Lord Mayor calls for higher buildings in Brisbane's CBD

Lord Mayor Graham Quirk wants Brisbane to aim higher, calling on aviation authorities to relax tough restrictions that limit CBD developments to 274 metres.

Cr Quirk said the enforced ceiling on the city centre had the potential to stifle economic activity, as he called for a relaxation in the restrictions to allow for heights of up to 300 metres – nine metres shy of the tip of Sydney Tower, formerly known as Centrepoint Tower, the city's tallest structure.

"It's really not for the now; it is for the future, but that future is fast coming because we've already got a few applications in for 274 metres, so it's not far away when we're going to have people knocking on the door wanting to go higher than that number," Cr Quirk said.

The Brisbane Skytower, currently under construction on Margaret Street, will be the first building to reach the 274-metre ceiling when it is completed, expected to be in 2018.

The only way is up: an artist's impression of Skytower, which is scheduled to be the first Brisbane building to reach 274 metres. Credit: Chris Powell

Development applications for 274-metre towers have also been approved for 155 Edward Street, 240 Margaret Street and 30 Albert Street.

Cr Quirk said those towers showed there was a hunger for higher towers in Brisbane and the city could miss out on economic activity if restrictions stayed in place.

"We don't want to reach a point where we'll have to turn employment opportunities away from the city by saying 'no' when someone wants to develop something that is higher than the current 274 (metre) limit," he said.

Cr Quirk said both the Civil Aviation Safety Authority and the Brisbane Airport Corporation had been "hanging their hat" on international aviation law in their opposition to increased building heights.

Brisbane's current tallest building, Infinity Tower, is not tall enough for our Lord Mayor. Credit: Robert Shakespeare

"I get the fact that we want to have a strong aviation safety record and we certainly don't want to jeopardise that – we're not about to do that and say 'let's throw safety out the window and have greater heights as a result'," he said.

"What we are asking, though, is that there be a sensible conversation around the flight paths around and the potential for, if not all, some parts of the city to at least be able to go higher."

The reason for the restriction

An Airservices Australia spokeswoman said a "number of components" were considered when determining the impact of tall buildings around Australian airports.

"These assessments determine the impact that the airspace penetration has on arrival and departure flight procedures and offers air traffic management information to the relevant airport and regulators," she said. "In this case that is Brisbane Airport Corporation and the Department of Infrastructure and Regional Development."

The spokeswoman said Airservices Australia's Radar Terrain Clearance Charts was a measure of how low aircraft could go relative to nearby infrastructure.

It is determined by calculating the height of the highest obstacle, rounding up to the nearest 100 feet, and adding another 1000 feet.

"Therefore, if an obstacle is 319.13 metres it is converted to feet, becoming 1047 feet, which is then rounded up to 1100 feet," she said.

"To meet the required separation standards an additional 1000 feet is added, making the RTCC height in that area 2100 feet.

"This means that the lowest altitude a controller can have an aircraft under radar vectors in that area as depicted on the RTCC is 2100 feet."

Brisbane CBD's 274-metre height limit is, in imperial measurements, 900 feet. That means the city has an RTCC – in effect, a horizontal plane over the CBD, under which aircraft can't fly – of 1900 feet (580 metres).

While aircraft would not usually fly that low over the CBD, along what pilots call the "River Track", air traffic control clearance could in some circumstances, such as emergencies, be lowered to 1900 feet.

Any change to building height limits could require revised flight paths or steeper angles of descent and ascent.

Most of the aircraft that use the River Track, heading east over the city towards the airport, are services arriving from the north.

International regulations mean any increase to the RTCC would have to be done in 100-foot increments (30.5 metres), but any changes would have to overcome significant regulatory hurdles.

Adding to the constraints is Brisbane Airport's new parallel runway, due to open in 2020, which would replicate the airspace requirements to an area two kilometres to the west.

Other restrictions, such as the departure surface (a gradient that gets higher the further away it is from the airport) also affects some sections of the CBD.

The case against raising the roof

A Brisbane Airport Corporation spokeswoman said while the BAC did not approve or declare protected airspace, it did not support changes to the existing regulation.

"BAC has an obvious interest in the protection of the airspace that enables Brisbane Airport to operate safely and to grow," she said.

"Nonetheless, we will continue to work with the federal government and the council to look for opportunities wherever possible within the established international regulations."

Council opposition infrastructure and planning spokeswoman Shayne Sutton said while Labor was open to a review of CBD heights, that should not come at the expense of air traffic safety.

"The existing height limits are the result of advice from Airservices Australia, and are in place for a good reason," she said.

"We would need to see clear evidence from ASA that the height limits are no longer required or can be increased."

Cr Sutton said the impact of any changes to height limits on flight paths and the resulting aircraft noise over Brisbane suburbs would also have to be fully understood before adoption.

"There are some key areas across Brisbane that are already adversely impacted by aircraft noise," she said.

"We will not support measures that intensify this problem, or spreads it over a greater number of suburbs."

But Cr Quirk said technological changes in aviation technology could allow for a rethink of the restrictions.

"There might be able to be a reduction of the aviation space over time, again that's in the unknown, but in dealing with what we have at the moment, what I'm saying is let's look and see if we can get at least some areas of the city where we might be able to go to at least 300 metres to provide some flexibility," he said.

That conversation, Cr Quirk said, should not assume skyscrapers in the mould of Dubai, which boasts the tallest building in the world, the 828-metre Burj Khalifa.

"We're not going to hit the Dubai levels – I always smile when I hear people say Brisbane's turning into Dubai because that's never going to happen," he said.

"But I would like to see at least a conversation around 300 metres. I think that would provide at least way forward for the foreseeable future."