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ADS-B Frequently Asked Questions

Questions ...

Answers ...

Q. What will be the scope of any ADS-B deployment?

The scope of any legislation requiring ADS-B and/or GNSS avionics in Australia has been under discussion for a number of years, and will ultimately be determined by the government. In 2007, the Aviation Policy Group ( which is made up by the heads of Airservices Australia, the Civil Aviation Safety Authority, the Royal Australian Air Force, and the Department of Infrastructure) released a Joint Consultation Paper on the transition to satellite technology for navigation and surveillance. The Government will use the feedback to the Joint Consultation Paper in any decisions made on ADS‑B and GNSS implementation.

A decision is expected to be made late in 2008.

 

Q. I’m a general aviation pilot. What will change for me?

Q. I’m a general aviation pilot. What will change for me?
All aircraft will benefit from an improvement in the safety of the Air Traffic management (ATM) system offered by ADS-B.
Airspace procedures designers are working on the assumption that, beyond mandatory carriage of ADS-B/GNSS avionics, for the great majority of GA and sports aviation pilots, very little if anything will change in their day-to-day flying activities. There have already been some changes to ATC phraseology and flight planning requirements to support ADS‑B implementation in Australia. No further changes are anticipated.

Airservices Australia has developed a computer based training module about ADS-B for general aviation pilots. This is available at http://www.airservicesaustralia.com/pilotcentre/projects/adsb/presentations.asp.

 

Q. Will my access to airspace be affected?

The proposed transition to satellite technology described in the Joint Consultation Paper, including broad requirements for carriage and use of ADS-B avionics was developed in part to facilitate greater access to airspace for more users, because most aircraft will be fitted with the equipment they need to operate in more airspace. Electronic “visibility” of aircraft will increase situational awareness, improving safety in any airspace design. In the event of a broad deployment of ADS-B, there are unlikely to be any loss of the gains for general aviation and sports aviation obtained through the NAS modernisation as a result of ADS-B deployment.

Note however that the Government is yet to determine what the full implementation of ADS‑B and GNSS in Australia will be.

 

Q. Will ADS-B improve safety?

Yes. An Air Traffic Management System supported by ADS-B technology will provide more accurate aircraft trajectory information for air traffic management, improve surveillance where required and offer pilots new safety functionalities that were previously unaffordable for GA. Pilot situational awareness will be increased, thereby further improving safety around Australia’s regional aerodromes. The introduction of ADS-B/GNSS avionics will accelerate the introduction of other advanced GNSS products to give pilots traffic and terrain information. If implemented outside the areas where there is enroute radar coverage today, considerable safety improvements are expected through more rapid and targeted search and rescue response, reduced collision risks around regional aerodromes, and reduced CFIT risks though facilitation of improved terrain awareness.

In addition, the proposed requirements for carriage of ADS-B/GNSS avionics fitment will ensure that all IFR aircraft have high-quality aviation-standard certified GNSS navigation equipment (certified to TSO-C146a). This will mean that IFR navigation will become more accurate and have higher availability/integrity with the introduction of ADS-B.

 

Q. How much will ADS-B cost me?

Maintaining the existing enroute surveillance and navigation networks (secondary surveillance radars, NDBs, VORs, etc) will be very expensive for Airservices Australia. If ADS-B based surveillance and GNSS only-means navigation can be deployed instead, the Australian Industry may be able to fund basic ADS-B/GNSS equipment for all affected aircraft with MTOW less than 5,700 kg, and still make considerable savings.

The Joint Consultation Paper included provision for cross industry funding to support ADS‑B installation in light aircraft. Access to the funding was proposed to be via a voucher system, with $15,000 vouchers available for operators of IFR aircraft to equip their aircraft with ADS‑B avionics and TSO‑146 or equivalent GNSS navigators, and $10,000 available for operators of VFR aircraft to equip their aircraft with ADS‑B avionics including TSO‑145 or equivalent GNSS engines. Base-model avionics are considered to be an ADS-B transmitter and GNSS engine for VFR aircraft; and an ADS-B transmitter and GNSS navigator for IFR aircraft. It will be possible for operators to purchase add-on ADS-B/GNSS avionics units – such as ADS-B receivers, traffic displays, moving map displays, etc – at their own cost. Maintenance costs for ADS-B equipment have been estimated at $150 every two years.

 

Q. Is ADS-B a new technology?

International ADS-B and GNSS experience has been building for many years. ADS-B using Mode S technology was used on helicopters in the Gulf of Mexico as far back as 1994. It represents a logical and relatively simple expansion of the Mode S technology that is the cornerstone of ATC radar and TCAS. Several thousand airframes worldwide (mostly airliners) are now transmitting ADS-B signals, and Airservices Australia has been conducting an ADS-B trial in Queensland’s Burnett Basin region since 2003. The Burnett Basin trials have afforded proof of concept opportunities for pilot and controller procedures, and have provided an opportunity for comparison of ADS-B and radar performance.

ICAO has taken the decision that Mode S 1090 MHz Extended Squitter technology is the appropriate ADS-B technology for the Asia Pacific region. The 1993 worldwide meeting of ICAO members (Air Navigation Conference 11) supported Mode S technology as the initial interoperable ADS-B link for international standardisation. The United States have chosen the same technology for air transport aircraft.

Both Airbus and Boeing are now including Mode S 1090 MHz ES as standard fitment on all new deliveries.

Currently trials or full implementation programs are underway in Australia, New Zealand, Canada, the United States, France, England and Iceland. This experience is being used to develop the pilot and ATC procedures that will be used in Australia.

 

Q. Isn’t ADS-B technology unproven?

Far from being a completely untried technology, international ADS-B experience has been building for some time. ADS-B using Mode S technology was used on helicopters in the Gulf of Mexico as far back as 1994. It represents a logical and relatively simple expansion of the Mode S technology that is the cornerstone of ATC radar and TCAS. Several thousand airframes worldwide (mostly airliners) are now transmitting ADS-B signals, and Airservices Australia has been conducting an ADS-B trial in Queensland’s Burnett Basin region since 2003. The Burnett Basin trials have afforded proof of concept opportunities for pilot and controller procedures, and have provided an opportunity for comparison of ADS-B and radar performance.

ICAO has taken the decision that Mode S 1090 MHz Extended Squitter technology is the appropriate ADS-B technology for the Asia Pacific region. The 1993 worldwide meeting of ICAO members (Air Navigation Conference 11) supported Mode S technology as the initial interoperable ADS-B link for international standardisation. The United States have chosen the same technology for air transport aircraft.

Both Airbus and Boeing are now including Mode S 1090 MHz ES as standard fitment on all new deliveries.

Currently trials are either underway or proposed in Australia, New Zealand, the United States, France, England and Iceland. This experience is being used to develop the pilot and ATC procedures that will be used in Australia. The FAA is also planning to build ADS-B into the US air traffic management system.

 

Q. Why is Australia considering Mode S 1090 MHz Extended Squitter technology? Aren’t the Americans using Universal Access Transceiver (UAT) technology?

There are a number of ADS-B link technologies, and steps are being taken to ensure that Australia does not adopt a unique solution. ICAO has taken the decision that Mode S 1090 MHz Extended Squitter (ES) technology is the appropriate ADS-B technology for international harmonisation, and the ICAO Asia Pacific Regional Planning and Implementation Group (APANPIRG) has endorsed it for regional implementation. An increasing number of aircraft operating into and within Australia today are already 1090 MHz ES equipped.

The FAA has proposed 1090 MHz ES for all aircraft that operate above 24,000 ft, and allowed a choice of 10909 MHz ES or UAT for aircraft that operate solely below 24,000 ft. Unfortunately the two systems use different frequencies and are not interoperable, and considerable investment in additional ground infrastructure to translate and re-broadcast UAT and ES signals is required in the United States to provide air-to-air visibility.

One of the nice features of UAT as deployed in Alaska is the ability to uplink traffic (TIS-B) and weather or NOTAMs (FIS-B). While other types of links such as 1090 MHz could be used to provide similar services, TIS-B services require that the aircraft receiving the uplink data is in the coverage of (and detected by) an ATC radar. If there is no radar coverage, TIS-B services are unavailable.

FIS-B services via ADS-B datalink are attractive, but delivery of such products can be achieved by a large number of links. In the USA several vendors offer FIS services using separate avionics from ADS-B avionics.

TIS/FIS services are not offered in Australia, although 1090 MHz ES data can be used for air-to-air traffic displays for aircraft fitted with ADS-B receivers, without any intervention by ATC. Importantly, it appears that 1090 MHz ES avionics for light aircraft will be significantly less expensive than UAT avionics which currently cost in the order of $US15,000.

While 1090 MHz ES is approved for global use, UAT is only approved for operations in lower airspace in the United States (including some oceanic airspace), Guam, Puerto Rico, American Samoa and the US Virgin Islands. ICAO standards already exist for 1090 MHz ES, but are still in the draft phase for UAT. There is very little support for alternative links; VHF Data Link (VDL) Mode 4 has the disadvantage of occupying channels in the VHF band that are already saturated in some parts of the world. Support of a mixed 1090 MHz ES and UAT environment is complex and expensive, and would suffer overall system performance limitations in the Australian environment.

 

Q. Why should Australia deploy ADS-B before anyone else?

Australia has huge areas in which there is no ATC surveillance. The advent of ADS-B allows some level of service to be provided for the first time at reasonable cost in locations where it is justified. In addition to this, many aircraft operating into and within Australia are already transmitting ADS-B signals. Since 2006, Airservices Australia’s deployment ADS-B surveillance above 30,000 ft across continental Australia, has taken advantage of these transmissions to provide radar-like safety nets and improved operational efficiency for equipped aircraft.

Much of Australia’s current infrastructure has been developed over a long period to support requirements that were in some cases established up to 40 years ago. This infrastructure has a limited capacity to support current and future performance requirements, and much of it is very close to end of life. Australia is faced with a unique opportunity to modernise our surveillance and navigation infrastructures. Considerable investment is required to replace existing systems, or the opportunity could be taken to expand ADS-B surveillance and make use of GNSS technology for navigation. There is unlikely to be a similar opportunity for modernisation until 2020 or later.

It should also be noted that a number of other states have already deployed ADS‑B (including France in La Reunion), will implement mandatory requirements before Australia (Canada in Hudson Bay), or plan implementations in the near future (including Europe in 2015, and our neighbours Papua New Guinea, Indonesia and Fiji before that).

 

Q. Won’t ADS-B implementation require more controllers?

There appears to be a misconception that Airservices Australia intends to use ADS-B to expand surveillance across the entire continent. While it is intended to take advantage of the lower cost of ADS-B ground stations to provide some surveillance services in selected high density traffic areas, the provision Australia-wide ATC surveillance has not been the reason for looking at widespread ADS-B avionics fitment.

The use of ADS-B by controllers is expected to reduce controller workload since ongoing management of pilot position reports will be reduced and ATC situational awareness increased. It is envisaged that in some airspace, the number of controllers may be reduced. A real benefit of expansion of ADS-B avionics carriage – beyond the coverage of existing enroute radars – will be the ability for air-to-air surveillance to provide enhanced situational awareness for all aircraft operations without any input from ATC, if aircraft elect to equip with ADS-B IN CDTI equipment (CDTI is Cockpit Display of Traffic Information).

 

Q. I own a glider. I don’t think I could power ADS-B avionics even if I wanted to. Will I be grounded?

It is recognised that it is not feasible to require ADS-B avionics to be fitted to aircraft that cannot power such equipment (although hand held SSR transponders with ADS-B capabilities and self contained battery packs are being manufactured in Europe, if there was a need for such equipment). As is the case for any legislation requiring equipment carriage, there are always some valid cases for exemption, and the proposed ADS-B legislation is no different. However, if fitted with light weight and low power ADS-B avionics, sport aircraft will be able to benefit from the improved safety enjoyed by other operators and will increase safety for all other users at aerodromes with a mixture of aircraft operations.

The 2007 Joint Consultation Paper explicitly stated that aircraft such as gliders would be exempt from requirements for ADS‑B avionics.

 

Q. What will Airservices Australia do with ADS-B data? Is ADS-B data going to be used for revenue raising for Airservices Australia and CASA?

There appears to be some concern among the general aviation and sports aviation communities that ADS-B data will somehow be used to raise revenue or for surreptitious surveillance of aircraft activities. While some agencies of the government will benefit from access to ADS-B data for search and rescue, surveillance, and enforcement, those agencies will have to follow the same legal process to obtain that data as they do today for access to radar data.

Airservices Australia does not currently use radar (or ADS-B data) for charging purposes. Charging information is derived from flight plans and manual input. In the future, Airservices Australia may use surveillance data (including ADS-B data) to improve the accuracy of charges calculations, but Airservices Australia only charges for services provided; and this will not change.

 

Q. I don’t want anyone knowing where or who I am. Can I just turn off my ADS-B avionics?

CASA airspace rules will determine where and when ADS-B systems must be operated or can be turned off. Aircraft with inoperative ADS-B avionics will downgrade system safety and security for all users. An advantage of being able to receive ADS-B data that includes aircraft call-sign (registration or flight number) is that initiation of communications (by either ATC or other aircraft) will be easier.

 

Q. Why are ADS-B and GNSS being connected? Aren’t they two separate technologies?

An aircraft equipped with ADS-B OUT avionics autonomously broadcasts its identity and its position derived from GNSS navigation equipment. This broadcast can be received by ground stations and presented to ATC, enabling radar-like surveillance of aircraft movements at significantly lower cost. The broadcast can also be received directly by other aircraft fitted with ADS-B receivers (ADS-B IN technology) and position of proximate traffic can be displayed in relation to own aircraft position on a cockpit display. While many larger aircraft can broadcast position using existing navigation equipment, smaller aircraft will require fitment with new high quality aviation GNSS equipment to provide their position.

For an aircraft operating under Instrument Flight Rules (IFR) that GNSS equipment could also be used for navigation, without recourse to ground-based radio navigation aids. This presents an opportunity to reduce the number of navigation aids required to support navigation, as well as reducing surveillance-related costs.

There is considerable synergy between the case for ADS-B OUT avionics and the case for GNSS avionics. The cost of combining ADS-B and GNSS activities is much less than the cost of doing them separately at different times. The merits or otherwise of combining GNSS and ADS-B in the Cross Industry Business Case have been debated at length at ASTRA forums, by diverse representatives of the Australian aviation industry. For some time Industry consensus has been that the two should be considered together.

 

Q. Why doesn’t Airservices Australia consider rationalising navigation aids and making GNSS navigators mandatory as a stand-alone project, rather than linking the navaids with the radars?

This has been considered. Requiring all IFR aircraft to carry TSO 146 GNSS navigators (which were approved for only means navigation in 2006) would enable Airservices Australia to reduce the number of NDBs and VORs to a backup network, designed to assist aircraft to land in the event of a catastrophic GNSS failure. Unfortunately, this proposition will still involve considerable expense for most operators (including airlines; most Australian airliners are not yet equipped with the required TSO 146 GNSS avionics), and will not significantly reduce Airservices Australia’s costs. This means that Airservices Australia is unlikely to be able to pass any savings on to its customers, which in turn means that GNSS navigators are unlikely to be subsidised in any way, thereby imposing a cost burden on GA.

 

Q. Why are the terminal area radars being replaced but not the enroute radars?

Australia’s terminal area and enroute radars were commissioned between 1991 and 1992. The radars are already experiencing predicted age-related increases in maintenance costs, and certain key components are becoming difficult to procure due to obsolescence. A primary operational requirement for terminal area radars is for the detection of Violation of Controlled Area (VCA) intrusions by aircraft that are either not transponder-equipped, or that have a non-functioning transponder (that is either off or failed). The detection of VCAs is imperative for the safety of airspace around Australia’s busy primary airports. The only commercially available and viable technology for this requirement for the foreseeable future is primary radar.

The enroute radars also need to be replaced, but Airservices Australia will forestall this using parts from the terminal area radars as they are decommissioned. This will extend the life of the enroute radars until about 2014, after which they will need to be replaced – with either new enroute radars or ADS-B.

 

Q. What add-on ADS-B products will be available and how will they work?

Moving Maps: A moving map could obtain high integrity aviation-approved GNSS data from the ADS-B GNSS box at the output connector. The moving map could include airport maps and terrain as well as waypoints. Low cost ADS-B avionics are expected to have a GNSS output.

Traffic Displays: ADS-B data can be use to display high-integrity traffic information, including call-sign, altitude and groundspeed. An ADS-B receiver would be required, with a connection to a display device. Typically, this would be the same device on which a moving map could be displayed. This could be anything from a hand-held PDA organiser to a sophisticated multifunction display.

 

Q. I’ve seen reference to ASTRA in connection with ADS-B. What is ASTRA?

ASTRA, the Australian Strategic Air Traffic Management Group, is Australia’s whole of industry Air Traffic Management (ATM) planning body. ASTRA includes representatives from airlines, airports, regional aviation, general aviation and various government organisations as well as pilots.

In 1999 Australia embarked on a world first initiative to develop an ATM strategic plan through collaboration between ATM stakeholders as equal partners. It recognised that future operating efficiencies and increased freedom of use of airspace would be achieved using systems requiring the cooperation of multiple aviation stakeholders. In 2000 a group of ATM stakeholders met with a goal of developing a plan that would ensure a safe, economic and efficient ATM system that accommodated demand, was globally interoperable, environmentally sustainable and satisfied national interest. The first edition of the Plan was published in 2001. Over time the composition and role of the stakeholder group has expanded and, now known as ASTRA, it is responsible for progressing and coordinating ATM planning and development within Australia.

The Plan sets the path for the future development of ATM in Australia over the next 15+ years and describes an ideal vision for the future. It highlights Australia’s commitment to the implementation of the International Civil Aviation Organization (ICAO) concept and global plan for ATM. Based on collaborative approach, the ATM Strategic Plan establishes a framework that enables Australia to keep at the forefront of CNS/ATM development and its associated benefits.

To support ASTRA there have been several working groups and implementation teams established to focus on implementation while still developing the plan. The Terms of Reference for each of these groups and more information about ASTRA can be found at http://astra.aero/index.aspx .

 

Q. I have ADS-B questions that aren’t answered here? Who do I contact?

This list of FAQs will be updated as more questions are received. Please send any questions to greg.dunstone@airservicesaustralia.com.

The Airservices Australia ADS-B web-site is a regularly updated source of information on current and future ADS-B deployment.

http://www.airservicesaustralia.com/pilotcentre/projects/adsb/default.asp.

 

Last Updated: April 2, 2008