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shags_j

ATC Question Thread

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On one of the previous points. Of you are xcountry please listen out on area. So many times we have had a vfr aircraft going into an active restricted area or conflicting with ifr traffic and need their intentions but had no response from the vfr.

 

 

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Enroute don't see the callsign unless you also have ADSB out capability. I believe the system still receives all the mode s information, it just doesn't show on the screen for us. However, I believe the systems supervisor does have the ability to access the 24 bit mode s return from the raw feed if necessary. That is starting to really get into the technical aspects of the eurocat system and beyond my knowledge and most controllers knowledge.

 

I believe the mode s data becomes more important at certain towered aerodromes when they use a system known as A-SMGCS for ground movements, and I believe this system is largely reliant on mode s information, hence the requirement for mode s at places like Sydney and Brisbane. Having the correct mode s callsign would be critical here. Not being a tower controller, my knowledge on this system is very small, perhaps Rhys can elaborate a bit on that one.

 

 

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Enroute don't see the callsign unless you also have ADSB out capability. I believe the system still receives all the mode s information, it just doesn't show on the screen for us. However, I believe the systems supervisor does have the ability to access the 24 bit mode s return from the raw feed if necessary. That is starting to really get into the technical aspects of the eurocat system and beyond my knowledge and most controllers knowledge.

I believe the mode s data becomes more important at certain towered aerodromes when they use a system known as A-SMGCS for ground movements, and I believe this system is largely reliant on mode s information, hence the requirement for mode s at places like Sydney and Brisbane. Having the correct mode s callsign would be critical here. Not being a tower controller, my knowledge on this system is very small, perhaps Rhys can elaborate a bit on that one.

Indeed the Surface Movement Radar at places like Brisbane, Sydney and Melbourne displays your Mode S callsign, we often get error messages if the callsign and the code assigned to your flight plan don't match.

 

Yeah I've heard guys called on taxi and asked to recheck their flight # ID.

Yeah, we will ask you to check the callsign in your FMS or if you are squaring the wrong code you'll get a reminder of the correct code. It happens a few times a day with the airlines often having to change callsigns or forgetting to put in the new code.

 

 

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Yes, I've wondered what info ATC can see when I fly...

 

My transponder is a Class 2 mode S with extended squitter (TSO c166b compliant) with my correct hex code. My GPS source is not fully TSO'd and shows the following integrity in the data stream:

 

SDA: 1/ SIL: 1

 

NACp: 8, 9 or 10. Dynamic, as reported by GPS.

 

NIC: 8 (Containment radius <0.1 NM)

 

NACv: 1 (10m/s accuracy)

 

Does ATC see more data on your screens after a squawk ident is done ( ie. typically when I'm doing skeds over Bass Strait?).

 

What do you see? (Note to self... Must do a tower visit one day...)

 

Happy flying everyone!

 

 

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Yes by the 4th domestic sector of the day with all different flight numbers (which is normally our limit) it starts getting difficult to remember who you are, I can assure you! 003_cheezy_grin.gif.c5a94fc2937f61b556d8146a1bc97ef8.gif

 

On the subject of squawking ident, if I recall my Officers Mess bar conversations with our military ATCers many eons ago, I think it just temporarily changes the symbology to a far more prominent indication, rather than giving any extra data. Then again, we used to drink a lot at the bar so god knows what they really said........

 

 

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Don't worry I sometimes forget the chair I'm in too :)

 

Your correct, squawk ident makes your return flash pink on our radar display, easiest way to make sure we have the right 1200 code when giving traffic/info too, not sure what extra info is sent to the system, nothing we see other then the colour change

 

 

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In the enroute system it will flash cyan. Rhys, is your tower intas yet?

Nope Eurocat and old school paper strips

 

 

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Hi All,

 

Great idea on the thread- very informative :-)

 

I was wondering what the protocol is regarding altitudes when flying near controlled airspace. I'm a relatively low time pilot (~50hrs) and I had one flight flying towards the Q1 on the Gold Coast from Boonah where I was asked my intentions by Brisbane Centre. They identified me by location and altitude but the altitude they used (mode C or radar I guess) was about 200ft higher than my altimeter read, even though I'd got the area QNH from the controllers about 10 minutes earlier. I was wondering if in this case if I should have checked the QNH with them again or let them know I had a disparity? flying under the 1500ft class c step to the coast I wanted to make sure I maintained 1000ft above the populated areas but not too close to class c above. Any suggestions would be very helpful :-)

 

Thanks!

 

 

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Does your transponder have an altitude readout? That would be the quickest way to cross check. Were you using Area QNH from the forecast or did you get actual QNH from Gold Coast ATIS (they may not be the same)?

 

You may have been heading towards the Control Zone so the controller may have being proactive to arrange clearance or keep you clear. Don't be afraid to ask for the QNH and a level readout, if you find your always out maybe get it checked? ATC apply a 200ft buffer for error/tolerances.

 

 

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Hi Rhys,

 

Thanks for the quick reply. No readout on the transponder but I'm pretty sure I was on area QNH that I it from Brisbane Centre. Either way it's good to hear that there's a buffer to correct for any issues with equipment.

 

Cheers

 

M

 

 

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Either of you guys have the sector for far northwest NSW OCTA? Had two very helpful and good controllers that way recently.

 

 

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but the altitude they used (mode C or radar I guess) was about 200ft higher than my altimeter read, even though I'd got the area QNH

do they adjust the mode C data for QNH or just use the pressure altitude from the encoder? I believe the output is in steps so that data may be some way off the pressure altitude sensed by the encoder too?

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image.png.0532dfc30d067f01dbc556ab6312a6c5.png Just ordered my Foxbat & have the following transponder fitted, see the explanation, the altitude ecoder is locked in at STD i.e. 1013 regardless of what you enter on the altimeter, therefore you will get some disparities with large QNH changes, IFR a/c will have the altitude selector wired in to the transponder i.e. Correct altitude when on QNH then correct level when STD is selected, well that's what happens on the Bus.080_plane.gif.36548049f8f1bc4c332462aa4f981ffb.gif

 

Doubled up on the attachment, finger trouble 079_throw_pc.gif.e071c8f36d135c7f050383c74279afc6.gif

 

image.png.f7a1b3a28f64c1d6a2858cb53f88d58c.png

 

 

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Ben87r ian And i are both on that sector (127.1).

Yep that's the one. I've flown through LRD WLG a few times recently in a PA30. Each time needing the bother you guys with a flight plan amendment or the like. Very pleasant time out that way! Good work.

 

 

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[ATTACH]42521[/ATTACH] [ATTACH]42520[/ATTACH] [ATTACH]42521[/ATTACH] [ATTACH]42520[/ATTACH] Just ordered my Foxbat & have the following transponder fitted, see the explanation, the altitude ecoder is locked in at STD i.e. 1013 regardless of what you enter on the altimeter, therefore you will get some disparities with large QNH changes, IFR a/c will have the altitude selector wired in to the transponder i.e. Correct altitude when on QNH then correct level when STD is selected, well that's what happens on the Bus.080_plane.gif.36548049f8f1bc4c332462aa4f981ffb.gif

Doubled up on the attachment, finger trouble 079_throw_pc.gif.e071c8f36d135c7f050383c74279afc6.gif

Is the Microair transponder ADSB ,mode S or just mode C ? anyhow when I read about it I cant find anything about mode S.

 

I thought all new aircraft were to be fitted with mode S capable transponders.

 

 

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Just looked at my purchase order & I'm getting a Mode S transponder, my error I assumed it's a Microair that was in previous a/c, you're right all new a/c generally come with Mode S these days if you want a transponder, however if you are unable to enter controlled airspace i.e. You only have RAA qualifications the older Mode C version is still handy & a lot cheaper, this will allow you to use flight following on cross country flights.080_plane.gif.36548049f8f1bc4c332462aa4f981ffb.gif

 

 

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I'd go the whole hog with a transponder, even though you can still buy the cheaper Mode C only variants.

 

The problem is this: you never quite know when the regs will become more restrictive (as they're tending to do with transponders and ADSB), and also you never quite know where you'll be inclined to take your little plane in the future as far as controlled airspace goes.

 

If you get a Mode S, "ADSB capable" transponder (this doesn't mean you actually have to buy the GPS equipment - just that you can add it later if you want) you are fairly bullet proof for the future.

 

 

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Yep that's the one. I've flown through LRD WLG a few times recently in a PA30. Each time needing the bother you guys with a flight plan amendment or the like. Very pleasant time out that way! Good work.

I think I actually remember this aircraft, it's not actually that common for us to get a twin Comanche in our airspace. Don't worry, your plan amendments weren't too hard, the low level sectors get very good at dealing with flight plans.

 

 

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Well I'll be back out that way this coming Saturday afternoon/evening planning LRD WLG ORG through that bit of the flight. Ill say G'Day.

 

 

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