exists”.

Figure 3 – an illustration of a ‘turn and burn’ intervention when Manchester is operating on 23L/R. Note that the SONEX line crosses the centreline in this image – it must do so above MSL+1.

 

Some concluding comments

For both configurations, it is integral you understand the RMAs and how APC will typically vector inbounds. Whilst Manchester APC controllers are (supposed to be) aware of these procedures, the RMAs are ultimately established for the purpose of vectoring inbounds. Even if APC is following the rules in the vMATS, if it looks as if an inbound and an outbound might get too close for comfort, prior coordination must take place between you and Manchester to agree a plan of action. Don’t leave it too late!

Also think about the fact that some VATSIM pilots have a tendency to ignore speed restrictions – if you think they might, why not (re-)state the restriction? The more a pilot attempts to speed up, the lower the rate of climb you will get from them. You might have to make a proactive choice as to what you prioritise: is your frequency quiet enough to give the turn and climb separately, because you feel for this particular aircraft you might need to remind them to stay slow? Or do you jump straight on the phone and coordinate something?

But most importantly of all, the figures above are ILLUSTRATIONS! Only with practice will you come to learn what works, and do not always trust the book - or in this case, the forum post!

Only one question remains...

Will YOU turn and burn?

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[See also EGTT vMATS 2002 MPC 3.3.3.2.4, because my post is no substitute for the procedures. With thanks to Sebastian Rekdal for his help on the diagrams, and to Johan Grauers for some of the advice that feeds into this post. Plus, Adam Arkley and Arvid Hansson for reviewing].

Edited April 17 by Harry Sugden

[Harry Sugden]

(3) Tricky Crossings 1

It’s been a little while since my last post - apologies for that, but I’ve been having a really hard time coming to terms with the potential (luckily not full) loss of my beloved Squawk IDENT. I’m just really worried that I won’t be able to find all these aircraft that keep calling me up! Oh, and the small matter of some real world exams, for which revision must be supplemented with non-stop flying. Alas, there are more important things to worry about with crossing traffic.

This post is part 1 of at least 3 in a sub-series looking at ‘Tricky Crossings’. It might seem a very simple task for the number of words that follow, but if I flesh it out a little then perhaps for some, there’ll be one part of the wider explanation that makes the whole thing ‘click’. I’m going to be talking about crossing Gatwick FRANE departures across the LOGAN 1H stream…

IMPORTANT: Cross check the diagrams with the relevant sector diagrams for a more complete picture. Make sure to read the full captions to understand what they are trying to show.

Crossing 1 - FRANE

For these, you need to get your head around how we appreciate aircraft performance. Previously just that wishy washy criteria on your mentoring report that is an afterthought for you, and sometimes the mentor who has to think what to write in there. Not anymore! It really helps you to manage your traffic safely with a level of anticipation. Crossing FRANE traffic requires some setup first, however.

Part 1: TC South East

TC SE positions FRANE departures on a heading toward DAGGA climbing FL130 before transfer to TC NE. The positioning here is important. When holding is not taking place at LAM, it needs to be far west enough that it enables the crossing, as is about to be explained, but not so far west that it sits in the bit of TC NE that is only up to FL155. Otherwise, there is potential for conflict with Essex inbounds, Heathrow outbounds, and not to mention the inability of TC NE to climb to FL170, which is the next agreement to TC East (see Figure 1).

Even when you’re able to climb aircraft promptly, make sure to take the above into consideration. Here’s a little diagram that highlights where you should try not to put these planes.

Figure 1 - a comparison of the FRANE SID track (solid blue), examples of good positioning on a heading (dash-dot blue), and positioning that would prohibit TC NE from climbing the aircraft to FL170 on first contact (dash-dot red). It is advisable, even when the sectors are not split fully, to avoid positioning FRANE departures within the VATON box (shaded red).

 

Part 2: TC East

The most important thing for this crossing is that LOGAN 1H traffic must be given descent to FL160 level by SABER. Sometimes you’ll be told by mentors that you don’t have to use every intra-sector agreement when you are controlling a bandboxed sector, but there are certain agreements that really help in terms of crossings and traffic management. This is one of them. 

Unless the pilot has told you they cannot make the descent by SABER, or your eyes tell you that the pilot is lying that they will, then the aircraft being FL160 level by SABER means TC NE can appreciate the aircraft performance of FRANE departures, climbing them in time such that they route over the top of Heathrow inbounds!

 

Part 3: TC North East

Ideally, as soon as TC NE gets LOGAN 1H inbounds, they should give a further descent such that about halfway along the distance from SABER to LAM, you could reasonably expect the aircraft to have reached around FL130. (Obviously, you’ve got to use your eyes and your appreciation skills to work out whether this will happen.)

By appreciating aircraft performance, you then issue a climb to the Gatwick FRANE traffic, bearing in mind that at the crossing point (well, in advance of it!), you will need them to be at least one level higher than the inbounds to LAM. Given how early TC SE is usually able to climb to FL130 on VATSIM, the departures should be able to reach at least FL150 by the LOGAN 1H stream, most likely higher (see Figure 2).

 

Figure 2 - a comparison of the FRANE SID track (solid blue), and an example of a FRANE departure positioned on a heading (dash-dot blue) that has at least 15 miles to climb above FL130 (i.e. the agreement between TC SE and TC NE). The LOGAN 1H traffic is expected to be FL160 by SABER and with timely further descent, should be able to make at least FL135 by BRASO, enabling the crossing (solid burgundy).

Airspace Key:          * TC NE DB-FL175         ** TC NE DB-FL175; TC East FL175-FL245

 

Part 4: Summary for Central Controllers

Things to remember to make this work:

• The pilot needs to know as early as possible that they should expect FL160 lvl by SABER - use, for example, the phraseology “BAW43HA, expect FL160 level by SABER. When ready, descend FL250”
• Issuing the pilot with another descent instruction removes the previous level by instruction - thus, if you give someone FL160 level by SABER over LOGAN, and 5 miles later say “descend FL90”, the pilot has no obligation to meet the previous FL160 restriction
• That said, do not delay the descent beyond SABER. Get them handed off to TC NE in good time if split, and then get them down ASAP to ensure the crossing is safe
• Do not climb the Gatwick FRANEs into AC Dover’s airspace without coordination if they are online! Even when TC SE is not split from Dover, it is good practice to stick to the fully split climb restrictions, at least until you’ve worked out the technique and the airspace - that way, you’ll always know what to do when the splits are online

For all of this to work relies on two things: firstly, practice, in order to appreciate how it works in action; and second, monitoring, because committing to a crossing that is based on an appreciation of aircraft performance requires your ATTENTION. Don’t take your eye off the ball. Had I lost you?

If you can’t cross them over the top, the alternative is to think about whether you are able to ‘point behind’. In this case, you might point the FRANE departure at/just behind an aircraft in the LOGAN 1H stream, such that by the time the departure would reach the point that the arrival was at, they will be in excess of 3 miles apart laterally. Then as long as the next aircraft will reach FL160 level by SABER, climb accordingly. Take note that the distance from SABER to LAM isn’t far - FL160 to MSL in 31 miles is no easy feat with a delayed descent. So whatever you do, remember that you’ll have more problems by leaving an inbound high, than you will by keeping an outbound low!

[Harry Sugden]

(4) Tricky Crossings 2 - TC SW

And we’re back! Since the last post, we’ve had Dominic on his trip to the castle, SpaceX launched, rallies and marches abound, and COVID-19 hasn’t gone away. I’ve even completed my uni exams and am now trying to enter the world of work... wow, how things change, even if you don’t notice it.

But more immediately pressing is going to be rambling on about something Area Control-y in the hope that my take on it could give you some ideas. This time, it’s the turn of the TC South West sector for some interrogation. This is necessarily limited in scope - chuck in Farnborough traffic, Shoreham arrivals (yes, I had one during MWM), holding(!) etc., and everything changes. But I’m going to try to stick to the basics and let you do the rest. I’m going to talk about outbounds and inbounds, from and to Gatwick & Heathrow, during a westerly configuration.

Step 1 - Receive your perfectly streamed traffic from the south

Well, at least that’s the idea! I’m going to build up an image throughout each of these sections. By the end, it’ll probably look quite messy, but if you follow through and watch how things layer up, then I hope you’ll be able to see the job of TC SW emerge.

Here’s a Figure 1 to start us off, showing the TELTU and HAZEL inbound routes.

Gatwick

Two RNAV1 STARs merge at TELTU - the OTMET 1G and the VASUX 1G - and it’s the job of AC Worthing to present you a stream at this point with aircraft FL130 by TELTU. (The ABSAV 1G and GWC 1G STARs are for RNAV5 aircraft, so you shouldn’t get too many of these - but the same principles apply). 

FL130 is a little low on profile for these inbounds, so you have some time to play with before needing to give further descent if necessary. But if there is no holding, try not to delay this descent too much.

Another big tip for these is to think about the effect of routing direct HOLLY from south of TELTU, especially if the temptation is there as AC Worthing. I do it quite frequently, but it does mean that the track is more likely to route over BOGNA, with the potential to unnecessarily delay the climb of outbounds. Don’t be surprised if, when an outbound pops up, that you then have to intervene with headings. But this doesn’t mean that a cheeky direct HOLLY from the VASUX area is to be frowned upon!

Heathrow

Again, it’s the same principle. You’re fed traffic on the ROXOG 1H and OTMET 1H, descending FL130 level by HAZEL. This is a really useful and important level by to use on AC Worthing even in the absence of TC SW, as it ensures the traffic stays below the WILLO 3B inbounds to Gatwick, which we’ll come back to.

Don’t be surprised if a lot of these inbounds come to you on own navigation from AC Worthing, especially now that our separation requirements allow for traffic on HAZEL vs. TELTU arrivals to be as such.

Be very careful about giving vectors to Heathrow inbounds from the south - you risk narrowing the corridor you have for outbounds via SAM, the further west you go of the STAR track.

 

Step 2 - “BA9990 maintaining FL150, request further descent” - adding in the extra arrivals!

That was sounding too easy, so here it gets more fun. TC SW receives Gatwick inbounds on the WILLO 3B from AC Daventry, level FL150 by KIDLI. This traffic transits through TC NW’s airspace and it must do so without being turned and at FL150 unless otherwise coordinated. Do not - without coordination - turn or further descend this traffic until within TC SW’s airspace.

Here’s a Figure 2 where I’ve added in the WILLO 3B track.

However, even when this traffic is in your (TC SW) airspace, think twice about further descent. FL150 is very low on profile if the aircraft routes MID-HOLLY(-WILLO). It is 73 miles from KIDLI to HOLLY on the STAR!

1. The FL150 agreement helps you to merge the traffic with the TELTU inbounds, due the very fact that it is higher, and so doesn’t cause a natural conflict. As long as you leave them higher, you can use slight headings adjustments if necessary, apply some speeds, and present Gatwick with a level separated stream into HOLLY. 
2. Giving further descent may unnecessarily limit your ability to climb outbounds. 
3. But most crucially, I think, is that Heathrow inbounds are more important to get down!

Traffic on the BEDEK 1H arrival comes from AC West, to be level FL140 by BEDEK. On first contact, you can generally get away with a descent to FL110 due to the base of CAS, but again, it’s important to form your plan early in terms of level separating into OCK. 

Here’s a Figure 3 showing these BEDEK inbounds being kept beneath the KIDLI ones!

From HAZEL and BEDEK onwards, heading application for the purpose of streaming inbounds should generally be kept to a minimum. Speeds can still be useful for streaming, but remember that on first contact, APP may reduce them. With or without speeds, you must be level separating into a stack.

It is nice to give APP a stream, but it is not essential. It is, however, essential to transfer aircraft level separated and in such a way that they would be able to reduce to holding speed in time for the stack, if required. I think the streaming point is even more pertinent for Gatwick. They have a very sizeable RMA and on 26L can use the HOLLY-WILLO loop to their advantage to create miles as well. Don’t fret about the stream if you can’t make one!

 

Step 3 - Add in some departures - “Shawty got low low low low low low low low”

And here is where it gets fun! Here’s a Figure 4 showing NOVMA and BOGNA departures added into the mix.

Let’s start with BOGNAs who need to be presented to Worthing climbing FL170. Considering only traffic on the WILLO 3B, depending on where it is you may be able to give a sizeable climb on first contact considering the difference in speeds. This is yours to judge. However, think carefully about how they interact with TELTU traffic. Using headings can be useful to encourage this crossing, but you really don’t want to be using drastic south westerly headings when the aircraft is heading south/southeast. Bear in mind also, for all Gatwick and Heathrow inbounds, that APP can descend to MSL! So don’t bank on it being kept free if you transfer inbounds.

The picture for NOVMA departures is slightly more rosy. The crossing happens sooner, but bear in mind they are generally best kept below EGLL MAXIT-MID traffic. They also conveniently route underneath HAZEL, so a climb to FL120 (all other traffic considered) is a good start. Turning NOVMA deps and HAZEL arrs both slightly right can encourage the crossing to happen sooner, but consider whether turning NOVMA deps left is actually beneficial? Where will they end up? You are more likely to need to use headings to position all outbounds via SAM against each other. Climb NOVMAs to FL150 (there is no level by SAM requirement, as some have got confused about before), and give to AC Worthing.

With that, let’s focus on some Heathrow departures. Here’s a Figure 5 that adds them in.

 

Throwing in some GOGSIs, and you should keep them below the OCK inbounds, position them on headings vs. NOVMAs if necessary, climb to FL150, and give to AC Worthing. Simples.

CPT departures can generally be left on the SID unless there is more obscure Solent/Farnborough traffic; climb them to FL130, but be sure not to hand them off to AC West until they are clean of WILLO 3B traffic (see Example 1 in Seb’s post here).

MAXIT departures, again, keep them low, slight headings to encourage a crossing of the WILLO 3B stream, or to ‘point behind/between’ successive TELTU inbounds. Climb them to FL170, and ideally - along with BOGNA departures from Gatwick - position them according to their intention code 

West ----> East

SITET-ETRAT [E/E2/E3] -> XAMAB-VEULE [V6-1/X6-1] -> XIDIL-PETAX [P]

 

And finally, pesky Gatwick KENET direction departures, represented pictorially in this final Figure 6. 

In real life, these are restricted to one every 5 minutes because of the complexity, but we don’t get that much traffic on here to warrant that. The issue is that FL130 is very easy to achieve quickly. You must keep these departures under WILLO 3B traffic, positioning them sufficiently west of the KIDLI-MID track. You also need to slot them in between CPT departures from Heathrow, and need to make a decision as to whether they will route under or over BEDEK 1H traffic. Again, only transfer to AC West when clean, but rest assured that AC West will not aim to turn KENET outbounds into the BEDEK arrivals - with it being known traffic and all!

 

So, what’s my key message?

Put simply: Don’t be a pushover and give in to climb requests. Just get on with the crossover!

Or, in the words of Flo Rida, you gotta keep them “low low low low low low low low”.

 

Look how many words it took me to get through that traffic alone… your task, as a reader - be it a rated C1 or not - is to think about other situations TC SW might find themselves in. Some suggestions for things to think about:

1. What would you plan to do if an UMBUR 1S Solent arrivals came to you FL160 5 before OCK from AC Worthing? What does it need to get to next, and where would you put it?
2. Have a look at the STAR charts for the ELDAX 1S arrival for Solent, and the ELDAX 1V for Farnborough. What do you notice about the descent profile of the STAR? Is this traffic going to be under or over the departure and arrival routes I talked about above?
3. What changes if Gatwick is on easterlies, with Heathrow still on westerlies?
4. What happens if everywhere is on easterlies? Do you think it makes TC SW simpler, or more complex?

These questions might fall on deaf ears like the teacher asking a question to their new class. But I’d encourage some discussion, if you’re up for it?!

Edited June 27 by Harry Sugden

[Harry Sugden]

(5) Awkward Encounters 1 - Daventry Corridor

I’ve noticed that the type of people who don’t wear a mask on the tube also seem to be the ones who ignore the signs saying not to pass people on the escalator. You see, there is no guarantee - without a mask on - that the trajectory of the air you breathe is safely aimed away from the person on your right. You just cannot be sure there is adequate separation! See where I’m going with this?

Perhaps quite an obscure link. But in the Daventry corridor, if aircraft aren’t locked on headings, then there is little certainty as to their trajectory. So, let’s talk positioning!

Prerequisites

This post won’t cover how to stream inbounds on either the down side of the corridor (southbound) into/toward the LTMA, or on the up side of the corridor (northbound) into/toward the MTMA. But a key tip when working in the corridor is that paralleling inbounds to the same airfield (or eventual hold) does nothing but delay the inevitable. That is, that they will likely have to merge. There are some exceptions to this, such as if one aircraft is a lot faster/slower, so it can be worth having the room to play with. But it’s important that North controllers help Daventry out by streaming/positioning inbounds to the same airfield as best as possible.

Another prerequisite is a grounded understanding of the intention code system in the UK. You don’t necessarily need to know which exit point each intention code refers to, at least for the purposes of Daventry streaming. However, you do need to know the order of them. For example: E is west of V; H4 is west of H3; D4 is south of D2; R6 is east of U5, etc.

Here’s a map, as Figure 1:

Southbound

It is very much North’s job to do the initial positioning of southbound traffic, such that by the time they’re on Daventry’s frequency, it’s more of a final adjustment type role to make the stream look pretty down the corridor and enable descent. 

All LTMA inbounds from AC North are RFD upon transfer of communication to Daventry (see vMATS LAC 4.4.2), but even when PC is combined with North, stepping descent to FL290 and then later FL200 is advisable to ensure that once the aircraft has left AC North’s sector, they do not reenter. 

Generally, the inbounds are positioned west to east in the same way the airports are geographically located west to east. See Figure 2, and notice how Solent inbounds are west of Gatwick inbounds - the Solent fields are further west, and so is their routing via RISIN vs. KIDLI for Gatwick.

Figure 2 - Positioning of traffic in the Daventry Corridor

There are 6 groups of inbounds shown in Figure 2, but the width of the western half of the corridor (Sector 27) is at a maximum 37 NM, reducing down to 33 NM further south. Given you need to apply 5 NM separation above FL245 and keep aircraft at least 2.5 NM away from the western edge, at a push you may be able to have 6 aircraft abreast if they were exactly parallel with each other. However, considering the need to find a space for MTMA outbounds and overflights too, it’s worth noting that you may need to use speed control to help maintain 5NM if aircraft cannot be paralleled. 

PC East will leave most low level MTMA departures (mostly SHTs to EGLL) on their own navigation to HON climbing FL190. However, for anything departing EGCC and EGGP with an RFL of FL195+, PC East should be positioning these outbounds through the Honiley Radar Gate (see Figure 3). What this enables Daventry to do is to climb them up through the inbound stream, generally west of the busiest stream in that corridor, the BNN arrivals. Other traffic via Cx/AM/AS/Dx/EB may be positioned outside the gate without coordination.

Figure 3 - Honiley Radar Gate for positioning of EGCC/GP outbounds with RFL195+ via Worthing intention codes

All aircraft transferred on a heading from PC East are not released for turn. They are, however, released for climb, and with a climb of just one level to FL200, you can then turn them. In practice, I would suggest that you consider not descending LTMA inbounds to FL200 on first contact, if you can see MTMA departures that you will need to adjust the heading of in order to fit them into the (parallel) stream (and also because of the FL290 step I mentioned above). Remember that you should use vertical separation until the headings/positioning of aircraft enable you to erode this safely.

 

Northbound

As opposed to the southbound side, this side has just a few more conflicts inherent to the route structure. 

The first of these is the awkwardness of Gatwick LAM departures vs. Midlands inbounds via HEMEL (refer back to the BPK spotlight). Important things to consider:

• Gatwick LAM departures - these will be positioned east of HEMEL by AC Worthing and are released for right turns only if transferred on a radar heading. When Worthing and Dover are split, they are released for climb to FL210 only, due this traffic being unknown to Dover.
• Midlands inbounds - these will be positioned to track through the Midlands radar gate (see Figure 4) on a heading or own navigation, and when Worthing and Dover are split, they are not released for descent. In addition, this traffic cannot be descended below FL170 when TC NW is split from Daventry. (Ideally, BB inbounds will be west of those for NX). 

However, it is important not to delay the descent of Midlands inbounds any longer than necessary - they need to be down and underneath the LTMA departures ASAP!

Figure 4 - Midlands radar gate for positioning of Midlands inbounds by AC Dover

The second of the conflict regions is where Thames (excluding EGMC) inbounds cross the northbound flow routing west-east on the arrivals via ROGBI-TIXEX-ODVOD. Pilots plan to be FL200 by ROGBI on the JACKO 1H, otherwise FL220 level ODVOD. There’s not much more to say other than to use vertical separation and headings to cross them over.

The same logic that is applied to LTMA inbound positioning also applies to MTMA inbounds. The further west the airfield is, the further west they should be positioned. Both the KEGUN 2B (GP) and DAYNE 2A (CC) arrivals start at TNT, so help PC East out by positioning the GPs on the left!

For LTMA outbounds, the vMATS states that “TC NW shall endeavour to position these aircraft towards the east side of the DTY corridor” (LTC 3.2.2.2). This helps with keeping the MTMA inbounds - who need to reach FL200 by around the PC East boundary - on the left side of the corridor. Inbounds to certain airfields in the MTMA and nearby are RFD by AC Dover on transfer of communication to AC Daventry (for full details, see the vMATS, LAC 4.4.1). You may wish to use intermediate levels for this traffic such that LTMA outbounds don’t have to stop climb at FL190 until they are sufficiently crossed over.

The final consideration then is the positioning of LTMA departures (once they’ve been climbed) and overflights. Towards the northern end of the corridor, above the MTMA inbounds, you want to start fanning them out according to exits via BAGSO (Shannon), BEL (ScAC Rathlin), POL-RIBEL (ScAC Deancross), POL-NATEB (ScAC East). See Figures 1 & 2 for the intention codes and the pictorial representation of what you’ll need to get the hang of.

So, what are the key messages? 

1. North has a really important job in terms of initial positioning, setting up headings and levels such that EGLL inbounds from Shannon direction can cross EGKK inbounds from LAKEY, for example.
2. Use all the space you have when busy, but ensure you have a plan for if an MTMA departure takes you by surprise and you need to climb it.
3. Ignore airways, and use intention codes.

And most importantly, don’t let them wander around without a mask. Get them locked on headings!

Edited July 26 by Harry Sugden

[Henry Cleaver]

Nice post about a tricky bit of airspace, thanks Harry.