"Procedural Tower"

[Martin Loxbo]

The term "Procedural Tower" is misleading since it implies a procedural (i.e. non-radar) control position, when the definition according to the policy includes radar services.

What the term actually describes is a combined position providing both aerodrome control (TWR) and approach control service (APP). We have many of these in Sweden at minor airports where a single controller is responsible for the TWR and APP service combined. Common to all of these is that they use radar (or other ATS surveillance means), so none are in fact procedural. When the GRP came into force we initially considered designating all these positions as APP positions, but that would have restricted all these minor airports to S3 and above, so we decided to stick with the TWR suffix (which also corresponds with the correct RT callsigns) while giving all students training to handle approach control at minor airports as part of their S2 training.

In Sweden (IRL) we don't have a specific term for these airports as it's the normal way for us to operate minor airports. I know in the UK they use the term "Radar In Tower" (RIT). In any case the term "procedural" should not be used to describe any position that uses radar control.

As a side note, real life terminology tends to move away from using the term "radar", as other surveillance systems (ADS-B, WAM) are coming into use. For example, in Europe the term "Minimum radar vectoring altitude" has been replaced by "ATC Surveillance Minimum Altitude". As we implement modern terminology on VATSIM it might be worthwhile to make this terminology "technology neutral" as well to avoid any confusion as different surveillance systems are being simulated.

[Mateusz Zymla]

It's not this case. If you have a single ATS unit, providing SSR services for bot CTR and TMA, then you'd need to design _APP for it, because S2 are not eligible to provide Approach Radar services, as it's part of the S3 training. Please, bear in mind that Approach control with surveillance service differs from TWR aerodrome surveillance control service within CTR (8.9, 8.10 DOC 4444), and you can teach and allow S2 to use ATS SSR within aerodrome control.

 

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while giving all students training to handle approach control at minor airports as part of their S2 training.

In this case, introduce given positions as APP and allow these people to train as Solo Approach Validated trainees for given airports, currently allowing S2 to control de facto an APP position seems like GRP inconsistency in my opinion.

Procedural Tower endorsement is for TWR (radio Callsign "TWR"), that provides procedural control for both CTR and TMA/CTA Airspace with separation described as per Chapter 5 ICAO DOC 4444, based on position reports (without "radar/surveillance"), not as per Chapter 8 of the given document. 

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For example, in Europe the term "Minimum radar vectoring altitude" has been replaced by "ATC Surveillance Minimum Altitude" 

In Poland, PANSA still uses MRVA and is not planning to change that, so not sure where did you take this generalisation from hovewer, many documents (EASA included) uses SMA, that is true. 

Edited July 28, 2021 at 10:01 AM by Mateusz Zymla

[Martin Loxbo]

Hi Mateusz,

Based on the real life ICAO regs I agree with you (for example in Sweden all controllers at such positions have an ADI as well as APS rating IRL). But the VATSIM policy is not that detailed and I believe the intent here is to be able to give a realistic service at such positions without having to train the controllers up to full S3 level. This is also how we have operated these positions for over ten years without incident.

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6.05(e)Procedural Tower Endorsement 6.05(e)(i) A Procedural Tower Endorsement allows an S2 rated controller to provide limited radar and non-radar services where required by divisional or sub-divisional policy.

Regarding MRVA, sorry for the generalisation, but my point was to avoid using the term "radar" in our terminology where "surveillance" would be more appropriate. There are other sections of the GCAP that uses "surveillance" and "non-surveillance" which would be more appropriate terms.

(Perhaps in Poland all units have radar as opposed to other surveillance systems so there is no need to change the terminology? Anyway, that's beside the point.)

[Mateusz Zymla]

2 minutes ago, Martin Loxbo said:

Based on the real life ICAO regs I agree with you (for example in Sweden all controllers at such positions have an ADI as well as APS rating IRL). But the VATSIM policy is not that detailed and I believe the intent here is to be able to give a realistic service at such positions without having to train the controllers up to full S3 level. This is also how we have operated these positions for over ten years without incident.

I understand your point, and I agree it's a valid one, I just say that "Procedural Tower" endorsement doesn't fit given example.

Out of curiosity, why you want to allow people to serve APP (as you mentioned, even IRL they have APS), "without having to train the controllers up to full S3 level"? They actually utilise S3 skillset, as far as I can understand. If you want to "limit" them, at least at beginning, why not utilising it by allowing them control this, in fact, minor (way less occupied?) airports via SAV, and then, let them get the rating, but utilising Restricted/Major/Events endorsements (to keep them away from busier airports/busier times)?

6 minutes ago, Martin Loxbo said:

Regarding MRVA, sorry for the generalisation, but my point was to avoid using the term "radar" in our terminology where "surveillance" would be more appropriate. There are other sections of the GCAP that uses "surveillance" and "non-surveillance" which would be more appropriate terms.

(Perhaps in Poland all units have radar as opposed to other surveillance systems so there is no need to change the terminology? Anyway, that's beside the point.)

I edited my previous message, but it still sounds aggressive enough, so I have to apologize, as I couldn't formulate it the way it doesn't sound like one 😄 . Surveillance-translated version of the word is broadly used, "radar" (PSR/MSSR) is just part of "surveillance techniques" and yes, even though stations are fully equipped with ADS data encoding, radars are primary use (that is why, there is not officially recognized ADS-B control service provided in "procedural" airspaces. Good example of our is Rzeszow (EPRZ), where it's procedural airport, even though you can easily see traffic even taxiing on services like FR24. I guess, ATC can see them via all of these, but officially not allowed to use it, even for time prediction).  

[Martin Loxbo]

I was just about to edit my message as well when I saw your reply, as I had a look in AIP Poland and they actually use ATC Surveillance Minimum Altitude. Let's not get too far into what can be seen on FR24 vs. what's an approved system used by ATC. But I can give you an example from Sweden: At Kiruna (ESNQ), it used to a be fully procedural airport as there is limited radar coverage in the area. ACC would hand over traffic with procedural separation descending to FL160 and Kiruna TWR would take over from there using procedural approach control (the MVA was FL100). A few years ago they installed Wide Area Multilateration (WAM).This basically uses the same technique as FR24, with ground based receivers triangulating the aircraft positions. It's actually so accurate that Kiruna TWR is allowed to use the WAM system for vectoring now. That's why we can't just call any surveillance based control "radar" anymore. 🙂 

4 minutes ago, Mateusz Zymla said:

Out of curiosity, why you want to allow people to serve APP (as you mentioned, even IRL they have APS), "without having to train the controllers up to full S3 level"? They actually utilise S3 skillset, as far as I can understand. If you want to "limit" them, at least at beginning, why not utilising it by allowing them control this, in fact, minor (way less occupied?) airports via SAV, and then, let them get the rating, but utilising Restricted/Major/Events endorsements (to keep them away from busier airports/busier times)?

I'm just reading up on the upcoming provisions in GCAP with restricted/major airspace etc, but the short answer to your question is that with the old GRP, we found that allowing S2 controllers to control these airports would be the best solution. Otherwise our smallest airports with very low traffic levels would be restricted to S3 and above. To restrict these positions to S3 would also have meant that the login callsigns would be APP with no TWR position available. For Kiruna for example, it would be ESNQ_APP even though the actual callsign is "Kiruna Tower". We also basically only have one TMA with enough traffic for S3 training, which is ESGG (ESSA is a major airport under GRP so initial S3/APP training has to be done elsewhere). All in all it would make things more complicated and confusing than simply training our S2s to be able to handle these airports.

[Mateusz Zymla]

2 hours ago, Martin Loxbo said:

I was just about to edit my message as well when I saw your reply, as I had a look in AIP Poland and they actually use ATC Surveillance Minimum Altitude. Let's not get too far into what can be seen on FR24 vs. what's an approved system used by ATC. But I can give you an example from Sweden: At Kiruna (ESNQ), it used to a be fully procedural airport as there is limited radar coverage in the area. ACC would hand over traffic with procedural separation descending to FL160 and Kiruna TWR would take over from there using procedural approach control (the MVA was FL100). A few years ago they installed Wide Area Multilateration (WAM).This basically uses the same technique as FR24, with ground based receivers triangulating the aircraft positions. It's actually so accurate that Kiruna TWR is allowed to use the WAM system for vectoring now. That's why we can't just call any surveillance based control "radar" anymore. 🙂 

I'm just reading up on the upcoming provisions in GCAP with restricted/major airspace etc, but the short answer to your question is that with the old GRP, we found that allowing S2 controllers to control these airports would be the best solution. Otherwise our smallest airports with very low traffic levels would be restricted to S3 and above. To restrict these positions to S3 would also have meant that the login callsigns would be APP with no TWR position available. For Kiruna for example, it would be ESNQ_APP even though the actual callsign is "Kiruna Tower". We also basically only have one TMA with enough traffic for S3 training, which is ESGG (ESSA is a major airport under GRP so initial S3/APP training has to be done elsewhere). All in all it would make things more complicated and confusing than simply training our S2s to be able to handle these airports.

1. Actually lol'ed and surprised, I'm pretty sure about a year ago it was still MVA for many airports (but i. e. 6.7.1-0 for GDANSK TMA says SMA since 2019...), seems like I didn't pay close attention to the chart details 😉 sorry bout that then! 

2. I know, but I guess that flying into WAM airspace requires you to own a transponder/mode S/ADS-B out? 

3. I know it would be limited to S3 then, but that's what I'm saying - "officially" it would be "S2 on solo train to S3". That's my suggestion, as your main motivation is based on traffic amount on given airports (and I get it), but definitions are already fitting to your case (as mentioned, would need to be _APP, I wouldn't look into radio Callsign vs. Login Callsign that much, we all love Bhremen Radar from DEP, APP all the way down to _CTR 😂). It might be difficult to find an exception rule for that (otherwise, there's significant risk, that we would go into S2 going into APP controlling without even training). 

[Martin Loxbo]

3 hours ago, Mateusz Zymla said:

3. I know it would be limited to S3 then, but that's what I'm saying - "officially" it would be "S2 on solo train to S3". That's my suggestion, as your main motivation is based on traffic amount on given airports (and I get it), but definitions are already fitting to your case (as mentioned, would need to be _APP, I wouldn't look into radio Callsign vs. Login Callsign that much, we all love Bhremen Radar from DEP, APP all the way down to _CTR 😂). It might be difficult to find an exception rule for that (otherwise, there's significant risk, that we would go into S2 going into APP controlling without even training). 

There are plenty of ways to go about this but I think we'll stick to what we've be doing for the last 10+ years. I think it's well covered by the "procedural tower" provisions in the GRP and upcoming GCAP. What I take issue with is the terminology of using the word procedural to describe a service that may be based on radar or other surveillance means, as this is confusing. It would be more appropriate to call it something like "combined TWR/APP position" or "TWR position which provides a limited approach control service".

It's worth noting that even IRL these units have restrictions on the amount of traffic they are allowed handle since there is only one controller (this could be along the lines of maximum 3 IFR movements simultaneously). So even if the real life ATC rating would be the same for a controller working a "proper" APP position compared to a combined TWR/APP, it doesn't mean that the combined TWR/APP works as a full blown APP unit. Considering this it doesn't make sense that a controller on VATSIM needs a "full blown" APP rating to control these positions.

 

3 hours ago, Mateusz Zymla said:

2. I know, but I guess that flying into WAM airspace requires you to own a transponder/mode S/ADS-B out?

Now we're getting way off topic... but anyway: Regarding WAM airspace, there's actually no requirement for mode S transponders (I had to double check but according to the AIP mode A/C is enough). I admit I'm not totally sure if the WAM stations interrogate transponders or if they just passively listen.

[David Zhong]

Something worth noting is that there appears to be many aerodrome control positions around the world that are authorised to use 3NM radar separation within their limited airspace where aircraft are beyond the range where visual separation is useful. Granted, that is not a "procedural tower" but just a "radar tower" with superpowers.

[Juan Amado]

Hi all,

I've read your comments and I find it very interesting.

Of course the main difference is about whether this endorsment is for "convetional control" positions (non-radar) or it is for "combined TWR/APP" positions.

It might be confusing as we in Spain have many cases. For example, San Javier (LELC) has 2 positions, TWR and APP, but because they don't use any radar, APP should control by position reports and procedural controlling.

Another example, in Asturias they only have one position for both TWR and APP and they have any type of surveillance (they may be rich or just because security for the royal family that is "living" there). They have MLAT, WAM, S-mode radar, SMR.

Another would be Granada (LEGR). Only one position but he uses no radar.

 

In conclussion, it must be defined as one of the 2 examples hereabove this endorsment.

[Juan Amado]

Morover I see it's important this endorsement.

Case it is combination of TWR and APP:

- S2 must know how to control also APP and it may serve as an introduction for the S3 APP.

 

Case it is procedural control:

- S3 must know how to control by position reports.

- In the case it is procedural and there is a TWR position utilized as APP (combined), I would forbid this position to all S2 (they can only connect as GND or lower). S3 can control if they have that endorsement.

 

Edited August 19, 2021 at 09:15 AM by Juan Amado