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-   -   Holding at Brisbane (https://www.pprune.org/pacific-general-aviation-questions/588602-holding-brisbane.html)

Cralis 21st Dec 2016 21:37

Holding at Brisbane
 
Hi all,

Yesterday, there was a bit of a lightning storm over Brisbane around 17h00, and it looked like it maybe passed right over YBBN. I enjoy taking a look at FlightRader a few times a day, and noticed a lot of aircraft circling. This one in particular seemed to be travelling about a bit.


https://s27.postimg.org/82t0xp0qr/Sc...221_173838.png

Looked like he was initially going to 01, then told to go away for a bit (Technical term from a non-pilot), and then started another approach onto 19... then circle .. then go off to Moreton Island... and then come back. Would ATC have decided that?

I looked at the other aircraft, and most had been doing circles as well - none were going into Brisbane, but there were holding in different areas. One seemed to be close to Sunnybank, another over the bay.. and a few others further out.

I assume this was due to the lightning.

What's the danger with larger aircraft and lightning? I think there's been a couple of accidents due to lightning, but in general, it's pretty safe. Is that right? But because of a few issues, it's safer to wait for it to blow over?

Was there a wind direction change for this guy? Initially on for 01, and then they changed things up a bit?

And usually holding patterns look very neat. I saw a Qantas Link guy doing a lot of very square looking patterns all over the same place.. looked like one square, really. That was up closer to Sunshine Coast. Yet this guy seemed to be all over the place.

Are there holding areas around Brisbane? Or are you just told to hold there, with some form of instruction? Because there were guys all over the place. I'm assuming the ATC chaps get a bit busy at this point?

And for those neat holdings, is there a fix on the ground that you use to fly over, and then use timing to keep those patterns so neat?

Sorry for all the questions - just interested to see why this chap had a strange pattern, and how it all works here.

Thanks.

Flying Binghi 22nd Dec 2016 03:17

Yeah, the kero burner driver were probably just checking out his favorite fishing spots in the bay..;)

Jabawocky 22nd Dec 2016 04:41

Looks like he was holding because of a big pile up on the runway and taxi ways :-)

bw2004 22nd Dec 2016 08:00

The last two replies were amusing at least!
As I don't have anything more entertaining to add, I'll try and answer your question.

In short I suspect the path would have largely been driven by ATC. BN would have a number of points where ATC would ask you to hold.

As for the lightning, I suspect it would be the associated thunderstorm conditions +/- delays from other inbound aircraft that would have meant holding was necessary (rather than the lightning itself).

I should mention that I don't fly into BN so I'm sure the jet drivers that operate there could give a more comprehensive answer but that's a start I think!

Hope that helps. Cheers for being interested - the more aviation enthusiasts around the better for all of us.

Jabawocky 22nd Dec 2016 10:55

OK, to be fair there was a massive line of storms to the west of Brisbane that moved more or less South to North. The usual holding locations to the NW/SW etc were in very violent storm paths, so who knows what crews were requesting and ATC doing to accomodate them.

Nobody wants bent metal.

Cralis 22nd Dec 2016 11:10

Just asking, Jabawocky - not making any accusations or something here. I enjoy watching Flight Radar, and just wondered why that sort of thing happened, and how it happens.

ReefToppy 22nd Dec 2016 17:30

When there is bad weather about, the published holding patterns may not be usable to pilots. We hold acft wherever they can hold and adjust as needed for both weather avoidance as well as to achieve some semblance of a sequence to approach. At this time of year, it's always messy, and yes we certainly get a bit busy at this point. The patterns are usually much tidier when the weather is good.

mcgrath50 22nd Dec 2016 22:11

Question Reef, would that ugly pattern out to the east - south east have been a series of vectors or some sort of weird holding instruction?

Cralis 22nd Dec 2016 23:19

Thanks ReefToppy - That's pretty informative. So there's no designated holding areas really, and an aircraft can be told to hold anywhere, really? I was also wondering what mcgrath50 was asking, as that guy seemed to have a few changes to what he was doing, and heading out to the island seemed different.

strim 23rd Dec 2016 00:23

If you want to see an ugly holding pattern, try the Universal FMS in a 50+kt X/W

le Pingouin 23rd Dec 2016 04:05

I'd guess vectors given the straight sections.

ReefToppy 28th Dec 2016 21:40

For some reason I can't see the picture posted so I can't comment on the pattern you describe, but it's not uncommon to vector strange patterns when weather is involved. We do whatever we can to get a sequence and keep acft away from storms.

Cralis 28th Dec 2016 23:00

Sorry ReefToppy - I'm guessing you're blocked for accessing "postimg.org", which is where I put the photo.

Frank_The_Tank 29th Dec 2016 09:41

Hi Cralis. I operate in and out of Brisbane often, so I'll try and give you the best (guess) answers I can.

Rather than lighting, the biggest hazard to aircraft during take off and landing from thunderstorms is severe turbulence in the form of windshear. Although lightning is still a hazard, it is severe changes in wind which are most likely be detrimental to the safety of the flight when it is close to the ground.

There was likely an easterly sea breeze when the aircraft first approach so used 01. With weather in the area, for whatever reason - most likely windshear, it made a missed approach. After this point the duty runway changed to 19. The weather at the field would have initially been gusty and variable from the storm. Once the storm had moved east the sea breeze likely subsided to a light wind favouring 19. It looks like it was vectored by ATC to hold at a published GPS waypoint SINNK, where the standard "square" racetrack pattern is seen. This is something that can be pre-programmed into the flight computers and the aircraft will automatically fly a GPS based holding pattern - hence why it looks nice and square. It looks like it flew one pattern before (at a guess) I'd say the weather at the airport was moving east and shifted toward where it was holding. From there they likely requested vectors from ATC around the weather (picking a gap so to speak) before making an approach back onto 19.

Aircraft that have already made a missed approach are usually afforded priority to land first over later arriving aircraft (all the other aircraft you could see holding further out) as their fuel state is likely less.

There are specific GPS based waypoints for holding around brisbane - and all over the world for that matter. the Qlink plane you likely saw was holding at one of these. Others may have just been taking headings from ATC due to weather at at their intended published holding point. This looks quite messy on a radar plot but achieves the same result. As long as you can depart a specific point at a specific time to fit into the sequence, on a stormy day, it doesn't really matter how you achieve it.

Cralis 29th Dec 2016 22:57

Wow, thanks very much for that, Frank_The_Tank! That's incredible.

I play about with Flight Simulator, and starting to learn about the FMC. Things must get pretty busy when things change, like that. Everything all planned and then a massive change like that.

Amazing how you mentioned SINNK. In X-Plane, I use SINNK as the waypoint I need to get to to turn to 196 for RW 19. Was pretty nice to hear a real pilot mention that! I see on the FMC, there's a 'HOLD' button. Maybe that's used to 'easily' create a holding racetrack shape on a selected waypoint?

I divert. Sorry. :)

Thanks again for that response.


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