Quicker, cleaner, quieter.
We’re making changes to the way our airspace is structured, to make our journeys quicker, cleaner and quieter.
More than 2.6 million aircraft fly through UK airspace every year, carrying over 300 million passengers all over the world. But it’s not just commercial aircraft that fly through our skies, there are military aircraft, private pilots, leisure flyers, drones and many others too — and everyone who wants to be there, has a right to be.
To meet those challenges, we're undertaking a major programme of work to modernise the way our airspace is structured and transform the technology our Controllers use to manage air traffic.
Government policy since 2018
The UK’s airspace is some of the most complex in the world, with its design dating back to the 1950s for aircraft which have long since stopped flying. The need to modernise it has now been recognised by the UK Government who tasked the Civil Aviation Authority (CAA) to co-ordinate how it happens.
The CAA’s Airspace Modernisation Strategy sets out the initiatives that the UK industry will deliver to achieve the Government’s policies. NATS has a central role to play, as does the Government, airports, airlines and the many others who use our airspace.
Modernising airspace, which means both route design and new tools and technologies, will make air traffic management more efficient, helping reduce the impact air traffic has on local communities and the environment, and supporting future growth. Find out more in our video below:
Enabling more precise and efficient flying
At the heart of the Airspace Modernisation Strategy is an airspace redesign programme to ‘systemise’ our airspace. This means creating a structured route network where aircraft follow defined routes between their departing airport and a point of exit from UK airspace, or from the point of entry in UK airspace to their arrival airport.
Systemised airspace will enable more efficient flight profiles and reduce the number of tactical interventions Air Traffic Controllers need to make.
Performance Based Navigation (PBN) and the Airspace Change Organising Group (ACOG) are key to modernising airspace:
PBN is a very accurate way of flying aircraft which uses satellite technology to allow aircraft to fly routes with more precision and consistency.
Previous generations of aircraft couldn’t fly as precisely as they can today, which meant navigating the skies using ground-based beacons and routes having a wide envelope of airspace surrounding them.
In the future, we will be able to create new, more closely spaced routes which will reduce vectoring and which can be alternated on an agreed basis to provide noise respite for communities below.
PBN can bring an end to stacking as we know it today. Instead, we’ll be able to using new concepts such as Point Merge and enable more continuous climbs and descents. While these aren’t new concepts — they’ve been used for decades — continuous climbs and descents are not always achievable in the airspace around busy airports.
Changing how we manage arriving aircraft will improve procedures for departing traffic which will no longer need to level-off to safely pass underneath the stacks. In the future, aircraft will more quickly reach altitudes where they are more efficient, and this will make it easier to manage the impact of noise on people who live near airports.
NATS is responsible for modernising the higher-level route network (what we call ‘en-route’), and airports are responsible for their low-level departure and arrival routes. In order to coordinate the changes required, an independent body has been set up — ACOG. Find out more about ACOG here.
To change airspace, we follow a process set out by the CAA called CAP1616, which provides guidance on when consultation is required with people who may be affected, whether they are airspace users or the wider public. For more information about specific airspace changes and to respond to open consultations visit our consultations section.
Removing stacks and reducing time to land
Over the past few years we’ve been investigating ways to reduce the time spent by aircraft waiting to land close to airports at low levels. PBN will further enhance these concepts as well as ending stacking as we know it today.
Here are some of the concepts we’ve been working on:
Designed to help Heathrow determine measures to balance forecast demand with capacity for up to 180 days in the future. Based on the local weather forecast, matching airport weather scenarios that have a defined effect on available capacity are selected. Together with user input on the expected infrastructure availability and operation mode, DCB calculates an effective capacity profile.
DCB is part of a SESAR concept developed to improve airport participation in the collaborative decision-making process between the Eurocontrol network manager and the Air Navigation Service Provider (ANSP).
Even with the most efficient ways of managing final approach, we can’t effectively manage arrival flows without working with other Air Navigation Service Providers (ANSPs).
Cross-border queue management makes it possible to work with neighbouring ANSPs like France and Maastricht Upper Airspace Centre to slow aircraft down up to 550 nautical miles from landing. This better manages the flow of aircraft into UK airspace by absorbing delays en-route.
The approach is already fully operational at Heathrow Airport and at Gatwick Airport.
When there are strong headwinds, aircraft ground speed slows, which means that using distance to separate aircraft on final approach reduces the landing rate. This causes delay. TBS dynamically adjusts separation distances using time, rather than distance, to keep landing rates consistent in strong headwinds. TBS forms part of a product developed by NATS and Leidos, known as Intelligent Approach. It was first introduced at Heathrow in 2015.
Following the success of TBS, NATS and Heathrow further developed the system for higher efficiency. Known as eTBS, the new system uses the latest European Wake Vortex Reclassification (RECAT-EU) for arrivals and departures.
eTBS provides Air Traffic Controllers with separation indications to the runway based on aircraft weight. This is supported by an Optimised Runway Delivery tool, which models the compression between aircraft pairs as they slow down to their landing speed.
The tools also provide controllers with runway occupancy indications for pairs of arriving aircraft when that is more limiting than wake separation.
Point Merge is a system by which the aircraft queuing to land fly an extended flight path around an arc instead of holding in circles. Aircraft fly along the arc until the next slot in the landing sequence is free. These arcs are generally higher than the stacks we currently use today. Point Merge was introduced at London City Airport in 2016 and is in operation at more than 25 airports worldwide.
Sharing for civil and military needs
Collaborating closely with partners and stakeholders we will be able to make optimal use of airspace working flexibility to meet different needs.
Access to airspace is critical for the UK’s security. We work closely with our counterparts in the military, with military and civilian Controllers sitting side by side in the operation to ensure that when required military jets can get in the air without as little disruption to civil air traffic as possible.
In the UK,there are sections of airspace the military use to train — commonly known as danger areas.
When the military are using it, passenger aircraft are not allowed in, but a cooperative approach (sharing tools, data and operational and technical processes) means that once the military is no longer using the airspace, they hand it back to civilian Controllers.
This means we can provide more efficient management of airspace, often reducing the distance an aircraft needs to fly.
When aircraft fly through European airspace, they’ve always had to fly in accordance with the airspace structure whichever country they are flying over. This often means flying further than necessary.
Free Route Airspace allows aircraft to fly the route they want between a defined entry and exit point rather than using these established routes. This allows airlines to fly a fully optimised flight path based on factors like weather and windspeed and will improve efficiency and reduce flight time, fuel burn and emissions.
Replacing radar tracking with satelitte surveillance
Radar doesn’t extend across oceans, so oceanic traffic has always had to be managed using a satellite-based messaging system which delivered position reports approximately every 14 minutes. But that changed in 2019, with the use of satellite-based surveillance.
In 2019, NATS, alongside NAV CANADA, introduced an advanced form of satellite-based surveillance which allows us to track aircraft over the North Atlantic almost in real-time. The technology means we can reduce separation between aircraft and remove the fixed speeds which have always been in place over the ocean.
Discover more about our oceanic operation and how we introduced space-based ADS-B across the North Atlantic or watch the video below for an introduction:
Increasing flexibility, safety, efficiency and resilience
Some of the equipment our Controllers use today has reached its ‘end of life’. That doesn’t mean it is unsafe; for many years we have sustained our existing systems and successfully extended their lifespan. But it’s not feasible to keep doing that.
Over the next five years we will be investing nearly £750m to replace our existing legacy systems with a modern and more capable system which is more familiar to the tablets and laptops we use every day, tailored for the operational environment with tools that support our controllers.
Our air traffic management systems currently operate on a single integrated infrastructure. This infrastructure must operate in complete harmony with our international neighbours without interruption day in, day out. But that is becoming increasingly difficult as it reaches its end of life.
Our future air traffic management system will introduce new flight data processing capabilities supported by modern Controller tools and a new Controller work station. It will strengthen safety even further, increase efficiency, and reduce the environmental impact of flights through more advanced and upfront detailed planning of flight trajectories. It will also further enhance interoperability between control centres in Europe, allowing us to share these detailed trajectories so that we can optimise aircraft trajectories across borders.
The development of that system is being done collaboratively with Air Navigation Service Providers (ANSPs) from across Europe as part of the iTEC system. This will introduce a common air traffic management system across multiple European ANSPs, responsible for more than 1/3 of flights across Europe, helping to meet the growing demand for air travel in Europe in a safe and efficient way.
We are coupling the core iTEC software with the highly advanced toolset, known as FourSight, which is already deployed by NATS in parts of UK airspace. FourSight gives the Air Traffic Controller unparalleled predictive capabilities to identify trajectory conflicts up to 18 minutes in advance, further improving safety, efficiency and capacity of the operation.
The future system will introduce 4D trajectory flight plan management which, supported by PBN, will enable smarter and more efficient flight plan data transmission.
When an aircraft needs to be re-routed, this information will be inputted into FourSight and the iTEC system will automatically identify a new routing. This will reduce the manual workload for Controllers and transform the way we manage our skies.
The introduction of our future workspace began with ExCDS - the automation of flight data management information. ExCDS has replaced paper strips and provides our Controllers with a more automated, touch-screen system.
By automating some processes, the tool reduces the need for manual coordination between controllers working in different positions. This increased electronic coordination is essential to help Controllers manage the ever-increasing demands on the UK’s skies.
The Airspace Capacity Management team are part of our everyday operation and are responsible for flow management, forecasting capacity and air traffic demand. We are currently developing a system (called iACM) with our partner Indra which will be used by the Airspace Capacity Management Team and will provide enhanced ability to predict traffic, create traffic management plans and support tactical decisions in the Operations Room.
iACM will use iTEC data and will be compatible with Free Route Airspace in the future, using the latest iTEC trajectory as well as external data sources. Giving support to the Airspace Capacity Management (ACM) team, it will allow the forecast of capacity and demand for chosen days and give a more strategic environment, for example being able to run ‘what if?’ scenarios.
SWIM is a global aviation standards-based concept that will improve how information is shared and managed. All ATM information, including aeronautical, flight, aerodrome, meteorological, air traffic flow, and surveillance will be available with the right quality to the right person, system or process at the right time.
What Next? R&D in ATM
Benefiting airspace users and the environment
From early uses of satellite-based aircraft tracking to the introduction of iFACTS, an innovative set of tools to help controllers safely manage growing volumes of traffic, we are committed to developing and implementing innovative solutions that deliver benefits to our customers now and into the future.
We are a proud member of SESAR (the Single European Sky ATM Research programme) and are committed to working with partners to improve the service we offer our customers and help deliver the vision of a Single European Sky.