The Airspace Change Organising Group (ACOG) was established in 2019 at the request of the Department for Transport (DfT) and Civil Aviation Authority (CAA), to coordinate the delivery of key aspects of the Government’s Airspace Modernisation Strategy, namely the national programme of airspace change amongst major UK airports.

Operating as a fully independent organisation overseen by the CAA and DFT, ACOG is made up of airspace change programme and communications specialists.

The requirement for ACOG as defined in the AMS is to coordinate the delivery of two major national airspace change programmes known as Future Airspace Implementation South (FASI-S) and Future Airspace Implementation North (FASI-N).

  • FASI-S is a complete redesign of the existing airspace structure in Southern England
  • FASI-N is a programme with a similar scope covering the airspace in Northern England and Scotland.

ACOG may also take responsibility for coordinating other AMS initiatives related to airspace change if CAA and DfT consider it is appropriate.

Our Objectives

ACOG’s core objectives are to:

  1. Lead: Lead the airports and NATS En-Route PLC (NERL)in the creation of credible and implementable Masterplans for FASI-S and FASI-N.
  2. Coordinate: Coordinate analysis with stakeholders to identify and understand the dependencies created by overlapping airspace changes.
  3. Integrate: Facilitate between stakeholders to strike efficient compromises and trade-offs that are needed to integrate the overall design.
  4. Communicate: Build a broad base of support for the airspace changes and join-up the industry’s approach to consultations and engagement.
  5. Demonstrate the Benefits: Demonstrate the collective impacts of the airspace changes and identify opportunities for all stakeholders share in the benefits.

Our Work - The Masterplan

The FASI-S and FASI-N programmes are made up of several linked airspace change proposals (ACPs) that are sponsored by the airports in each region and NATS, En-route Plc (NERL).

One of ACOG’s most important roles in coordinating airspace change is to draw together these many co-dependent strands of work into an overall Masterplan.

ACOG, in collaboration with NERL and the airports, will deliver a Masterplan that provides detailed information on the airspace design options under development, the potential areas of overlap between individual ACPs and the compromises and trade-offs that may need to be made to integrate them effectively.


Air Navigation Service Providers (ANSPs) including the NERL team that are tasked with redesigning the UK’s medium level airspace network above 7000ft. and the European ANSPs that border our airspace.

Airports that are modernising and upgrading their arrival and departure routes below 7000ft. and must ensure that they are aligned with neighbouring airports and connect efficiently with the network above.

Commercial Air Transport, General Aviation and Military users that operate in the airspace and may need to adopt new technologies and procedures as part of the FASI-S and FASI-N programmes.

New airspace user groups like drones and commercial space flights that are expected to demand greater access to the airspace in the future and will need to integrate with conventional users safely and efficiently.

Passengers, consumers and companies that rely on air transport for leisure and business and convert aviation products and services into a valuable driver for economic growth and global connectivity.

Interest groups, local communities and their elected representatives that are concerned about the external impacts of airspace modernisation, especially aircraft noise, emissions and the effects on local air quality.

Our Approach

ACOG will conduct its work in a positive, constructive and successful programme environment that supports all stakeholders that are participating in FASI-S and FASI -N or affected by the programmes' outputs. To guide the way ACOG work, the organisation has adopted three core principles:

  1. Objective and impartial
  2. Open and transparent
  3. Disciplined and rigorous

Find out more about the airspace change programme