Posted on

Investigation: Increased use of north-west RAAF airspace

In May 2013, Airservices permanently implemented an alternative departure procedure from Perth Airport that reduces the number of aircraft flying low over north-western suburbs during the night. The permanent implementation of this procedure follows a trial that started on 27 July 2011 and was known as the ‘Keels trial’.

The new flight path allows some aircraft that previously departed late at night to the north of the airport and then turned towards the coast to make use of RAAF airspace to the north of the airport when the area is not in use by Defence. This change did not apply to all aircraft departing to the north, or change any routes for flights departing to the south.

Previously, most of these aircraft (mostly heading to destinations in the Middle East and Africa) overflew Beechboro and suburbs to the west of Beechboro at between 2500 and 4000 feet (760 to 1200 metres). The new flight path has some of these aircraft take a more northerly route and only turning after they reach 8000 feet (2400m). This additional height reduces the impact of aircraft noise on the ground. It also provides some night-time respite for residents in Beechboro and the suburbs to the west of Beechboro.

Following additional community consultation and environmental assessment, in July 2014 use of this procedure was expanded to all hours when RAAF Pearce airspace is not in use. This will continue to deliver improved noise outcomes for residents living in nearby suburbs including Beechboro, Malaga and Ballajura.

Read the Post Implementation Review of the trial

Posted on

Investigation: Helicopter activities

Filming at the MCG

Airservices followed-up complaints about helicopters hovering over the Melbourne Cricket Ground (MCG) during sporting events. Helicopter operators advised the low winter sun often prevents filming from the south of the ground during the AFL season. Therefore on-ground advertising during the AFL season is orientated so that it is best viewed from the north, which is why helicopters tend to hover to the north of the ground (over residential areas).

The operators agreed to hover to the south whenever possible, and when filming from the north they will try as far as possible to hover over the park north of the MCG and not over residential areas. In addition, operators already try to use their quietest helicopters for operations over the MCG.

Traffic helicopters

Airservices contacted the traffic helicopter operator about these activities. The operator flies as high as possible to minimise noise to residents and has zoom lenses to enable filming from 1500 feet. The minimum altitude over residential areas is 1000 feet, although the operator has a dispensation from CASA to fly lower if required. This is rare. The helicopter has been fitted with mufflers to minimise noise to residents. Sometimes air traffic control require the helicopter to fly below 1500 feet or to hover to remain out of the way of regular aircraft traffic to and from Melbourne Airport. Otherwise, hovering is avoided whenever possible. In the morning, traffic reporting activities are usually finished by 9.00 am and in the evening by 6.00 pm.

Yarra River helipads

Following complaints from residents affected by helicopters operating to and from the Yarra River helipads, Airservices worked with helicopter operators to encourage them to minimise noise. Operators agreed, wherever possible, to use their quieter helicopters, to restrict the times they use the helipads and to try to avoid overflight of noise-sensitive areas.

The Yarra River helipads are outside controlled airspace. The are which the helipads occupy is under the control of Parks Victoria.

More information about helicopter operations

Posted on

How runways are selected?

Weather, in particular wind speed and direction, is generally the main factor in determining which runways are in use at an airport, in which direction aircraft will take off and land and which flight paths are used.

At all times, the safe operation of aircraft will be the primary consideration.

Runway naming

Runways are named using a numbering system which reflects the runways’ orientation. The number, between 01 and 36, correlates to the degrees on a compass, for example:

  • A runway numbed 09 points east at 90 degrees
  • A runway numbered 27 points west at 270 degrees.

Some airports will have additional runways side-by-side, in this case the letters, left, right and even center are used to differentiate the different runways.

Runway use

Runways can be used in both directions and a runway will have a different name to refer to each end. In the above example the runway runs east-west, with runway 09 pointing east and 27 pointing west.

How can I find out more?

You can read more in our factsheet, available here.

Posted on

How is airspace used?

Each year we manage domestic and international air traffic operations for over 140 million passengers on more than four million aircraft movements in a region covering 11 per cent of the world’s surface. The following video shows what 24 hours of operations looks like:

Controlled and uncontrolled airspace

Airspace is designated as either:

  • Controlled airspace which is actively managed by air traffic controllers and is broken up into a number of different classes or classifications. To enter controlled airspace, an aircraft must first gain a clearance from air traffic control.
  • Uncontrolled airspace which requires no clearance (or supervision by air traffic control) to operate. The large majority of light aircraft and helicopters operate outside or underneath controlled airspace (for example, aircraft that operate at low levels over Sydney Harbour).

Terminal Airspace

Terminal airspace is the controlled airspace surrounding a major airport, generally within a 30–50 nautical miles (55–90 kilometres) radius. In the case of some major airports, this airspace extends from ground level up to 18,000 feet (approximately 6,000 metres).

As the distance from the airport increases, the lower boundary of this airspace rises in steps, enabling other airspace users (such as gliders and balloons) to operate outside terminal airspace without requiring an air traffic clearance.

Restricted Airspace & No fly zones

In restricted airspace, aircraft movements are restricted in accordance with certain specified permissions. Examples of restricted airspace include airspace around military installations and high density flying operations at an air show or other large public event.

Restricted airspace may be imposed by police for safety or security reasons in the vicinity of bushfires or major crime scenes. Decisions on restricted airspace are made by the Civil Aviation Safety Authority.

No-fly zones are similar to restricted airspace but are imposed and enforced by the military (usually the Royal Australian Air Force). No-fly zones will often be established around military exercises, heads of government meetings and major events such as the Olympic or Commonwealth Games. Airservices has no authority or control over no-fly zones.

Find out more

Read more about our operations in our Guide to our operations booklet.

Posted on

Investigation: Proposed night-time respite southern departure path

Airservices proposed a trial to change the flight path for some aircraft departing to the south off Runway 21 at night. The environmental assessment (based on noise modelling) indicated it would not deliver an overall noise improvement. To validate the modelled data used in the environmental assessment, in March and April 2016 Airservices conducted a six-week validation study. Noise monitors were installed at several points along the proposed flight path to obtain baseline noise readings, and then some aircraft were re-routed to use this flight path to collect actual noise level readings. This allowed a direct comparison between actual noise data collected and the modelling data that was used in the environmental assessment.

The study validated the modelling data used in the environmental assessment. As a result that flight path initiative will not be pursued further.

You can read the report here

Posted on

Investigation: Night time helicopter movements

In response to complainants raising concerns about helicopter movements during the curfew, Airservices investigated all helicopter movements to and from Adelaide Airport between 1 July and 30 September 2016. The investigation found that in each case these movements were emergency services helicopters which are permitted to use the airport during the curfew period.

The curfew applies only to aircraft arriving at or departing from Adelaide Airport. Aircraft travelling between other origins and destinations are permitted to fly over Adelaide during curfew hours.

More information about helicopter operations.

Posted on

Controlled and uncontrolled airspace

There are two types of airspace — controlled and uncontrolled.

Controlled airspace

Airservices air traffic controllers manage controlled airspace. To enter controlled airspace, an aircraft must first gain a clearance from air traffic control. In controlled airspace all aircraft must have continual radio contact with air traffic control and submit a flight plan detailing the route and height they will fly. Some emergency operations do not have to submit a flight plan, due to the urgency of their flights.

Uncontrolled airspace

All other airspace is uncontrolled. No clearance is required to operate in uncontrolled airspace and there is no supervision by air traffic control. Pilots operating in uncontrolled airspace must still comply with aviation regulations. However, they do not need to submit a flight plan and they may only have partial radio contact. The large majority of light aircraft and helicopters operate mostly in uncontrolled airspace.

Find out more

Learn more about classes of Australia airspace

Posted on

Seasonal weather patterns

Because aircraft must take off and land into the wind for safety reasons, the runway selected for use will be the one that allows “into-wind” operations. 

Wind patterns tend to be seasonal.  This means that at some times of the year a runway and its associated flight paths may receive more use than at other times of the year.

The following image outlines the seasonal wind patterns and how they vary around Australia.

Our fact sheet on Seasonal weather patterns explains this in more detail.

Posted on

How our system calculates flights over an area

The following video explains how our system calculates location-specific data used on this website:

The NFPMS

We source data directly from the Airservices Noise and Flight Path Monitoring System. The largest monitoring system in the world, combining data from air traffic control systems with a network of monitors deployed in local communities.

By using the location you provided when you entered the website, we extract data collected by this system and combine this with geographically relevant information, tailoring the site.

The grid

To be able to analyze the number of flights over your area, we have created a grid of identically sized, 1 kilometre by 1 kilometre squares. In total, the grid extends for 95 kilometres around each of the major airports in our coverage area. Initially this portal covers:

  • Adelaide
  • Brisbane
  • Cairns
  • Canberra
  • Gold Coast
  • Hobart
  • Melbourne
  • Perth
  • Sunshine Coast
  • Sydney

How we count the number of flights

We start by drawing a cone at the centre of each grid. Using the location that you provided when you entered the site, we determine the nearest cone to you.

Flights that pass through each cone are recorded and that
data is presented on this website.

To avoid underestimating the flights in each area and to fully cover all locations in our grid, we lower the cone 2,600 feet (800 metres) into the ground.

The cone extends up to 15,000 feet (4.5 kilometres) above local ground level and at the very top, the cone is over 30,000 feet (9.4 kilometres) wide.

Why we use a cone

We use a cone because research undertaken by the United Kingdom Civil Aviation Authority identified that a cone best aligns with how we determine if an aircraft has overflown a location or not.

The 48.5-degree angle of the cone was selected as it incorporates an evaluation of noise, in that if one aircraft flew directly above the observer, followed by a second aircraft off to the side along the 48.5 degree line, the second aircraft would be 3 decibels quieter than the first.