ATC Question Thread

[ben87r]

ICS.

 

 

[dutchroll]

Intrepid ATCers......

 

Debate raging on company forum (in a humorous way, but it's on page 4 now and has suffered thread drift with lineup and takeoff clearances):

 

"(Callsign) when ready, descend to ........."

 

Is it necessary to read back "when ready"? I would suggest no it is not and I never do, nor do many I fly with. One or two are trying to say that this is a conditional clearance, but I'd disagree. There is no condition attached. Controller is just saying in effect "descend whenever you like - I don't care at the moment". Thus the normal requirement to initiate descent within one minute of receiving the descent clearance does not apply.

 

The question originated because one of the guys recently had a controller insist he read that bit back. First time I've ever heard of that happening.

 

 

[ian00798]

No requirement to read back when ready, and it will drive me nuts if people start doing that. It's not a conditional clearance, if anything it waives the condition to commence descent within one minute that you would get with a normal descent instruction.

 

A conditional clearance would be along the lines of "at 25 miles to run Armidale, leave control area descending". I can't imagine any controller using that though, too much can go wrong and it doesn't really assure separation.

 

 

[Camel]

Just looking up Tamworth and am a little bewildered !

 

It seem you can only approach from Duri Gap.

 

Can you enter from North and East as there are no reporting points there ?

 

 

[rhysmcc]

Sorry I can't help too much (not familiar with Tamworth). ERSA suggests an arrival procedure tracking via Duri Gap if coming from 160R to 295r. No mention of any other arrival procedure outside of that arc, however it doesn't indicate that you MUST approach from direction.

 

There is a remark for unfamiliar pilots to contact the tower for briefing prior to departure. I can only assume the Duri Gap procedure is about operating the 2 different circuits with separate tower frequencies and controllers? Maybe give them a call or failing that call inbound for a clearance, if they tell you to expect inbound from Duri Gap you'll know you need to go the long way around?

 

 

[SDQDI]

Just looking up Tamworth and am a little bewildered !It seem you can only approach from Duri Gap.

Can you enter from North and East as there are no reporting points there ?

I can only speak from my limited flying from tamworth when doing my RAA navs.

From the south (the actual bearings are in the chart) duri Gap is the only approach but from my understanding the northern side you can come from any angle BUT my experience is limited to coming in from Gunnedah and each time we went over lake keepit to get above the required bearing (which basically gets you out of the road of gate west departures) and we were told to fly over somerton or bective.

 

I think the main reason for limiting access from the south is to ensure a safe separation between their arrivals and departures remembering that tamworth does NOT have radar under 4-5 thousand feet and to the south the topography limits safe access at 3000ft to the south to 3 narrowish points (1=gate west, 2=duri gap, 3=gate south) so instead of having conflicting traffic squeezed together they have adopted a sensible procedure to basically have one way traffic at each of those three points which also has the benefit of giving the controllers a definite point to spot incoming traffic (remembering no radar)

 

 

[ian00798]

I think the main reason for the standard procedure with duri gap/gate south/gate west is to have it so all the aircraft going to/from the training area have some form of strategic separation, as a lot of training happens there and you really need to keep the VFR apart. Remember, it's class D, so the tower isn't actually separating VFR from VFR (except runway separation), you will only get traffic information. And for practical purposes, Tamworth tower doesn't have radar below 8500 feet as they are not a radar tower and can't use radar for separation, it's only a situational awareness tool. Brisbane centre does use radar for separation there, and normally around Tamworth we will have aircraft on radar by 5500ft. Even then, to seperate with radar we need to establish a positive identification, which is a process way beyond the scope of this thread.

 

With class D, you can actually attempt to come in from any direction, you don't have to use VFR approach points. However, there is also a good chance if they are busy the tower will tell you to expect clearance via one of the published points, and with Tamworth the duri gap procedure is a special procedure in ERSA and must be used if your between those radials. If your outside those radials then you don't use the procedure. Use something obvious, like inbound via Inverell, Armidale or a radial if possible. There are also lots of other visual features you can use, such as keepit, bective homestead, sommerton, Manila etc.

 

 

[dutchroll]

No requirement to read back when ready, ......

I think we've put the argument to bed (as much as that's ever possible among a group of pilots) on the other forum, but interestingly it has emerged that there is a loosely scattered group of junior controllers who are insisting on a "when ready" readback from pilots, but there is also a group of senior controllers trying to correct them and informing them it's not necessary.

The reasoning apparently given by one of the errant juniors was "well I need to confirm that he understands he's not required to descend straight away". I think that's poor reasoning from the junior guy. It's really the pilot's problem if he starts his descent early when he doesn't need to. It's not a safety issue as the descent clearance is valid either way. He'll just need to shallow out his descent profile, and there'll probably be a guy next to him muttering "See? I told you it was when ready!"

 

 

[facthunter]

Confirming the descent clearance is the main point. (hoping to prevent you descending without one.) "When ready" must include straight away (logically). If they put a condition on it, say specifically "not less than standard rate" which is implied anyhow, I would still see that as needing to be read back if a controller wanted to state it. Nev

 

 

[Pearo]

Just a quick question, not relevant to area controllers though. When transiting CTR , you request clearance at or around the reporting points (thinking Gold Coast and Sunshine Coast here), ATC normally ask to report at the zone entry and then abeam the airfield. Sometimes they just give you clearance with no request to report position, and I can tell that it's always when they are really busy. I always give a courtesy call abeam the airfield. Should I just shut up and keep flying?

 

 

[rhysmcc]

I don't work at either but I'd say if they haven't asked to you report.. Don't. Sometimes when it's quite asking you to report prompts us for next action (i.e. Your next tracking.)

 

I should add, if unsure speak up better to do too much than not enough :)

 

 

[Pearo]

I don't work at either but I'd say if they haven't asked to you report.. Don't. Sometimes when it's quite asking you to report prompts us for next action (i.e. Your next tracking.)I should add, if unsure speak up better to do too much than not enough :)

I pipe up at Sunny Coast more, because when you report abeam they normally then say report clear of the zone. Gold Coast (SSR) is a little different obviously.

 

Next time I will just report clear of the zone unless requested otherwise!

 

 

[frank marriott]

I pipe up at Sunny Coast more, because when you report abeam they normally then say report clear of the zone. Gold Coast (SSR) is a little different obviously.Next time I will just report clear of the zone unless requested otherwise!

Unless requested, why would you report clear of the zone?

 

 

[Pearo]

Unless requested, why would you report clear of the zone?

Good question, but seems to be the case for the non metro class D airports. Metro Class D never request it.. Time for me to research the AIP, I am just parroting what I was taught.

 

 

[rhysmcc]

So your control services are terminated and your frequency change approved :)

 

 

[ian00798]

Pearo, it really depends on whether you are in the CTA or the CTR, as there is a difference between the two. If your going into the sunny coast CTA, you should give a position report overhead the aerodrome, ie abc position Sunshine Coast at 35, 3500, Gympie at 05. When your in the Ctr, just give the reports that tower ask for, nothing else, as VFR in class d ctr have slightly different rules to the CTA when entering from, or exiting to class g airspace. If I recall correctly, the sunny coast Ctr is at or below 1500ft, above that is CTA

 

 

[dsam]

New ATC question regarding Bass Strait "Skeds":

 

Special procedures 1.2.1b says to nominate 10, 15, or 30 minute reporting as appropriate to the speed of the aircraft - (with no further detail).

 

I'm puzzled... why would speed matter? For a cruise TAS of 110 knots, which option should I request?

 

 

[SDQDI]

Just a guess Dsam as I am NOT atc.

 

I would say, if you were in an aircraft doing 200 knots, reporting every 30 minutes would not give a very accurate picture of your progress inasmuch as you would nearly be there by the time your first reporting time came up and on the other side of the spectrum if you are doing 50 knots reporting every 10 minutes will be pointless as you wouldn't have travelled far from your last point.

 

As for something traveling at 110 I would guess that 15 minutes would be reasonable.

 

 

[shags_j]

Not being on Bass Strait I am unsure the actual reason though what SDQDI says is probably very close to correct.

 

 

[ben87r]

Gents, how come around Sydney, Adelaide etc but I'll use Sydney as my example, I'm passed on to "Sydney center" and sometimes "Sydney Radar" (possibly others) being the same freq?

 

Does it matter how they are referred to after first contact? Because I nearly always end up calling them "center" in later calls after forgetting it was radar.

 

 

[Jaba-who]

I have another question for the ATC guys but it's actually about in class G airspace so maybe not appropriate here. But it's turned people inside out on Facebook Australian Pilots Lounge and still no answer.

 

Situation: At & in vicinity of a rural airport with mix of GA & recreation pilots some pilots routinely give their position reports in feet AGL ( I have heard one giving "3500 ft AGL" but some just in feet without the "AGL". Airfield elevation 2500 ft so when they give height as 1000 ft it's obvious they men AGL but anything over 2500 ft could be anything. Calls are not always just in circuit some are several miles from airport.

 

I had an episode where I made a call that I was at 4500 ft ( meaning I was at 4500 ft AMSL ) tracking for a nearby airport and had a response from a pilot that he was on reciprocal track same area but " well below me". Almost instantly I had a windscreen full of trike and evaded a collision with some hefty banking. His response was " you were not at the altitude you said you were. You were at 2000 ft. Get your act together" so he assumed I was saying altitude AGL not AMSL.

 

I was too stunned to answer or find out who he was.

 

So I want to bring this up at aero club and get it written up in the newsletter to tell people to use AMSL in radio transmissions. We all know that we should be on the same page - using the same reference datum and that the only one that is known to all is AMSL based on an altimeter set to QNH. But the pilots involved have for some reason decided they don't want to do that. But I know better than bringing this up without having the legislation reference. There are plenty of anti-authoritarian pilots around who will get their backs up so I need the regs to back me up. Trouble is it seems that no one ( especially me) can find such a reg. Everyone has found regs that say you have to set the altimeter to QNH etc but that's not saying that what is said on the radio has to reflect what the altimeter says.

 

Anyone know or can point me to the ACTUAL regulation that dictates the words that must be said. I'm not interested in hearing about AIP 1.7 2.1.2 that says you have to set the altimeter to QNH. That's not the question. It's what do the rules say you must speak on the radio when giving an altitude.

 

Any help?

 

 

[ben87r]

The only help that I can be is, if you are after a regulation the AIP is USUALLY no help but, CAR 82A says

 

" casa may give direction to words or phrases used and this will be in the form of the AIP or NOTAMS" or close to that anyway as I can't paste it. This now makes not adhering to the (I us jepps) communication section, or AIP, a breach of 82A.

 

Then in the AIP somewhere (AU 915.6.1.5 for jepps) in the communicationssection that the "following information whilst primarily for controlled airspace should use these phrases unless specific class G procedures are shown."

 

Then 6.3.3 goes on to say that " reported level figures must be preceded by flight level when referenced to standard pressure and feet when referenced to QNH"

 

That now making using feet with anything apart from QNH In breach of 82A.

 

Also there is not reference to AGL that I've seen in my late night reeding of it so therefore, wouldn't be directed by casa.

 

I apologise for the jepps references but I don't even know how to spell AIP let alone cross reference them.

 

So it's kind of an asre about way of getting there but if they were to prove that wrong they have more time and effort to put into it then I have. But with that now out for all of the Internet to see I'll imagine someone will come up with something, and my bet is the legal definition of should.

 

 

[ben87r]

Just had a google of the definition of should, found the following link. Post # 14 gave me a good giggle.

 

Legal meaning of "should" vs "shall" - Straight Dope Message Board

 

 

[Aldo]

I have another question

Jabba

 

From what I can find AIP ENR 1.7-2.1.2 (sorry for the reference) says the following

 

For all operations at or below the transition layer (in the altimeter setting region) the altimeter reference seething will be

 

(a) the current local QNH of a station along the route within within 100nm of the aircraft or,

 

(b) the current area forecast QNH if the current local QNH is not known.

 

Also fig 1 shows what subscale you should be on at each phase of the flight.

 

Therefore by deduction if you were to to announce your height if would then be AMSL as you are reading your height from the altimeter.

 

I do understand your situation though as I have the same problem here (although they are mostly below 200 feet so well out of my way - try to school them on the dangers of that and you will get a mouthful also) and also some of the local pilots refuse to monitor either the local CTAF or area frequencies but are instead on the chat channel 123.45

 

If you say anything you are the worst person in the world so short or reporting them I just give up trying to educate them and monitor all three

 

Aldo

 

 

[Jaba-who]

JabbaFrom what I can find AIP ENR 1.7-2.1.2 (sorry for the reference) says the

 

Therefore by deduction if you were to to announce your height if would then be AMSL as you are reading your height from the altimeter.

 

I do understand your situation though as I have the same problem here (although they are mostly below 200 feet so well out of my way - try to school them on the dangers of that and you will get a mouthful also)

 

Aldo

Well no you can't and that's why that reference is not useful. That reference says nothing about phraseology or information that must be stated on the radio. Just as you have deduced it does, these guys may or already deduce it does not.

 

This guy may well say, " I set my altimeter to QNH completely in line with the law. I deduct the known airfield height, or my GPS derived ground elevation below me, or that I think I know the ground elevation below me, from the QNH derived altitude and give my position as a calculated AGL and there is nothing in the law that says I can't. "

 

And so far it appears he would be right. No matter how stupid it might be.

 

Part of the problem may be that we have a crop duster here who gives his altitudes as " operating not about 500 ft" which is probably reasonable though I don't know if it's legal. He thinks it is because he told me it was in the rules. But didn't tell me where.

 

But given he is on air frequently and is a commercial pilot then I suspect a lot of the recreational pilots copy his techniques but don't appreciate there is a major difference between " not above 500 ft" and "3500 ft AGL" in terms of safety and potential collisions.