ATC Question Thread

[ian00798]

If I hear pilots making CTAF calls on area, I generally let them know. It's generally a little embarrassing to the pilot, but I believe CTAF calls are safety critical.

 

 

[aplund]

Is there any coverage on LiveATC.net for Class G FIS?

 

 

[Garfly]

There is this one at Bathurst which combines a CTAF and two area frequencies.

 

 

 

[shags_j]

There are quite a few that are covered without you knowing. If you listen to the bathurst frequency, it includes 133.05 which is the frequency that I work on. Because we retransmit over a sectors frequencies that also includes 127.1 which goes from walgett to inverell, and 125.75 which goes to east of Armidale. Sometimes in slow periods it also includes the frequencies right up to ballina.

 

 

[Garfly]

Actually after I tracked down that particular LiveATC channel the other day in response to aplund's query I just happened to tune in for a listen. I heard a controller working hard to help a VFR pilot caught on top somewhere between Richmond and Bathurst. (I think). The ATC guy was enlisting the help of all kinds of other flights in the area; asking whether they could see any gaps where they were. Airliners got involved too. He was busy with it for a good 20 minutes. Turned out well in the end. Might have been you shags! ;-)

 

And yes, I was a bit surprised at how many sectors were being handled on that one frequency and what you've explained above clears that up.

 

One question I had: Do the controllers who oversee traffic in the Hunter Valley / Williamtown region (I mean on Area, such as 125.7) have access to primary radar returns on their screens? I'm thinking maybe on relay from Willy itself, which I presume would have that capability? That is, can they see nil transponder traffic and thus be in a position to warn of possible conflicts that involve primary paints? Though I suppose without accurate altitude information there's not much to be done even if they were visible.

 

 

[kaz3g]

[ATTACH=full]42112[/ATTACH] Interesting that the new ontrack guide suggests a radio call outbound but not inbound. I use words something like traffic eastern lane then as per that guide. If cloud base is low there may be opposite traffic at the same altitude so I like to keep to the right of the pretty purple dots and avoid nice round numbers on the altimeter - scary to see others as they pass close by.Personally I prefer the Glenburn gap if the weather is good enough.

If I'm going down to Essendon or want to join the InLand Route , I now fly a track close to the freeway rather than KIM. I then turn onto the Inland Route at Wandong with a call on Melb Radar frequency if relevant. The Glenburn Gap is a much shorter run to Moorabbin or the Yarra Valley for me and I have found it is often open when KIM is closed. It's narrow and I do a call to MR when iffy plus then a 10 NM call on the YV CTAF.

 

MR certainly know where you are and your altitude...he once asked me what my height was and I foolishly rounded it off a tad. He then told me to get my instrument checked!!!

 

Kaz

 

 

[ian00798]

One question I had: Do the controllers who oversee traffic in the Hunter Valley / Williamtown region (I mean on Area, such as 125.7) have access to primary radar returns on their screens? I'm thinking maybe on relay from Willy itself, which I presume would have that capability? That is, can they see nil transponder traffic and thus be in a position to warn of possible conflicts that involve primary paints? Though I suppose without accurate altitude information there's not much to be done even if they were visible.

I'm not sure, but I don't believe we get the Williamtown primary feed in the civil system. This may be because the equipment isn't compatible, we chose not to get the feed, or the feed is inhibited as it is meaningless to an area controller. I'm not actually aware of which is the correct reason.

 

I do see some of the primary returns from Sydney, but most aircraft also have SSR capability, and the difference I see on my screen at my display range between a secondary only return and secondary with primary is extremely subtle, and if I'm not looking for it I doubt I would notice it. Primary radar is really quite meaningless to an area controller, it's more a terminal tool.

 

 

[ian00798]

Having checked when I got to work today, we do indeed get the primary feed from Williamtown, however it really has no practical use for an area controller.

 

 

[Garfly]

Thanks, Ian. That's good to know. Could one practical outcome be that if the controller sees a primary paint getting close to a Romeo area, for example, that he/she might call up to warn the "VFR aircraft x-miles south of YYY you are approaching R123. Remain clear." for example? Or, let's say that Willy sees that an unknown primary paint has busted its airspace, would that controller ask Brisbane Centre to try to contact that aircraft (in the knowledge that Centre controllers can also see who it is they're talking about). Anyway, it's interesting to know that those of us without transponders are, at least near terminal areas, visible to controllers, albeit without, I guess, any useful altitude information.

 

 

[shags_j]

Keep in mind primary sometimes picks up boats and all manner of other stuff. But yeah definitely if a paint were getting close we would broadcast

 

 

[ian00798]

The problem with primary returns only is we get no level information. It may not be the case in the military system, it is definitely possible to get an estimated level by triangulating the angles from the return, however some ATC systems won't do that, because I suspect the chance of confusing it with a mode c level would be too high to get any meaningful benefit. I suspect the military air defence radars would give a height, however I don't know this for sure and I would also be surprised if their normal controllers could access this, that's more the role of the air combat officers.

 

In all honesty, if Williamtown get a primary only return in their airspace, we would provide any assistance Williamtown asked for, but I suspect you would most likely end up with a military aircraft doing some intercept "training" at your expense. I have heard of a case where a student busted airspace near Melbourne and upon having ATC try to contact him, did the good old turn of the transponder and ignore the radio trick. Unfortunately for him, they followed his primary return all the way to Moorabbin and then it was just a case of getting his callsign from the tower. If you bust airspace, you will definitely receive some kind of correspondence from casa. I believe in general it's a warning for a first offence. But if you doing something stupid like that pilot, you would be lucky if you ever got your licence back.

 

 

[Pearo]

What is the deal with VCA's? I know about them, but have no idea of the repercussions. Obviously, if I keep busting airspace, something is going to happen, but what is the normal procedure?

 

 

[ian00798]

I think it depends on your record, what caused the VCA, all sorts of things. In ink the penalties range from a warning from casa, retraining with an instructor/reeducation all the way up to suspensio/cancellation of licence, particularly if the VCA had serious safety consequences and was done in an intentional/reckless manner. I think the warning and may a sit down with an instructor to look through your planning processes would be the norm for a first offence.

 

 

[Garfly]

Violation scenarios aside, there are times when it's a comfort to feel un-invisible. In a given chunk of busy Class G airspace, I wonder, what, typically, is the proportion of aircraft with transponders to those without. I've often heard controllers taking pains to keep 1200 paints, and those with codes, aware of each other's proximity (above and beyond the call of duty, in a way). But wouldn't that effort be a bit hopeless if there were many more UFOs out there (legally) invisible to any watchful eye. I guess it comes down to the 'big sky theory' of separation; which holds pretty well for a lot of this country but, on the other hand, there are quite a few choke points on East coast J-curve, where all kinds and classes of traffic gets funnelled - a real Russian Roulette situation. You'd think it might be a good spend of CASA safety funds if all recreational aircraft were subsidised to SSR equip. Of course, it's not feasible to expect controllers to be traffic cops for Class G. But I'm looking forward to cheap ADSB In&Out for the masses - with TCAS. (Preferably voice-prompting, since, obviously, the V in VFR needs less, not more, screen time..)

 

 

[dutchroll]

I suspect the military air defence radars would give a height, however I don't know this for sure and I would also be surprised if their normal controllers could access this, that's more the role of the air combat officers.

You're quite right in those assumptions.

Military Air Traffic Controllers and Air Combat Officers speak different languages! Totally different training paths and quite different system capabilities.

 

 

[ian00798]

I guess ultimately for one the job role is to keep aircraft separated, the other one their job is to put aircraft together.

 

 

[KRviator]

Last weekend I did the first flight of my RV overhead Cessnock and was passed as traffic to a departing Citation, with the Centre call being along the lines of VFR overhead Cessnock, southbound, altitude 4100 unverified, intentions unknown.

 

I called Centre and told them who I was and what I was doing, but it made me think about the caveat "unverified" in relation to my altitude. Presumably, that is because I was not talking to Centre and so he couldn't be sure I was as high as my transponder was saying I was. So in cases like that, is it better to pipe up and let him know what I'm doing, or simply remain silent and monitor for potential conflicts?

 

 

[Pearo]

Last weekend I did the first flight of my RV overhead Cessnock and was passed as traffic to a departing Citation, with the Centre call being along the lines of VFR overhead Cessnock, southbound, altitude 4100 unverified, intentions unknown.I called Centre and told them who I was and what I was doing, but it made me think about the caveat "unverified" in relation to my altitude. Presumably, that is because I was not talking to Centre and so he couldn't be sure I was as high as my transponder was saying I was. So in cases like that, is it better to pipe up and let him know what I'm doing, or simply remain silent and monitor for potential conflicts?

If I know center is referring to me I will always pipe up and state my intentions, if only for the benefit of the other pilot. I am always glad to hear ATC tell me of potential conflicts, and like it even more when the other pilot aknowledges also.

 

The plane I fly now has Traffic Information System, and its scary when you realise how much traffic you dont see. Since flying that plane, I have learned to always have Centre tuned in on the second com.

 

 

[rhysmcc]

Unverified just means the controller hasn't got an altitude report from the aircraft and cross checked the Mode C altitude from the transponder. This is usually done on first contact with a radar controller

 

 

[Jabiru Phil]

This is a great topic, learning from this.

 

Keep it up.

 

Cheers,

 

PHIL.

 

 

[ian00798]

I called Centre and told them who I was and what I was doing, but it made me think about the caveat "unverified" in relation to my altitude. Presumably, that is because I was not talking to Centre and so he couldn't be sure I was as high as my transponder was saying I was.

Exactly what rhys said. We don't know for sure that your mode c level is actually accurate, you may be on the wrong qnh, the transponder may be sending out incorrect data, all kinds of things so we let the other guy know that we don't have total confidence in the level information they are being given. It's the same as why most controllers use the phrase "intentions Unknown" when giving tracking information on VFR aircraft, we need the other guy to know that this traffic they are getting may behave unpredictably. For information, we will pass an IFR aircraft traffic on observed VFR aircraft that will get within 5nm and have a mode c level within plus/minus 2000ft.

 

As for whether or not to answer, it's a bit of a judgement call. If you hear the phrase "safety alert" or "avoiding action", it's probably a good idea to let us, and the other guy, know your intentions. I don't want to give avoiding action to an IFR aircraft only to then have you turn back into them. If it's just routine passing traffic, but centre sounds really busy, probably best to just stay quiet. If we really want to talk, we will chase you. If things seem quieter and you believe we are referring to you, by all means call up and let us know your intentions. The fact that you are listening on the area frequency even is a lot better than a lot of VFR pilots, and there is a lot of important info passed on the area frequency such as hazard alerts, traffic, military low jets, and weather updates.

 

 

[dutchroll]

Which reminds me of a question Ian: do you guys get the callsign readout of a Mode S reply even if the traffic is not formally identified? I presume this is the case, but I've noticed that on the couple of occasions ATC has wanted to talk to me regarding intentions, etc, the call is always preceded by "traffic 5 miles south of position x at 4,500'....centre". Is it the case that you can't address an aircraft by its Mode S rego until you've actually identified it (eg in case they've got the wrong rego set in the transponder or whatever)?

 

I've heard Centre give VFR traffic to an IFR aircraft including the callsign and altitude without verification but specifying that it was an ADSB paint, so presumably the VFR aircraft had operational ADSB Out.

 

 

[rhysmcc]

I've never seen Rego from transponder on my screens and don't have access to ADSB read outs other than on the ground. Not sure what the Enroute guys get to see.

 

 

[dutchroll]

Interesting. As quite a big deal is made of having that rego set correctly in a mode S transponder.

 

 

[shags_j]

I am pretty sure we don't get the callsign unless it's adsb and in proximity to an adsb receiver