Step Change

Airbus also predicts that the number of domestic passengers at Australia’s capital city airports will double during this period. To cater for this growth Brisbane Airport will commission a new runway by 2020. Perth and Melbourne airports also plan to have new runways operational by 2021. A new airport at Badgerys Creek is expected to begin operation around 2025 to meet the traffic demands of the Sydney basin. The areas surrounding Perth, Brisbane, Melbourne and Sydney each contain a number of other civil and military airports. Air traffic operations at these major international airports are impacted by the operations at other airports in their vicinity.

To improve the capacity and efficiency of the ATM system, while reducing operating costs of users,

It is an opportunity to lower operational costs for airspace users.

Australia is aligning with a number of global initiatives. Airservices and Defence have recently signed a contract to commence work on the OneSky common civil-military ATM system (CMATS). This new system is expected to become fully operational in 2021 and will introduce new technology that provides the capability to enhance safety, capacity, environmental outcomes and efficiency.

Then there is the Metron Harmony ground delay program initiative that balances the number of aircraft demanding access to our airports and airspace against the capacity of the airport and ATM system to cater for them. The Harmony system draws upon a number of inputs including forecast weather, availability of infrastructure and aircraft traffic patterns to determine the traffic movement capacity of a runway up to 24 hours in advance. Airservices National Operations Centre (NOC) then uses this information to determine the number of aircraft that can access these airports at various times of the day. This system is a core element of air traffic flow management.

The cross-industry Airspace Capacity Enhancement (ACE) program, meanwhile, seeks to maximise runway utlisation at major Australian airports. The collaborative approach of airlines, major airports and Airservices working together has advanced a number of local and national initiatives that have enhanced airport capacity. On a location-by-location basis, ACE has developed specific procedures to minimise the aircraft runway occupancy time such as detailing standard aircraft speeds on initial and final approach. These common speeds have enabled greater consistency in the spacing of aircraft.

And Airport Collaborative Decision Making (A-CDM) is another cross-

It also creates a predictable arrival or departure sequence.

industry program being undertaken by airlines, major airports and Airservices. A-CDM links all stakeholders together at an airport with a common shared picture of ground operations enabling greater planning efficiencies and ultimately a more predictable operating environment.

Now the Future Airspace System (FAS) seeks to provide for greater airspace capacity and safety, while lowering operational and environmental costs.

“The FAS, in essence, is a major redesign of Australia’s airspace,” Greg Hood, Airservices’ executive general manager air traffic control, explains. “It is needed to incorporate the new airport infrastructure that will be introduced to accommodate the strong traffic growth, plus realise the capabilities offered by CMATS. This involves redesigning terminal and en route airspace to reflect new aircraft navigation systems, performance-based navigation and optimum climb and descent flight profiles. The airspace redesign needs to be consistent with world’s best practice adapted to the Australian environment. It is a large undertaking involving many stakeholders. Airspace changes will be delivered incrementally over the next 10 years. ” FAS seeks to standardise the service provided. When an aircraft departs from one terminal airport the goal is for the pilot and aircraft to experience the same seamless service, procedures and processes across all phases of flight from departure to arrival at the destination airport. Although a flight from a regional airport to a Class C airport will have some differences at each end, the experience across Australia should be consistent. The more harmonised and standardised airspace design becomes, the less burden is placed on all airspace users and ATC to manage variation and regional differences.

For Airservices, standardised procedures and airspace will improve operational efficiency and potentially enable generic licence endorsements for air traffic controllers.

The emergence of satellite-based navigation, improvements in aircraft avionics and enhancements to ATM systems are providing the opportunity to lower operational costs for airspace users. One of the major elements is through off air route operations (OARO). OARO replaces the need for aircraft to navigate along a fixed route determined by navigation aids located on the ground. Two forms of OARO are provided in Australia, Flex Tracks and User-Preferred Routes (UPRs).

Flex Tracks are air routes that are published daily between specific city pairs and are designed to take advantage of prevailing upper level winds. They are also often established to deconflict opposite direction traffic and avoid restricted airspace.

A UPR is a track generated by an aircraft operator, tailored for the specific aircraft type and operation. This process requires aircraft operators to consider all of the ATM constraints in order to generate a compliant flightplan. Unlike a Flex Track, each operator may be flying a completely different route. The route variability of UPRs creates considerable complexity for air traffic controllers in separating aircraft, as it moves away from a standard predictable airspace structure to a more service-orientated, dynamic environment. New technology is needed to help predict when the route of two or more aircraft will come into conflict. At present due to the complexity presented to air traffic controllers, UPRs have been limited to low volume airspace where the additional workload is manageable.

“CMATS functionality will include automated delegated conflict detection (ADCD) that will see conflict detection and resolution automated by software within the ATM system,” Hood notes. “In the meantime, Airservices is continuing to invest in conflict detection tools in order to increase the availabilityof UPRs. Thales is developing medium-term conflict detection (MTCD) for the existing TAAATS ATM system. It will provide a five minute look ahead alert to identify aircraft routes that will conflict. While air traffic controllers will still undertake the necessary actions to effect separation, MTCD provides an additional layer of safety. ” Since 2013 all aircraft operating at FL290 and above have been required to be fitted with ADS-B avionics. At FL290 this ADS-B technology provides surveillance over the entire area of continental Australia, enabling a greater use of OAROs.

“Our analysis shows that 99. 5 per cent of commercial jets operating at FL290 and above are ADS-B equipped,” Hood says.

“ADS-B surveillance enables air traffic controllers to monitor aircraft flying OARO and provide 5nm separation between aircraft. This surveillance information enables the ATM system to generate conflict and other safety alerts. ” The climb and descent profiles of aircraft are also undergoing significant change. Up to now aircraft departing from major airports can often undergo a number of turns and are held at intermediate levels before they get clear of conflicting arriving aircraft. Similarly, arriving aircraft need to join arrival patterns that can involve an interrupted descent and extended radar vectoring along routes to keep clear of departure paths. Maintaining intermediate levels and increased track miles increases aircraft operating costs.

FAS will use performance-based navigation (PBN) criteria to design arrival and departure routes. PBN enables aircraft to utilise accurate on-board navigation systems to determine position. Compared to the traditional ground-based navigation aids, the increased accuracy of PBNenables routes to be placed closer together while still maintaining route separation PBN also enables vertical restrictions to be built into arrival and departure procedures. This means that smaller airspace volumes need only be reserved for each procedure and it allows routes to be located closer together. PBN also provides the flexibility for routes to be designed to manoeuvre around high terrain and noise-sensitive areas.

Importantly, this enhanced ability to segregate routes enables greater opportunities for aircraft to fly their optimal climb and descent profiles.

For continuous descent operations the goal is to enable an aircraft to remain at cruise level for as long as possible, then undertake an uninterrupted descent to the final approach fix. The descent profile is determined by the aircraft’s flight management system, taking into account prevailing wind conditions and the route to be followed.

“The optimal climb or descent profile may be difficult to achieve on occasions due to factors such as traffic density or mix of aircraft,” Hood notes. “A fuel-efficient procedure, however, can be developed for an aircraft where constraints are minimised and an accurate vertical profile and route can be predicted and managed by the flight management system. ” The current Australian airspace model involves terminal airspace areas (TMAs) extending for 30nm around an airport. This TMA design is a throwback to the days when non-pressurised aircraft, operating at or below 10,000ft, would commence descent at 30nm from the destination. Air traffic control sectors and staffing are alsostill largely based on this outdated TMA model.

Modern high-level jet operations commonly commence descent as far out as 150nm from the airport. FAS involves extending the size of TMAs to incorporate this greater descent area. This greatly enlarged area is termed the extended manoeuvring area (EMA). In Australia, EMAs will be created around major capital city airports. Initially, EMAs will be created around Perth, Melbourne, Sydney and Brisbane. Routes for aircraft operating under PBN will be developed to optimise climb and descent paths.

Creation of EMAs also provides opportunities to make air traffic control delivery more efficient. Having the EMA encompass the area of descent and segregating arrival and departure paths will minimise coordination between air traffic controllers. Tightly contained PBN routes that are segregated will also reduce the number of occasions that air traffic controllers need to intervene to effect a separation. Reduced need for coordination and intervention provides the opportunity to increase the traffic handling capacity of air traffic controllers. It also creates a predictable arrival or departure sequence that will make full use of available runway and airspace capacity.

At other major airports including Adelaide, Cairns, Townsville and Darwin, the TMA concept will be retained. These airports do not have the traffic density of other capital airports or other airports located nearby. The radius of these TMAs will increase from 30nm to 50nm.

A fixed route structure, albeit defined with greater accuracy, will remain within EMAs and TMAs. This fixed route structure will be detailed in standard arrival (STAR) or standard instrument departures (SIDs). These STARS and SIDs detail the route foraircraft between the airport, through the EMA/TMA, and en route airspace. Entry and exit points for en route airspace will be defined.

Internationally, a number of new initiatives are emerging to increase airport and TMA airspace capacity. These initiatives include enabling optimal runway movements to take place in all weather conditions (eg, time-based separation) and in certain circumstances, allowing pilots to assume responsibility for separation from a preceding aircraft during arrival or departure.

“Airservices is closely watching initiatives taking place in Europe and the USA. In the next five years, we will be heavily committed to implementing CMATS. The amount of change we can effectively undertake, therefore, has to be closely managed,” Hood said.

“My view is that we will continue to monitor other international initiatives but not rush in. It is important, though, that the new EMA airspace design is in place by the time the new parallel runway at Brisbane is operational. ” En route airspace fills the space between the boundaries of the EMAs and TMAs to incorporate both fixed routes and OAROs. A fixed route structure will remain along the J curve and for short sectors, typically serving regional centres. The term J curve is used for the area that follows the eastern and southeastern seaboard of Australia from Cairns to Adelaide. This area incorporates the majority of traffic flows within Australia. Under the FAS, aircraft entering or leaving the J curve will join or leave the fixed route at published entry and exit points. It will also include duplicated fixed routes connecting high traffic city-pairs.

En route airspace outside the J curve will provide for flexible air routes and UPRs. It will also maintain some fixed route structures to cater for aircraft that are not equipped for OAROs. OAROs over continental Australia will be supported by surveillance by ADS-B ground stations. Outside continental Australia, surveillance is reliant on aircraft being equipped with ADS-C. Looking ahead, satellite-based ADS-B is expected to become available in 2017. This may provide an alternative surveillance source to ADS-C for oceanic traffic.

Currently between Airservices, Defence and CASA there is no efficient mechanism to efficiently coordinate structured changes to airspace. In practice, changes are managed on a local basis and the impact of these changes are generally not assessed from a network perspective. FAS is a concept designed to address this area by providing a coordinated plan for the modernisation of Australian airspace to meet Australia’s future civil and military requirements.

Airservices is the agency charged with the responsibility to develop the new airspace arrangements and route structures. It is also responsible for implementing the technologies to enable these new route systems. These routes, airspace and technologies, however, need to meet the operational requirements of users. A different approach is being adopted to engage the aviation community around FAS.

Hood explains: “Airservices, in the past, has unilaterally anticipated technological developments and operational requirements and then provided airspace users with what they believe they want. We typically engaged well with airlines but major airports had limited involvement in the decision-making process. Development of the FAS has provided the opportunity to adopt a truly collaborative approach among the various industry stakeholders. “The goal of this industry engagement is to become proactive in identifying and developing the airspace system, procedures and technologies to meet airspace user requirements. It ensures that airports are able to align their infrastructure and practices to agreed operational requirements. This approach moves away from the reactive methods that have taken place in the past. ” Industry engagement in the development of the Future Airspace System is being conducted through two forums, the Air Traffic Operations Executive Group (ATOEG) and the Australian Civil-Military ATM Committee (ACMAC).

ACMAC is the joint Airservices and military forum that focuses onharmonisation of the activities of the two agencies providing air traffic management services in Australia. It will be informed by, and monitor, the strategy.

The ATOEG consists of senior executives from major airlines and other industry stakeholders. Their representation will ensure that air traffic operational strategies are appropriately assessed and endorsed by major stakeholder organisations. Linking into the ATOEG are a number of ATO implementation monitoring groups which concentrate on the areas of airport operations, globally interoperable systems and data, optimum capacity and flexible flights and efficient flightpaths. These implementation monitoring groups will provide detailed scrutiny over new proposed initiatives.

“Having new initiatives supported by industry through the ATOEG makes it clear to Airservices what our priorities for operational and capital expenditure need to be,” Hood says.

“Approval of work programs by the ATOEG will be an important consideration in our planning process. In order for this partnership program to be successful, all parties will need to be mindful of the need to represent all industry stakeholders. For FAS to deliver its potential benefits it requires that all parties remain engaged and committed to the objective and vision. ” In practice much of the work will fall to Airservices to undertake, such as procedure design, but airlines and major airports will likely have a greater focus on planning future system requirements and approval of proposed changes. Redesign of the Brisbane EMA is intended to take place first followed by Melbourne, Perth and the Sydney basin. The Brisbane airspace redesign will take place before the new parallel runway is commissioned in 2020.

The future is not that far away.