Airservices is Australia's air navigation service provider - we provide air traffic control, aviation rescue and fire fighting and air navigation services.

Airspace infringement

An airspace infringement (AI) is the unauthorised entry of an aircraft into airspace where a clearance is required, or to which entry is prohibited.

In an AI, there is the potential for your aircraft to operate in unsafe proximity to other aircraft. An AI may also increase air traffic control (ATC) and pilot workload and result in delays to other aircraft.

Airservices has developed fact sheets explaining using GNSS as a VFR navigation tool and safe operations around controlled and restricted airspace.

aircraft in sky

Pre-flight preparation

Thorough pre-flight preparation is a good defence against an airspace infringement. By solving potential problems on the ground, the likelihood of an airspace infringement is reduced.

Ensure you have current airspace charts

Make sure that you have current charts to cover your entire operation. Consider Control Area (CTA) steps and restricted areas along and around your planned route.

Charts can be purchased from the Airservices online store or from one of our resellers.

Descriptions of the various charts available for your operation are available on the Document and Chart Descriptions page.

Thoroughly familiarise yourself with local airspace and other aeronautical issues

Use your charts to study your planned route, and any possible diversions that may occur.

The Civil Aviation Safety Authority (CASA) provides a number of good reference materials to assist in pre-flight planning:

NOTAM Brief

Briefing of NOTAM, restricted areas and weather is available through the NAIPS Internet Service (NIS).

NIS includes an easy to read display of current restricted area status. (Please note that this tool only shows the status of restricted areas: military CTR/CTA is not included.)

Airservices has developed short videos explaining how to access and use the restricted area briefing page and how to access meteorological and NOTAM information for flight planning.

Consider the navigation tolerances that apply to your proposed route and level

When operating as a VFR pilot in Class G or E airspace, you must apply appropriate tolerances to your flight path to ensure that controlled airspace, or restricted areas, are not infringed.

Submit a flight notification prior to all flights

Regardless of whether or not you intend to enter controlled airspace during your flight, submitting a flight notification prior to your flight will speed up the availability of an airways clearance and the provision of assistance by ATC if you need it. For example, if you are intending to remain outside of controlled airspace, but then need to divert around weather and enter controlled airspace, it is a lot easier for ATC and you if you have already submitted a flight notification than it is to submit one via radio.

In-flight

Navigation
Always accurately know your position relative to the controlled airspace (CTA) steps.

Verify your position and the status of restricted areas in your vicinity if you arrive well ahead of, or after your anticipated time of arrival at a waypoint.

If in doubt, ask for navigation assistance from ATC (if you’ve got a flight notification submitted, this will be a lot quicker and easier).

It is better to have definitely passed a CTA step by a couple of miles before commencing climb than hugging the CTA steps and causing uncertainty to the controllers monitoring that airspace. Similarly, make sure you set up and fly your descent profile to arrive underneath any CTA steps well before the step boundary.

Avionics

Transponder
Ensure your transponder is serviceable before you fly.

Set your transponder to ON/ALT. If a specific code has not been given to you by ATC, set code 1200 in Class E or G airspace and code 3000 in Class D airspace (for VFR flights). Operating your transponder will make your aircraft and altitude visible to ATC, allow air traffic controllers to receive conflict alerts involving your aircraft, and allow larger aircraft to receive Airborne Collision Avoidance System (ACAS) advisories. Additional guidance on transponder codes and requirements is available in AIP ENR 1.6, 7.

Make sure you know how to operate the IDENT (sometimes SPI) function of your transponder. However, do not operate it unless directed to do so by ATC.

Global Navigation Satellite System (GNSS)
GNSS can only be used as the primary means of navigation if the system installed has been approved by CASA and you operate the system in compliance with this approval. If you don’t meet these requirements, your GNSS can only be a secondary navigation reference.

Be aware that CTA steps may be based on various references including the aerodrome distance measuring equipment (DME), the aerodrome reference point (ARP) or runway threshold. On the visual terminal chart (VTC), the steps will refer to the datum used (for example, 30 DME, 7 NM ARP, 8 NM FM THR RWY 01). If using GNSS to remain clear of CTA, ensure you are using the correct reference point.

Where surveillance (radar, wide area multilateration (WAM) or ADS-B) is available, controllers normally monitor aircraft as they approach CTA steps to anticipate potential airspace infringements. If you are flying toward a CTA step with the intention of turning to parallel the step at the last moment, this will cause concern to the controller as they may anticipate that you will continue on the same track. A better technique would be to start your turn well before the CTA step. Also, if the controller is aware of your intentions, through your communication or an active flight plan this will reduce some of their concern.

Radio use
Actively monitor the appropriate area radio frequency whenever possible and listen for transmissions that include your callsign, or that are directed to unidentified aircraft in your area. ATC may direct calls to you based upon your position, altitude or heading. Speak up if you think a transmission may have been directed to you.

Air traffic control

Controllers are there to help you. It is much better to ask Air Traffic Control (ATC) for help than to have an airspace infringement.

‘Flight Following’ is an ongoing Surveillance Information Service (SIS) available to VFR flights in Class E or G airspace. This service is provided to improve situational awareness and assist pilots in avoiding collisions with other aircraft. It is available on request, but always subject to ATC workload.

Remember: ask ATC for help if you are in doubt about anything!

Requesting clearance
You should request a clearance at least five minutes before reaching the CTA step. Have an alternative plan and a suitable decision point if you do not receive clearance, or are unable to call prior to the point you would enter controlled airspace.

Having a flight plan already submitted greatly increases the chances of getting a clearance, as taking flight details over the air is time consuming and increases controller workload.

Airspace infringement hotspots

Generally, airspace infringements do not occur at random locations. They frequently occur in the same areas and these are known as ‘hot spots’.

Sometimes these ‘hot spots’ are in critical locations, where an airspace infringement can interfere with the processing of traffic in controlled airspace.

Below are links to diagrams that show the location of the airspace infringement hot spots in the major basins. These hot spot diagrams also provide advice on what you can do to avoid having an airspace infringement in these locations.

The Department of Defence has provided the following diagrams showing the location of airspace infringement hot spots in East Sale and tips on avoiding them.

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