123 Flinders Street and the Airport discussion

[[Shuz]]

Something tells me that the 135m 'threshold' is based on the AAL height limits, not the CASA limits, meaning thats as high as they can go without having to seek approval from AAL - pretty sure there's an airport height limits map around here somewhere to back this up.

*EDIT* - Seems like I'm on the ball with this one. Just checked out the Height Limits submission Sensational Adelaide made to State Government and the City Council in relaiton to the ACC Development Plan Review 2008. (see attached) and go to page 15 for the AAL Height limits map. You'll see where the corner of Pulteney/Flinders Street intersection is also smack bang in the middle of the 130-140m height limit contour - hence 135m for this proposal.

To summarise, they can go taller - just have to seek approval from AAL.

[claybro]

Can someone on here explain to me why, given the government went to the trouble removing the city council height restrictions, they have not gone to the AAL and asked to be given a block by block description of exactly what height is possible in the city, rather than the developers having to go cap in hand and beg on each application beyond the dizzying height of 40 storeys? I also do not understand how a plane in trouble, flying from due East (would not line up with any runway) could clear the 700m MT Lofty and supposedly crash into a 200m building? If a plane has decended from 700m to 200m in that distance, unfortunately it would not make the airport anyway.

[Nort]

Can someone on here explain to me why, given the government went to the trouble removing the city council height restrictions, they have not gone to the AAL and asked to be given a block by block description of exactly what height is possible in the city, rather than the developers having to go cap in hand and beg on each application beyond the dizzying height of 40 storeys? I also do not understand how a plane in trouble, flying from due East (would not line up with any runway) could clear the 700m MT Lofty and supposedly crash into a 200m building? If a plane has decended from 700m to 200m in that distance, unfortunately it would not make the airport anyway.

There is a map of AAL height limits. A developer can ask permission to go higher on a case by case basis and it will be assessed if that can be accommodated. Those permissions are better to be assessed individually since I assume one consideration will be the heights of other buildings in the area and thus they could chance.

Aircraft don't pass by the CBD from the East, they also come in directly from the North, over North Adelaide. The impact of a tall building is much larger than you might expect since air traffic has to maintain both horizontal and vertical separation from it.

All that said, it's obvious that it could be made to work, after all there are plenty of airports worldwide with much taller buildings near approach paths. However there are problems that need to be worked out to allow that to happen, so until there is a significant push by a developer really wanting to break the limits (and the government thinking it is a worthy project) you aren't going to see it encouraged.

[[Shuz]]

To further support what Nort has said, the issue is CASA (Civil Aviation Safety Authority), not AAL (Adelaide Airport Limited). We already know what the Adelaide Airport height limits are. This map can be found on page 15 of the attachment I uploaded a couple of posts previously.

An applicant can propose to go taller, they just have to seek development approval from AAL as well as the State Government DAC. Usually this isn't a problem at all. Westpac House is proof of this. It lies within the 100-110m AAL height limit zone whereby AAL also has to grant development approval but is 132m tall.

The issue is CASA.
Whilst we do know that CASA enforces a blanket 300m AHD height limit across the whole of Australia, whereby you have to get development approval from them as well as the airport (AAL), as well as the governing body in charge (city council, or in our instance the State Government DAC).

In the case of Adelaide and Sydney, because of the city's close proximity to the airport, it is different. The PANS-OPS diagram on page 14 of the attachment shows the CASA (PANS-OPS) height limits. This information should be clear as day? Unfortunately, for the most part of it, it is illegible. You can just make out that there is a 200m height limit over some parts of the eastern CBD. (hint, Datong, Paul Prusinksi, etc. hint) but as for elsewhere, whose to know. I've only ever personally witnessed an A4 map of the height limits that's pretty blurry and thats as much as they'll publicly show you and me.

As far as I am aware, a developer has to go to CASA, pay a hefty fee to find out whether or not they can build up to x metres tall. There's another problem in the process - CASA don't tell applicants or developers "Hey mate, thanks for the fee, let's look-see here, ah, you can build up to y metres at this spot". They just get a simple yes or no answer. If the answer's no, one has to pay the fee again with a lower value in mind and they will just tell you yes or no again. Why would one spend their time, effort and, most importantly money, knowing full well you run the risk of getting a no answer and have to pay the fee again just to find out. They aren't the least bit helpful in the process.

Hope this makes sense and clears things up for our fellow forumers. We'll try and stick to 123 Flinders Street news from now on.

[Maximus]

Shuz -- sorry, one more post on this.

The final decision actually rests with the Federal Department of Infrastructure and Transport, not CASA. The application is made through the relevant airport, and then CASA and Airservices are invited to comment before the proposal is sent to the Department for assessment and approval.

More information here.

[bm7500]

Just for a little more context. I was once shown the PANS-OPS maps for Brisbane airport whilst on a tour there a few years ago. The single biggest factor in making decisions around the Obstacle Limitation Surface (OLS) being penetrated is that CASA need to cater for the rare scenario of a large jet transport having an 'engine out' event. This would have the impact of reduced power and possibly some limitations in control and rate of climb.

Having said that, any tall structures that are approved will be clearly identified in the Jeppesen charts for Adelaide Airport.

[ghs]

I don't want to be negative but this building has not even been designed yet. We still have a very long
way to go.

[Howie]

Paul had something interested to add to this conversation around CASA and building heights.

Some facts:
1. You dont pay a fee to CASA.
2. CASA by law has to recommend refusal to DOTARS for any building that is either above the OLS or not shielded in accordance with the relevant MOS (memorandum of safety), which is referenced by the Aviation Act.
3. Air Sevices Australia control the space between the OLS and Pans Ops. Its got nothing to do with DAC or any state governement department. ASA also make a recommendation to DOTARS, and if the building is below the Pans Ops, the recommendation is likely to be positive albeit with some conditions.
4. Pans Ops levels change very regularly, so there is no long term map that can be used to determine it.
5. The CBD is right in the path of a departing aircraft with engine trouble, so DOTARS will seek expert opinion on the likely danger of any bldg on emergency aircraft activity. For those that have been on the roof of westpac house, you will realise just how close departing aircraft are above that building under normal conditions.
5. I cant see any politician asking DOTARS to approve a bldg that an aviation expert considers to be dangerous to air traffic, so political influence isnt a solution to this. There are only a very small number of recognised aviation experts in Australia, maybe 3 or 4.
6. DOTARS has the power to over-ride a planning approval and a building approval, and can order demolition, even after DAC has approved an application. The State Government has no authority over any of the federal departments that control these processes.

Unfortunately, the chances of a building busting through 140m in the mid term future is close to nil.

[rhino]

5. The CBD is right in the path of a departing aircraft with engine trouble,

Why? Most aircraft, whenever I have flown out of Adelaide, take off over the gulf. If an aircraft is taking off towards the northeast, and encounters engine trouble, I assume it has to get out of the way of any incoming aircraft, but why not veer north, rather than towards the city? I'm not doubting what Paul is saying, I'm curious.

[claybro]

Have to agree, the runway runs SW-NE, not due East. Why would an aircraft in trouble on take off veer sharpleySouth East and head straight for the 700m high Mt Lofty, let alone the CBD to turn around only not to line up with the runway again?. Im no expert onthis, but that does not make sense to me.

[Wayno]

What if the aircraft departing towards the NE has a problem that disallows it from turning left? and can't gain altitude? a rare occurrence indeed, but possible.

[Maximus]

What if the aircraft departing towards the NE has a problem that disallows it from turning left? and can't gain altitude? a rare occurrence indeed, but possible.

Exactly, Wayno. If it's the starboard (RHS) engine that goes out, the pilot will have enough trouble keeping the aircraft straight, let alone trying to turn left.

I think we all just need to accept the fact that these rules have been in place for a long time and for a good reason, and are set by people who know a lot more about the topic than any of us.

BTW, Howie, you might like to remind Paul that DOTARS is now actually DOIT. Very important that you know your acronyms here in Canberra.

[rev]

What if the aircraft departing towards the NE has a problem that disallows it from turning left? and can't gain altitude? a rare occurrence indeed, but possible.

Exactly, Wayno. If it's the starboard (RHS) engine that goes out, the pilot will have enough trouble keeping the aircraft straight, let alone trying to turn left.

I think we all just need to accept the fact that these rules have been in place for a long time and for a good reason, and are set by people who know a lot more about the topic than any of us.

BTW, Howie, you might like to remind Paul that DOTARS is now actually DOIT. Very important that you know your acronyms here in Canberra.

So how does that affect the southern half of the CBD/City?
The northern half which is closer to the flight path already has several buildings of 100m+ and many 50m+.
A 135m building in Flinders St isn't going to affect flight paths, when the three-four tallest buildings are north of it by several blocks and closer to the flight path.

[monotonehell]

5. The CBD is right in the path of a departing aircraft with engine trouble,

Why? Most aircraft, whenever I have flown out of Adelaide, take off over the gulf. If an aircraft is taking off towards the northeast, and encounters engine trouble, I assume it has to get out of the way of any incoming aircraft, but why not veer north, rather than towards the city? I'm not doubting what Paul is saying, I'm curious.

The direction of incoming and outgoing flights depends on the prevailing wind conditions. Some days they take off toward the hills and come in via the gulf, most days the opposite.

I used to work in the Telstra building, and some days they did fly very close.

[rev]

5. The CBD is right in the path of a departing aircraft with engine trouble,

Why? Most aircraft, whenever I have flown out of Adelaide, take off over the gulf. If an aircraft is taking off towards the northeast, and encounters engine trouble, I assume it has to get out of the way of any incoming aircraft, but why not veer north, rather than towards the city? I'm not doubting what Paul is saying, I'm curious.

The direction of incoming and outgoing flights depends on the prevailing wind conditions. Some days they take off toward the hills and come in via the gulf, most days the opposite.

I used to work in the Telstra building, and some days they did fly very close.

Over North Adelaide correct?

I still don't see how that should affect the southern half of the CBD.
This proposed building and revised height/floors, will not be in the path of planes.
You have north adelaide/flight path, existing tallest buildings, then this proposal.

I once posted an example from America, which had taller buildings, with a flight path from a much busier airport, running practically parallel to their skyline.
The southern half of the CBD is where development should be focused, with or without flight path issues elsewhere.

I've held this view for a while, and I still hold it. The airport & parafield need to be relocated to the salt pans. It is surrounded mostly by industrial sites, and mangroves/torrens island. Aircraft noise will be minimal to residential.
But it's never going to happen because of shortsightedness.