CAA consultation launched (ends 15th June) on the process of airspace change

The CAA has launched it long awaited consultation on the process of airspace change. One of the reasons has been the unprecedented level of opposition, anger, frustration (and in some cases despair) caused by the unsatisfactory manner in which flight path changes have been introduced in recent years. The CAA, NATS and the airports have lost what confidence the public had in them before, due to their inabilities to communicate properly with those suffering from aircraft noise problems. The CAA says: “While not everyone will agree with every potential decision on how we develop the infrastructure of our airspace, the methods used to reach those decisions need to be well understood and accepted. One of our aims is to restore confidence in the process where it is currently lacking.” The CAA says one of the ways to make their processes more transparent and publicly accessible is: “an online portal to provide a single access point for anyone to view, comment on and access documents for every UK airspace change proposal.” However, many important and relevant areas are outside the consultation, such as Government policy, which the CAA’s process must follow, and “changes to flight paths which result from decisions made by air traffic control providers and outside the CAA’s control”. The full document is 140 pages in length, and will take time for those who plan to respond to fully understand.

The consultation ends on 15th June. 




15.3.2016 (The CAA – Civil Aviation Authority)

Link to the full (140 page) consultation document

CAA consultation logo

The CAA has launched a major consultation on how decisions are made on proposed changes to the UK’s airspace structure.

It seeks views from stakeholders, ranging from the aviation industry and general aviation to people affected by aircraft noise, on a series of proposals aimed at making the airspace change process more transparent and giving the CAA a more hands-on role.

The airspace change process

If someone, usually an airport or air traffic control body, wants to request a permanent change to the UK airspace structure they must submit a proposal to the CAA, which goes through our airspace change process.

The CAA is consulting on proposed improvements to this process, which is used to decide whether a change goes ahead. Our suggested changes are supported by an independent review carried out in 2015 by specialist consultants Helios.

The consultation

The consultation therefore details changes to the process a proposal goes through, which includes consultation with local communities, and also how it can be made more transparent.

One of a range of recommendations under consideration to achieve this is an online portal to provide a single access point for anyone to view, comment on and access documents for every UK airspace change proposal. The effectiveness of the process could also be improved by additional stages of scrutiny and validation.

The consultation is not about areas which are outside of the CAA’s airspace change process, such as Government policy, which the CAA’s process must follow. Government policy on issues, such as whether flight paths are concentrated along a narrow path or deliberately dispersed, whether flight paths are alternated to provide periodic respite from noise, and whether tranquil areas are avoided, are not part of the CAA consultation.

The consultation which is open to everyone is available until 15 June 2016 and can be accessed at


Link to the full (140 page) consultation document

What is out of scope of this consultation (what we are not consulting on)

There are a number of aspects of airspace change that are not within the scope of this consultation. Consequently, the CAA will not consider or act upon any responses that focus on these areas, which are detailed below.

Matters of government policy

This consultation document is not about matters which are outside of the CAA’s airspace change process. This includes government policy, which the CAA’s process must implement, and which we will discuss with the Government but which ultimately the CAA has no control over. The consultation also assumes that the respective CAA and Secretary of State functions in respect of airspace remain unchanged. If any aspects of these were to change there may be an impact on the CAA’s process, which we would have to take into account and address at that time.

Below is a list of some of the policy areas where there could be a knock-on impact on the CAA process:

 Changes to the statutory guidance which the Secretary of State gives the CAA on how it should take environmental impacts into account (see Chapter 2). This includes, by way of example: the policy objective to limit and where possible reduce the number of people in the UK significantly affected by aircraft noise; whether flight paths are concentrated along a narrow path or deliberately dispersed; how and whether aircraft tracks are alternated to provide periodic respite from noise; and whether tranquil areas are avoided.

 Matters of national defence and security

 Matters relating to the implementation of European law which is binding on the UK

 Whether changes to flight paths where the ‘notified’ airspace structure is unchanged are subject to an approval process

 The ‘noise preferential routes’ set by the Secretary of State at Heathrow, Gatwick and Stansted airports for aircraft departures

 Whether the Government decides to implement recommendations by the Airports Commission to create an ‘Independent Aviation Noise Authority’, a new noise engagement forum, or a compensation scheme

 The standard metrics for quantifying the amount and level of noise.

The Government may review and update its policies and any of the documents noted above. For example, it may choose to consider the Airports Commission’s recommendation to create an Independent Aviation Noise Authority. The CAA’s airspace change process will need to be flexible to respond to policy changes as and when they happen. We believe this is a matter for the CAA and Government to discuss and agree, and we will not re-consult on our process unless policy changes are of such a substantial nature that we consider we have to, or the Government explicitly requests us to do so.

Changes to flight paths which result from decisions made by air traffic control providers and outside the CAA’s control

Some changes to flight paths can be made by the air traffic control provider on a long-term tactical basis by altering its procedures without the CAA needing to be notified. This is essentially where operational and safety requirements necessitate an airspace structure where there is flexibility as to the exact flight paths followed. Within such areas, for the purposes of safety and service delivery, air traffic controllers may issue directional instructions to aircraft which are either not aligned with a published flight path or where no such published flight path exists. Guidelines on noise such as following Noise Preferential Routes and descending from optimum heights to minimise noise disruption are still adhered to. It has been argued that where such tactical changes to flight paths lead to a planned permanent redistribution of noise, they ought to be subject to a similar process. This would require a change in government policy which, if undertaken, may result in a change to the Directions from the Secretary of State to the CAA. This is not covered in this consultation. If the Directions to the CAA were changed, we would review our process and consult on any changes to it if necessary.

CAP 725

The CAA say: “We will only redraft CAP 725 once we have heard your views, and therefore we are not consulting on a replacement document at this stage. We expect to seek stakeholders’ views on the redrafted version in early 2017. Airspace changes that have recently been approved, or are currently going through the airspace change process, are also out of scope. This consultation concerns the process and how it may change in the future, not the specific details of current or developing proposals which adhere to the current process.”



The CAA main webpage about this consultation states:

Proposals for a revised airspace change process


The purpose of this consultation is for the CAA to learn your views on some changes we are considering making to our airspace change decision-making process. Our objective is to optimise our process to ensure that all stakeholders are adequately consulted as part of a transparent, proportionate process. The process should be impartial and evidence-based, and should take proper account of the needs and interests of all affected stakeholders.

This consultation sets out why we believe a review is necessary, and the main findings of Helios, the consultants who carried out an independent review of the process on our behalf. We explain the main principles behind our proposed changes, and, in Chapter 4, details of the specific changes we are considering to each stage of the process. We discuss the impacts we anticipate our proposed changes will have, and invite you to share evidence so we can define these further. In Chapter 6 we also set out the statutory duties the Government has set the CAA, and how we use these in making decisions about airspace. However, this consultation is not about government policy, which is not a matter for the CAA. Neither is it about specific airspace changes that have already happened, or are currently moving through the stages of the existing process.

In addition to these pages, we have also made a full, detailed consultation document available. The questions and text remain the same, but on this online version of the consultation we have reduced some of the text available in the full document.

and it continues:


What are airspace and the airspace change process?

In its simplest terms, airspace is the portion of the atmosphere controlled by a State above its territory and areas over the sea within which a State is contracted by the International Civil Aviation Organization (ICAO) to provide air traffic services. It is an invisible national asset. For air traffic control purposes, airspace can be divided into two main categories, controlled and uncontrolled. Controlled airspace is where air traffic control needs to have positive control over aircraft flying in that airspace to maintain safe separation between them. Uncontrolled airspace is airspace where aircraft are able to fly freely through the airspace without being constrained by instructions in routeing or by air traffic control, unless they request a service.

Controlled airspace contains a network of corridors, or airways. They link the busy areas of airspace above major airports. At a lower level, control zones are established around each airport. These portions are therefore nearer the ground and closer to population centres. Because controlled airspace carries with it requirements that affect the aircraft and pilots that fly in it, an airspace change can impact the users of airspace in different ways.

The CAA is responsible for approving the overall layout of the published airspace structure and any proposed changes to it.[1] We do so in the context of legal requirements which include safety, the environment and the needs of the consumers of aviation services as well as other duties all set out in section 70 of the Transport Act 2000. For example, changes might be needed to enable UK airspace to accommodate more flights, to incorporate new technology, to allow aircraft to fly more direct routes or to keep them away from particular areas. When we are asked to consider a change to the structure of UK airspace we will consider whether there is any reason why the change ought not to be made. Before agreeing to approve any change we then have to consider safety, environmental impacts (including aircraft noise and emissions) and operational factors.

We therefore require the proposer or ‘sponsor’ of any permanent change to the published airspace structure to follow our airspace change process. 

Figure 2.1: Overview of the airspace change process as published in CAP 725

Current process outlining stages 1-7. Full details on page 24 of consultation document.

These stages begin with outline conversations between the sponsor and the CAA around design options and who should be consulted. The sponsor then consults with interested parties, including, where appropriate, local communities. In the light of responses the sponsor may modify the proposals before making a formal submission of the proposal to the CAA for a decision. Assuming that the proposal is approved, the CAA carries out a review of the change after it has been implemented, typically after one year of operation.

Reasons for changing the current process

The CAA is proposing changes to the current airspace change process because:

  • The airspace structure is a key part of the UK’s national infrastructure but is in need of modernisation. If modernisation is held up, there will be significant impacts not just on air passengers and shippers but also the wider economy. The CAA believes that modernisation of airspace can offer a range of benefits, and in some cases modernisation is required by international obligation. However, it is for the aviation industry to develop specific proposals for change. The CAA needs a rigorous process for ensuring that we can make robust and lawful decisions about those proposals. We will not make a change simply because it enables modernisation; we will only do so once we have also given consideration to the range of factors and stakeholders we have a duty to consider.  Airspace modernisation requires the CAA to consider airspace change proposals on a scale unprecedented in recent years. These proposals may change flight paths[2] and therefore noise impacts, and may also impact airspace users and service providers.
  • Those affected should have the ability and opportunity to respond to consultation before a change is made. The CAA’s decisions on airspace change must balance and take proper account of the needs and interests of all affected stakeholders.
  • Airspace is a finite resource and there are competing demands for it from airspace users with differing needs (commercial air transport, General Aviation, military, unmanned aircraft and so on).  Again, these must be balanced against each other.
  • Communities close to airports increasingly demonstrate their interest in the management of aviation noise and the impact it has on those communities. Some recent airspace change proposals have highlighted a lack of trust between some local communities, the aviation industry and the CAA as regulator. This can sometimes create an impasse on airspace changes – changes which, in totality, might achieve an improved outcome in respect of all the factors we have to consider (although, as a consequence, an individual stakeholder may be in a worse position than if no change were made).
  • It is therefore essential that the CAA’s airspace change process meets modern standards for regulatory decision-making, and above all else is seen as fair, transparent, consistent and proportionate.
  • We need to ‘future-proof’ the process in the light of changing international requirements that are binding on the UK as a European Union Member State.
  • The independent Helios report reviewing the current process found that it could be improved and recommended a number of changes, on which, with some modifications, the CAA has decided to consult.


Our objective is to optimise our airspace change process to ensure that all stakeholders are adequately consulted as part of a transparent, proportionate process. The revised process should be impartial and evidence-based, and should take proper account of the needs and interests of all affected stakeholders. These stakeholders, in no particular order, include:

  • the users of air transport services, i.e. passengers and shippers;
  • those on the ground affected by aviation noise or other environmental impacts;
  • the users of airspace, including commercial operators, General Aviation and the military;
  • other service providers such as air traffic control and airports;
  • others with a legitimate interest, such as environmental bodies and councils.

In doing so we must consider what those needs are today and what they might be in the future. While not everyone will agree with every potential decision on how we develop the infrastructure of our airspace, the methods used to reach those decisions need to be well understood and accepted. One of our aims is to restore confidence in the process where it is currently lacking.

It is also very important that in improving and optimising the airspace change process the CAA does not raise expectations that the new process will give everybody everything that they want. The airspace change process is not designed to be a referendum on views, but it is designed to reach an outcome fairly having regard for the views of all the various stakeholder groups and having considered those views in accordance with section 70 of the Transport Act 2000. To achieve this compromise outcome, there will have to be trade-offs where there are conflicting requirements, which could mean winners and losers. Every airspace change proposal is different and is considered on a case-by-case basis, but often these trade-offs are a matter for the over-arching government policy.

The Helios review of the airspace change process

In 2015, the CAA commissioned management and technology consultants Helios to undertake an independent study of our existing airspace change process. As part of this work, we asked Helios to consult with a range of stakeholders that either use the process or are affected by the decisions resulting from it, and then provide recommendations on how the process could be improved. As part of its review, Helios tested various hypotheses in stakeholder workshops and through an online stakeholder survey. Helios consulted and spoke to representatives of airspace change sponsors, airspace users (including private flyers), and communities. We published Helios’s report on our website[3] on 8 December 2015.

Helios proposed a revised airspace change process based on the current process but with greater transparency and more stages, with approval at certain key points and the CAA being more hands-on than at present, particularly for the consultation phase. Helios recommended that an independent airspace change Oversight Committee be involved for the most significant changes, and that an appeal mechanism be introduced. Helios also proposed that an online portal be established holding all relevant information on airspace change proposals and collecting consultation responses. Helios recommended that the CAA seek greater clarity and guidance from the Government on policy and strategic priorities associated with airspace change.

The CAA‘s preliminary view is that most of Helios’s recommendations appear to address the issues identified with the current process. Our proposals for a revised process on which we are consulting are therefore largely based on what is recommended by the Helios report, with some important modifications which are explained in Chapter 4.



Link to the full (140 page) consultation document