Transforming the Skies: Systemisation

Looking up at the sky, the airspace appears as one large expanse, occasionally dotted with aircraft — from commercial jets to military planes, general aviation and drones. Unlike motorway networks, there are no physical markers to define boundaries, no visible lines to indicate altitude, and no signposts showing where aircraft can or cannot fly. Yet, just as roads are governed by rules to keep journeys safe, the sky is managed through a complex framework that determines where, when and how different aircraft can operate. These rules exist to keep the skies safe for all airspace users.

Systemisation will become a defining feature of how aircraft navigate the skies, bringing greater predictability, improved efficiency and better use of the UK’s busy airspace

Many of the operational procedures used across UK airspace were developed in the 1950s, at the start of the jet age. Fast forward to today, and aviation has changed significantly, increasing from an average of 200,000 commercial flights per year in the ‘50s, to 2.5m today. Aircraft are now far more technologically advanced, traffic levels are higher and expectations around efficiency, noise and emissions are now in sharp focus. To help address all these competing demands, a major programme is underway to modernise how UK airspace is designed and operated, enshrined in Government policy in 2018.

Enabling change

Key to this transformation is the adoption of Performance Based Navigation (PBN). PBN moves aviation away from fixed routes based on ground beacons and instead allows aircraft to follow precise, flexible paths using modern navigation technology, supported by ground-based systems. This allows aircraft to fly with far greater accuracy than previous beacon-based methods.

This accuracy underpins the new approach to designing both upper and lower airspace.

In upper airspace (typically above 24,500 feet), PBN enables the transition to Free Route Airspace, removing archaic route structures and allowing airlines the freedom to plot an optimised route through a large section of airspace, reducing the distance aircraft fly and so enabling lower carbon emissions.

A new order for the skies

At lower altitudes, where the airspace is busier, PBN is a crucial enabler of systemisation. Systemisation introduces a network of pre‑defined, structured flight paths through the UK’s busiest airspace. This precision allows aircraft to follow consistent routes, with smoother climbs and descents, more predictable traffic flows and more efficient use of limited airspace. In turn, this increases capacity by enabling aircraft to fly safely closer together and reduces the need for as many instructions from air traffic controllers. With fewer course changes and more predictable routing, aircraft can remain on optimal flight profiles for time and fuel savings.

Systemisation has already been implemented across a third of the UK’s airspace through the 2023 West Airspace Deployment over Wales and Southwest England – the first major systemised network between 7,000 and 24,500 feet.

It has set the template for the rest of the UK, enabling more than 150,000 nautical miles of flying to be saved each year, a cumulative reduction of around two hours of flying time per day, and over 12,000 tonnes of CO₂ savings – equivalent to the emissions of approximately 3,500 homes.

These changes mark a new era in aviation. As additional deployments roll out across the country, systemisation will become a defining feature of how aircraft navigate the skies, bringing greater predictability, improved efficiency and better use of the UK’s busy airspace. Modernising airspace is a long‑term national endeavour, but we can already see what’s possible: greater resilience, fewer emissions and a network ready to meet the needs of tomorrow’s aviation industry.