Airspace classification review 2019–2020

Closed 3 Mar 2020

Opened 17 Dec 2019

Published Responses

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


The CAA would like you to help us identify volumes of controlled airspace in which the classification could be amended to better reflect the needs of all airspace users on an equitable basis.

How do I respond?

Please complete the survey below. You will probably find it helpful to review the visualisations of controlled airspace and their use. These images are ordered by geographical area of the UK (north, midlands and south) and then by height (presented as a flight level) and representative times of day, because airspace is used differently at different times. The air traffic presented is derived from NATS radar data and within +/- 500 feet of the presented flight level. We have focused on four flight levels, based on those that are of most interest to a range of users: FL20 (i.e. 2,000 ft), FL40, FL60 and FL100.

What happens next?

Once this consultation closes, there will be three more stages to complete the work:

  1. Shortlisting volumes of airspace for potential amendment

    First, the CAA will analyse the responses from this consultation and the evidence that we can collate in collaboration with those responsible for management of airspace. We will then draw up a shortlist of those volumes of airspace where we think the classification could be amended and consider the best options for such amendments. 

    For example, it might be that the volume of controlled airspace could be reduced, with a section of it removed, or it might be that it remains the same size, but its classification could change, and therefore probably the traffic service provision within it. An alternative option – particularly if it is used by commercial traffic at some hours but not others – might be to make the classification flexible, i.e. to switch its classification and services on and off at different times. In developing amendment options, the CAA will need to ensure alignment with ICAO guidance on airspace design and to consider the safety, operational and environmental implications.

    There might be other ways of achieving the long-term outcome of better reflecting the needs of all users. If an airspace change is being developed in a volume of airspace, we may choose not to consider amending the classification of that volume at the present time, if we believe the best outcome would be to see how the airspace change develops or performs.
  1. Developing a new regulatory process for amending the classification of a volume of airspace

    Second, the CAA will develop a new regulatory process to implement the amendments. We will publicly consult about what that process should look like before we implement it. The process we envisage will follow a series of steps before we decide whether to amend a specific volume of airspace. One of those steps will be a formal consultation on the specific amendment proposed to a volume of airspace. The new regulatory process will need to be in place before those consultations can begin.
  1. Developing solutions to enable airspace reclassification

    Finally, there will also be enabling work to develop some of the solutions that may be employed. For example, the flexible use of airspace (meaning to amend or switch off its classification and services at different times) will need new procedures and supporting technologies to be introduced. It will be important to have dissemination and assurance-of-receipt of the status of a particular block of airspace. For example, if a General Aviation aircraft is using airspace while the airspace classification is ‘off’ but needs to be contacted before it can be switched back ‘on’, thereby allowing commercial operations to be safely resumed, it must be possible to correctly identify and communicate with that General Aviation aircraft.

    It may be the case that new requirements and technology are introduced to support such flexibility; this is something the CAA will have to develop. Our Innovation Hub, together with our Future Airspace Team, is exploring how to test technologies which could deliver electronic conspicuity. A ‘sandbox challenge’ would set out what we are seeking to establish through the test and the support that would be available to innovators in answering those questions. The Innovation Hub hopes to make an announcement on this early in 2020.

How will the CAA decide which volumes of airspace are shortlisted?

We will use the following evidence and analysis to decide which are the priority volumes of airspace in which the classification could be amended:

Responses to this consultation:  

  • We will be interested in volumes of airspace that are identified by more than one respondent, as this suggests that more than one person or entity would benefit from its amendment.
  • We will also be interested in respondents who suggest a particular volume of airspace cannot be safely amended.
  • While we will look for common themes and suggestions among respondents, this exercise is not simply a vote or a referendum – we will consider the full opportunities and risks for the volumes identified by respondents, rather than just their popularity.

Analysis of technical data about safety and other important factors. The data we will analyse may include:

  • Airspace infringement data based on submitted mandatory occurrence reports (MORs)[1] and relevant airport surveillance-derived data.
  • Planned operations (a view of what was planned) including flight intention data; this would include visual flight rules (VFR) intended plan data.
  • Actual operations (what was actually flown) including en-route radar data, airfield approach surveillance data, and electronic conspicuity source data.
  • Safety data (formal reported issues and quantitative feedback of issues) including Local Airspace Infringement Team information, reported bottlenecks and areas of intense General Aviation operations near volumes of controlled airspace.
  • Service data (supporting evidence of levels of air traffic service, airspace and aerodrome use) including commercial air services and General Aviation airspace access or crossing refusals.


Why is the CAA doing this?

On 30 October 2019 the Secretary of State for Transport wrote to the CAA[2] to amend the 2017 Air Navigation Directions[3] to give us a new role regarding the way in which airspace is classified. Directions 3(a), (b) and (ba) come into force on 1 April 2020. They state that the CAA must:

(a) develop and publish a national policy for the classification of UK airspace;

(b) classify UK airspace in accordance with such national policy, publish such classification, regularly consider whether such classification should be reviewed, carry out a review (which includes consultation with airspace users) where the CAA considers a change to classification might be made and, as the CAA considers appropriate, amend any classification in accordance with procedures developed and published by the CAA for making such amendments;

(ba) in developing the national policy referred to in sub-paragraph (a), classifying UK airspace under sub-paragraph (b), or amending the classification of a volume of airspace under that sub-paragraph, seek to ensure that the amount of controlled airspace is the minimum required to maintain a high standard of air safety and, subject to overriding national security or defence requirements, that the needs of all airspace users is reflected on an equitable basis;

This now means that we must:

  • regularly consider whether to review the classification of airspace;
  • consult airspace users as part of that review;
  • where we consider a change to classification might be made, amend it ourselves in accordance with a new procedure that we must develop and publish;
  • in developing that procedure and our policy describing airspace classifications, seek to ensure that the amount of controlled airspace is the minimum required to maintain a high standard of air safety and, subject to overriding national security or defence requirements, that the needs of all airspace users are reflected on an equitable basis.

The CAA has decided to review the classification of UK airspace and conduct our first review now, and this consultation forms part of our first review. The CAA has considered its obligation to consult with airspace users in carrying out the review and developed this public consultation to do so. As explained above, we will, separately, develop a new regulatory procedure for considering solutions and if possible amending the classification of the volumes of airspace that are identified through the review.

What does the airspace classification review seek to achieve?

As the Directions state, we need to “ensure that the amount of controlled airspace is the minimum required to maintain a high standard of air safety and, subject to overriding national security or defence requirements, that the needs of all airspace users is reflected on an equitable basis.”

This means we want to review airspace classifications in the UK to reflect the needs of a range of airspace users – including commercial aviation, General Aviation, and new technologies such as drones and spaceflights – on an equitable basis, and we must do so safely. However, while equitable means fair and reasonable, it does not mean that all airspace users must have equal access to a volume of airspace. For example, small drone operations are usually performed locally and below 400 feet, which is a very different airspace need to that of a private pilot licence holder flying cross country.


Why are there so many consultations, why can’t you just amend the airspace quickly?

Some of the reasons for there being different stages to this work are explained above, under ‘What happens next?’. For example, there may need to be new procedures, training and equipage for making use of airspace in a more flexible way.

The Air Navigation Directions require us to consult airspace users when we review whether airspace classifications can be amended; that’s what we’re doing in this consultation. But we will also have to a) consult on the new regulatory process for considering amendments to airspace classifications in the future (this will be a one-off) and b) as part of that new regulatory process, consult on specific reclassification proposals before we make any amendments.

This new regulatory process includes consultation so that when we propose to amend a specific volume of airspace we capture all evidence and opinion to ensure we do the right thing. We need to understand all the implications of the amendment, including considering whether the classification can be amended safely and hearing the views of those using or affected by the airspace classification.

How does this relate to airspace modernisation?

The UK’s airspace structure is an essential, but largely invisible, part of our national transport infrastructure. It is divided into controlled and uncontrolled airspace, and further divided into classifications. There are rules attached to classifications about how and where aircraft can fly, and the air navigation services and procedures that must be used. The UK’s skies are accommodating increasing numbers of commercial flights, military activities and an active General Aviation sector, as well as new technologies such as drones.

The vast majority of commercial flights operate solely in controlled airspace; recreational flying and aerial sports operate largely in uncontrolled airspace below 6000 feet, alongside a few commercial and business flights. The military also has significant requirements to use both types of airspace and occasionally also operates within the confines of segregated training or danger areas. The creation of controlled airspace may impinge on the availability of airspace for other users, and an appropriate balance is needed to satisfy both the safety needs and economic requirements of the various types of, often conflicting, operational requirements. At lower altitudes there is more of a challenge in balancing the differing requirements of a more diverse range of affected parties.

Many air routes and air traffic management practices are not fully utilising the modern technologies available, and aircraft continue to use prescribed flightpaths that are outdated. Those flightpaths often constrain aircraft climb performance such that more time is taken for them to reach their optimum cruising altitude. This creates inefficiencies and results in greater fuel burn, more emissions and larger blocks of controlled airspace to contain such procedures. Flightpaths may not presently be optimised to reduce noise impacts or designed to offer relief from noise. This inefficient use of airspace causes unnecessary delays for passengers and significant air traffic control workload to manage bad weather or other forms of disruption. It also has excessive impacts on the environment and those living near our airports. The outdated design is also, crucially, constraining the number of flights that the airspace can safely accommodate.

With these challenges in mind, the CAA’s Airspace Modernisation Strategy (AMS) set out 15 initiatives to modernise airspace. The airspace classification review sits in a strategic context which includes the following existing AMS initiatives:

  • Reviewing the UK’s application of the ICAO airspace classifications, the related air traffic management requirements to ensure that the airspace is optimised for all airspace users in all phases of flight, and the conspicuity solutions to make airspace more flexible for different uses (AMS initiatives 9–11).  
  • This included an airspace classification review. The work explained above builds on this initiative. The work already being undertaken will inform a long-term plan that will be built into future iterations of the review.
  • Implementing an airspace change masterplan that applies the new concepts and aims to reduce controlled airspace through changes to both existing and future planned airspace (noting that these changes must also consider other factors such as commercial growth) (AMS initiatives 4–8). The masterplan and the analysis and engagement that must feed into it have been commissioned from a new unit in NERL (ACOG – the Airspace Change Organising Group).

Work on these initiatives will continue and the co-sponsors of airspace modernisation, the CAA and Department for Transport, expect every organisation responsible for the delivery of initiatives to engage relevant stakeholders and coordination across the initiatives to ensure coherent delivery.

[1] Mandatory Occurrence Reporting requires the reporting, analysis and follow up of occurrences in civil aviation and delivers a European Just Culture Declaration. An occurrence means any safety-related event which endangers or which, if not corrected or addressed, could endanger an aircraft, its occupants or any other person. The purpose of occurrence reporting is to improve aviation safety by ensuring that relevant safety information relating to civil aviation is reported, collected, stored, protected, exchanged, disseminated and analysed. It is not to attribute blame or liability.

[3] The Civil Aviation Authority (Air Navigation) Directions 2017, as amended by The Civil Aviation Authority (Air Navigation) (Amendment) Directions 2018 and The Civil Aviation Authority (Air Navigation) (Amendment) Directions 2019. A consolidated version is on the CAA website.


  • Residents affected by aviation
  • Organisations affected by aviation
  • Community groups
  • General Aviation
  • Commercial airlines
  • UAV operators
  • Air taxi operators
  • Military
  • Airport operators
  • Air Navigation Service Providers
  • Industry representative bodies
  • Eurocontrol
  • Air traffic control staff
  • Aerodrome Operators
  • Government departments
  • Regulatory bodies
  • Elected political representatives
  • Autogyros
  • Ballons
  • 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
  • Air Traffic Control
  • Gyroplanes
  • Light aircraft
  • Drones
  • Model Aircraft