Proposed Criteria for Assessing and Accepting the Airspace Change Masterplan

Closed 26 Jun 2020

Opened 27 Feb 2020

Feedback updated 6 Sep 2021

We asked

The Department for Transport and CAA commissioned the airspace change masterplan from the Airspace Change Organising Group (ACOG) by. To ensure the masterplan is consistent with government policy and CAA statutory airspace functions, the CAA must ‘accept’ it into our Airspace Modernisation Strategy. 

The CAA’s engagement exercise published in CAP 1887 set out draft criteria for the CAA’s decision whether to accept the masterplan into the Airspace Modernisation Strategy – based on assessment by the CAA and Department for Transport of information provided by ACOG to determine whether the commission for the masterplan is being met, and the Government’s policy objectives are being delivered.

The engagement exercise was to give us the opportunity to strengthen our proposed criteria and take feedback on whether we were asking the right questions of ACOG as it developed iterations of the masterplan.

You said

We had 98 responses in total which we have published where we had permission to do so. Of those,

    • 34 responses were from members of the General Aviation community
    • 25 responses were from residents affected by aviation or local organisations such as community action groups
    • 12 responses were from the commercial aviation industry
    • eight responses were from a national or international representative organisation such as a trade association
    • seven responses were from a central or local government body, or from an elected political representative such as a councillor or MP
    • the remainder of responses were from a variety of organisations or individuals.

We asked four questions, all of which allowed a free-text response.

Two of the four questions included a multiple-choice answer format, where, of the 98 responses:

    • 44 responses thought that significant modifications to the acceptance criteria were needed; 33 responses said that the criteria were about right (19) or that only minor modifications were needed (14).
    • 61 responses thought that there were examples where further policy may be required to guide trade-off decisions in the masterplan and 10 thought there were not.

From our analysis of free-text responses we identified various themes across the four questions, which we arranged under 10 headings as follows:

    • Consultation or acceptance criteria not easy to understand
    • Proposed approach for accepting the masterplan
    • Negative comments about the CAA, government policy or ACOG’s impartiality
    • Masterplan acceptance criteria and airspace modernisation in the light of changed circumstances
    • Design standards that inform the masterplan
    • Envisaged engagement on masterplan inadequate or too much
    • Trade-offs – clarity and stakeholder input
    • Reducing environmental impacts should take precedence over growth
    • Concern about the extent of controlled airspace and/or detriment to General Aviation
    • Concern about airspace access or use by drones and spacecraft.

CAP 2157 explains these responses in more detail.

We did

We have published the criteria that must be met for acceptance as CAP 2156a Airspace Change Masterplan – CAA acceptance criteria and CAP 2156b Airspace Change Masterplan – assessment framework. In addition, we are publishing CAP 2156c which explains how you can give your input to masterplan development.

The table below summarises the changes we made to the acceptance criteria the originally proposed in CAP 1887.




The acceptance criteria have been amended to reflect that ACOG has now been commissioned to produce a masterplan covering the UK and not just southern England, thus encompassing the FASI-South and FASI-North programmes (FASI meaning Future Airspace Strategy Implementation) redesigning the existing airspace structure.

Clarity of document

For greater clarity we have published the criteria for accepting the masterplan as CAP 2156a Airspace change masterplan – CAA acceptance criteria and the assessment framework as CAP 2156b Airspace change masterplan – assessment framework. By assessment framework we mean the legal and policy considerations, and the process that the co-sponsors will follow (1) to assess ACOG’s progress with developing the airspace change masterplan iterations and (2) to confirm that these are delivering what the co-sponsors commissioned. We have introduced diagrams to illustrate the masterplan development process more succinctly, and also how it relates to the CAP 1616 process that sponsors of the airspace change proposals making up the masterplan must also follow. We have published a short guide, CAP 2156c Airspace change masterplan – future opportunities to express views, explaining the opportunities that stakeholders have for engagement with ACOG about the masterplan and sponsors about airspace change proposals.

Plain English

We have used plain English as far as we can for the acceptance criteria and explained any unavoidable technical terms. We have specified that ACOG’s engagement material must include a simple, clear and non-technical version in plain English, to include cumulative impacts, and a clear explanation of the expected benefits and programme timeline.


We are considering with ACOG and the Department for Transport how best to publish all the information associated with the development of the masterplan, ideally as a ‘one-stop shop’, probably as a CAA webpage.

Iteration 3

As a result of this engagement exercise, we have decided to make changes to the stages at which the masterplan will present proposed trade-off solutions. The proposal in CAP 1887 was that ACOG will include in Iteration 3 actual proposed trade-off solutions to the conflicts and interdependencies identified in Iteration 2. We have now decided that Iteration 3 will not propose one design option in preference to another. The masterplan will now only propose trade-off solutions in subsequent iteration(s).

We have done this to ensure that the final iteration(s) of the masterplan is/are the product of analysis carried out by individual airspace change sponsors. That analysis will be based on the output of the consultation stage (Stage 3) of the sponsors’ individual constituent CAP 1616 process airspace change proposals. These Stage 3 consultations will be an important opportunity for stakeholders to influence decisions on proposed trade-off solutions that may affect them (see below). ACOG will include in Iteration 3 a description of how specific design trade-offs between interdependent airspace change proposals could be resolved conceptually. Iteration 3 will be based on the outputs of Stage 2 and 3 work carried out by sponsors during the CAP 1616 process.

Final iteration

Iteration 4 (and potentially subsequent iterations) will show the complete, detailed plan of airspace changes setting out how ACOG, working with airspace change sponsors, envisages that any conflicts between interdependent airspace change proposals are resolved, i.e. include proposed trade off decisions.


ACOG will consider the views of individual stakeholders at the strategic, masterplan level through a public engagement exercise on a draft of Iteration 3. This includes views on the way the masterplan proposes conceptual solutions to potential conflicts between interdependent airspace change proposals, and views on any potential gaps or improvements in the masterplan. Through this engagement ACOG will make stakeholders aware of the upcoming consultations on each constituent airspace change proposal, how they are linked together, and how stakeholders can input into proposed trade-off decisions that may affect them.


We have introduced greater flexibility into the acceptance criteria:

  • when submitting Iteration 2 for acceptance, ACOG is required to include a plan for the content of later iterations; we will keep the acceptance criteria in CAP 2156a for Iteration 3 and beyond under review and update them as circumstances require
  • in development of a particular iteration, ACOG may choose to make a case to the CAA and Department for Transport as co‑sponsors during the ongoing assessment process that a particular element in the criteria should be moved between iterations, or omitted should it no longer be relevant or proportionate to the required outcome
  • we recognise that there may be more iterations than the four described in our engagement document CAP 1887
  • in order to progress the modernisation programme most efficiently, it may be beneficial for ACOG to divide the masterplan into separate ‘clusters’ with different timelines, each with a set of interdependent airspace change proposals; the co-sponsors will consider ACOG’s advice on this and will accept these clusters in any accepted version of Iteration 3
  • we have made clear that we will need to update the acceptance criteria over the lifetime of the masterplan.

Masterplan development

We have made clearer that the acceptance criteria focus on outcomes for the masterplan, rather than prescribing a specific process ACOG must follow. ACOG will be required to explain milestones, assumptions and the process it is using to develop the masterplan iterations, including how it arrives at proposed solutions for resolving conflicts. The co-sponsors will be assessing whether ACOG is following this approach and delivering the required outcomes while remaining consistent with the legal and policy framework.

Environmental assessments

We have added to the criteria that a strategic environmental assessment and Habitats Regulation assessment will need to be developed for the masterplan. These assessments are a fundamental part of, and therefore must inform, ACOG’s development of the masterplan. The CAA is legally responsible for ensuring that these assessments are carried out in respect of the masterplan. We will, in due course, set out what ACOG’s role is in these assessments, and where in the process this occurs. The acceptance process will ensure that these assessments have been carried out and acted upon appropriately.

General Aviation

The acceptance criteria already required the masterplan to include information about the cumulative impacts of different design choices. We have added to the criteria a specific requirement for ACOG to include in each iteration of the masterplan an assessment of the potential positive benefits or negative impacts on airspace usability, including on the General Aviation sector overall.

CAA procedure to review airspace classification

We have recognised in the masterplan assessment framework (CAP  2156b) that there could be an interaction between the CAA’s new procedure to review airspace classification and the masterplan where the volume of airspace concerned is the subject of an airspace change proposal which forms part of the masterplan. The CAA would formally notify the sponsor concerned of the evidence derived as part of the classification review and also inform ACOG as masterplan coordinator.

CAP 2157 explains in more detail how we took into account your responses to the engagement exercise in the acceptance criteria.

Published responses

View submitted responses where consent has been given to publish the response.


The UK Civil Aviation Authority’s (CAA) 2018 Airspace Modernisation Strategy sets out a new shared objective between the CAA and the Government for modernising airspace which is to deliver quicker, quieter and cleaner journeys and more capacity for the benefit of those who use and are affected by UK airspace.

Of the 15 initiatives that form the Strategy, two are known as Future Airspace Strategy Implementation – South, and Future Airspace Strategy Implementation – North (known as FASI-South and FASI-North respectively). These are complex airspace design programmes that require coordination between the different ‘sponsors’ of airspace changes, such as airports and NERL. The CAA and the Department for Transport (DfT), have commissioned NERL to establish an impartial team known as the Airspace Change Organising Group (ACOG) to lead the programme to create a coordinated implementation plan for airspace changes in Southern UK. This is being referred to as the Masterplan for short. 

The purpose of the Masterplan is to set out where airspace change could be taken forward to provide benefits, to consider potential conflicts, trade-offs and dependencies, and set out a preferred implementation plan. The Masterplan does not set the detail of individual airspace designs or solutions. It will however, identify where any airspace changes would be needed to deliver a range of benefits, including to reduce noise, deliver air quality or fuel efficiency benefits or where more direct routes are possible that could reduce controlled airspace.


Why your views matter

The Masterplan which ACOG produces will need to be formally assessed and accepted into the CAA’s Airspace Modernisation Strategy, in order to give it a statutory basis. Acceptance of the Masterplan into the CAA Strategy makes the Masterplan, together with CAP 1616, the legal basis against which the individual airspace change decisions are made by the CAA.

The CAA and DfT need to be reassured that the Masterplan identifies the conflicts, and trade-offs associated with airspace redesign, as well as how ACOG propose to resolve these, including how they align with relevant policy.

Your feedback is being sought on the criteria that the CAA proposes to use to determine whether to accept the Airspace Change Masterplan into the Airspace Modernisation Strategy.  The proposed criteria are detailed in CAP 1887 which is available to download at the bottom of this page. It covers the proposed assessment and acceptance criteria, including relevant policy considerations, as well as expectations for engagement on the development of the Masterplan.



The UK Civil Aviation Authority has made the decision to further extend the deadline of this public engagement.  This will allow stakeholders a greater opportunity to input into the engagement exercise despite the disruption caused by COVID-19.

The public engagement exercise will now close on 26 June 2020.

What happens next

This engagement closed on 26 June 2020 after 17 weeks.  We may seek further views if it becomes apparent through analysing the engagement that we have not received a broad spread of views.

The airspace modernisation programme is a long-term programme and some time will need to be taken to consider this document in the context of the disruption caused by Covid-19.  It is likely that we will be taking a longer time than usual to publish our post-engagement analysis but will update stakeholders in due course.

Thank you to those who have submitted their views.

Responses, where we have consent to publish, can be viewed by following the link above under 'Published Responses' (for online responses) and the link at the foot of this page under 'Related' (for offline responses).  


  • Residents affected by aviation
  • Organisations affected by aviation
  • Community groups
  • Airline passenger
  • General Aviation
  • Commercial airlines
  • UAV operators
  • Air taxi operators
  • Military
  • Airport operators
  • Air Navigation Service Providers
  • Industry representative bodies
  • Eurocontrol
  • Flightcrew
  • Air traffic control staff
  • Tour operators
  • Travel agents
  • Cargo shippers
  • Ground handling providers
  • Aerodrome Operators
  • RFFS Training Providers
  • Training organisations
  • FISO licence holders
  • ATS initial training organisations
  • Government departments
  • Regulatory bodies
  • Elected political representatives
  • European Aviation Safety Agency
  • European Commission
  • International Civil Aviation Organization
  • National representative organisations or institutes
  • Workers' representative bodies
  • Autogyros
  • Balloons
  • Drone owner
  • Drone operator
  • Model aircraft enthusiast


  • Aircraft noise
  • Aircraft emissions
  • Local air quality
  • Flightpaths
  • Airspace design, categorisation and access
  • Airspace change proposals
  • Airspace investment
  • Air Traffic Control
  • Economic regulation
  • Capacity
  • Economic regulation
  • Baggage
  • Punctuality
  • Safety
  • Security
  • Consumer protection
  • Disability rights
  • Air Traffic Control
  • Rescue and fire fighting
  • Gyroplanes
  • FISO training, qualification and licensing
  • Airworthiness
  • Light aircraft
  • Flying Displays and Events
  • Microlights
  • Training
  • Drones