AN EARLY definition of air traffic control was a service that ensured a safe, orderly and expeditious flow of traffic – a phrase that has stood the test of time, although, as aircraft performance and numbers increased, the original good intentions were often compromised or inhibited as well as problems with therandom effect of weather.
Radar alleviated some of the problems, but the relentless growth of air traffic led to a variety of palliatives to try and “ensure” the good intentions. Taxiway queues, long periods in the hold and delays in issuing clearances were often irritating but usually regarded as problems of success. Then fuel prices began to rise and even rocket, which made many of these “accepted” procedures unacceptable in financial terms.
To add to the equation, concern over climate change targeted many of these operationas to create even more pressure on air traffic services to reduce delays and introduce fuel saving, low noise levels and emission reducing procedures. Not an easy task and one that requires new thinking and new technologies. Many of the local regulatory authorities have been working along these lines for some time. Procedures are under constant review and revised to increase the use of more direct routings, sequencing efficiency and continuous descent approach techniques.
Typically, the Ireland/UK Functional Airspace Block, delivering the ENSURE project that began in December 2009, will remove air routes from Shannon Upper Airspace and allow direct routing and flight planning from entry point to exit into UK airspace. It is estimated that this initiative will deliver a number of benefits to airlines in 2010, including route distances saved of 2,2-million kilometres, fuel savings of 14 800 tonnes, CO2 savings of 46 800 tonnes and flight time savings of 195 500 minutes.
Unfortunately the desired result is often inhibited by current technology and the growing recognition that true change must involve all members of the industry working towards a common goal.
This was the message at a recent Naverus Performance Based Navigation (PBN) conference in Seattle. Delegates were told that PBN would enable major reductions in aircraft CO2 emissions, fuel burn and noise, if the aviation industry and the communities it served embraced the change together and reached agreement on implementation strategies. PBN will be able to unleash the full potential of current-generation aircraft to fly precisely- defined paths without relying on ground-based radio navigation signals.
Required Navigation Performance, (RNP) an enhanced mode of PBN, guarantees the aircraft does not stray from the path and enables additional navigational flexibility, such as the ability to custom tailor a curved path. This is an exciting prospect and one that relies upon modern application of satellitebased technology.
NEXTGEN
In the United States much of this promise lies in the introduction of technology currently under the banner of the Next Generation Air Transportation System or NexGen. This is the Federal Aviation Administration’s (FAA) plan to modernise the National Airspace System (NAS) up to 2025. Through NextGen, the FAA hopes to address the impact of air traffic growth by increasing NAS capacity and efficiency while simultaneously improving safety, reducing environmental impacts and increasing user access to the NAS. To achieve its NextGen goals, FAA is implementing these new Performance- Based Navigation (PBN) routes and procedures that leverage emerging technologies and aircraft navigation capabilities.
In simplest terms, Performance-Based Navigation comprises Area Navigation (RNAV) and Required Navigation Performance (RNP) and describes an aircraft’s ability to navigate using performance standards. RNP is RNAV with the addition of onboard performance monitoring and alerting. RNP operation monitors the navigation performance it achieves and informs the crew if the requirement is not met during an operation. RNAV and RNP permit more efficient design of airspace and procedures, which result in improved safety, access, capacity, predictability and operational efficiency. They also can reduce emissions and fuel consumption. These procedures offer increased predictability of operations, reduce controller and aircraft communications, reduce fuel burn with more continuous vertical descents, reduce miles flown in Terminal Radar Approach Control (TRACON) airspace and reduce interaction between dependent flows in multiplex airspace.
Last October, Naverus Inc. announced that it was now providing performance-based navigation services to ConocoPhillips Alaska, Inc., something that signals the unveiling of a complete set of PBN solutions for the business aviation market. Inevitably NexGen tends to focus attention on the United States. However, similar work is going on in Australia, Canada, Peru, Sweden, Panama and New Zealand, while Boeing and Airbus are introducing initiatives to provide advanced PBN capabilities in their aircraft. Although this indicates the truly international scale of innovation, it will inevitably produce some problems.
Photo: Brain McNair
ERAM
Recently the FAA began a test of a new computer system at Salt Lake Centre. Things did not go exactly according to plan. Although the system held its own during light traffic on the overnight shift, it failed when traffic volume picked up later.
Called En Route Automation Modernisation (ERAM), the system is intended to offer greater flexibility, a better system for controllers and the arrival of a new “brain” for the National Airspace System that will form a an important part of the FAA’s Next Generation Air Transportation System. Unfortunately, the backup system also caused problems of its own. It is a story with something of a moral and controllers are suggesting that these problems could have been averted if the FAA had included the US National Air Traffic Controllers Association (NATCA) in this process and worked with the union to formulate a plan for training and contingencies. At all levels this new technology will require the goodwill and cooperation of all concerned to reduce the complexity to practical operation.
AIRSPACE REDESIGN
Although much is being made of the green credentials of these emerging systems, there is likely to be a process of education for many people on the ground. There will inevitably be a degree of airspace redesign, flight paths will be repositioned and aircraft will fly over areas where they have not flown before, always a sensitive issue. It will be important not to compromise the benefits of the system in response to “local” political pressure.
Technology seems to be progressing at a pace and there are benefits in combining ADSB and PBN implementation programmes, allowing simultaneous upgrades of both the surveillance and navigation systems from legacy, ground based technologies to new and more dynamic satellite-based technologies. Recently, the Civil Aviation Authority of Singapore (CAAS) and COMSOFT signed site acceptance test certificates for ADS-B receivers plus an ADS-B processing system, making the system ready to enter operational service.
In December 2008 the Singaporean air navigation service provider, CAAS, contracted COMSOFT with the deployment of its ADS-B sensors and a redundant data processor for sharing and distributing ADS-B data, plus an additional development and evaluation system. In addition, QCMS, a control and monitoring platform with enhanced statistic and evaluation features, was implemented. It allows the management of up to 64 ground stations. The new installation was further complemented with the advanced network management system CNMS, as specified by CAAS. As these new technologies come on line they are stitched together in a global communications web. EUROCONTROL has signed a contract with SITA to launch PENS, a pan-European communications network service that will allow all air navigation service providers to exchange voice and data communications in a seamless and integrated manner.
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