Legislative framework to airspace change

The CAA’s statutory duties and functions in relation to airspace change are contained in the Transport Act 2000 and the Civil Aviation Authority (Air Navigation) Directions 2023.

The Civil Aviation Authority (Air Navigation) Directions

Please note that the Civil Aviation Authority (Air Navigation) Directions 2017, as amended, have been revoked and replaced by the Civil Aviation Authority (Air Navigation) Directions 2023. Any CAA documents published before April 2023 that refer to the Air Navigation Directions 2017 should be read as if they refer to the relevant and corresponding provision of the Civil Aviation Authority (Air Navigation) Directions 2023.

The Secretary of State has given the CAA the function of approving changes to the design of airspace in the Civil Aviation Authority (Air Navigation) Directions 2023.

The Directions require the CAA to develop and publish procedures, and guidance on such procedures, for the development, making and consideration of a proposal for a permanent change to airspace design, a temporary change to airspace design, or an airspace trial. This procedure and guidance are published as CAP 1616 Airspace Change. Any procedure must be proportionate and reflect published Government policy. The airspace design approved by CAA is published in the UK Aeronautical Information Publication (AIP).

Under the 2023 Directions, the CAA has a duty to decide whether to approve changes to airspace design in accordance with the Airspace Modernisation Strategy. In performing this duty, the CAA ensures that the airspace change proposal aligns with the vision and strategic objectives of the Airspace Modernisation Strategy, as well as any iterations of the Airspace Change Masterplan, where applicable, that have been accepted into that strategy. This means that any change sponsor must take account of the Airspace Modernisation Strategy and accepted iterations of the Airspace Change Masterplan, where applicable, in the development of their airspace change proposal such that it is not inconsistent with the delivery of that strategy and plan. More information on the Airspace Modernisation Strategy, its vision and strategic objectives can be found here.

The 2023 Directions also require the CAA to publish a prioritisation principles document setting out our general approach to the order in which we will consider airspace change proposals submitted for regulatory decision. That document must take into account the Airspace Modernisation Strategy and any associated implementation plans, the priority that needs to be given to urgent safety and national security proposals, and any other policy objective notified to the CAA by the Secretary of State.

The 2023 Directions also introduce a new requirement for the CAA to monitor and investigate incidents of lost communications between ground-based civil air traffic controllers and civilian pilots. The CAA must provide civilian pilots with a proportionate ongoing awareness programme and publish an annual report covering its investigations.

Section 70 of the Transport Act

Section 70(1) of the Transport Act 2000 places the CAA under a general duty when deciding whether to approve airspace change proposals to do so in a way that maintains a high standard of safety in the provision of air traffic services. That duty is to have priority over the CAA’s other duties in this area of work. Noting that priority, section 70(2) then requires the CAA to decide airspace change proposals in the manner it thinks best so that:

• it secures the most efficient use of airspace [see definition 1] consistent with the safe operation of aircraft and the expeditious flow of air traffic. [see definition 2]
• it satisfies the requirements of operators and owners of all classes of aircraft
• it takes account of the interests of any person [see definition 3] (other than an operator or owner) in relation to the use of any particular airspace or airspace generally
• it takes account of any guidance on environmental objectives given to the CAA by the Secretary of State
• it facilitates the integrated operation of air traffic services provided by or on behalf of the armed forces and other air traffic services
• it takes account of the interests of national security
• it takes account of any international obligations of the UK notified to the CAA by the Secretary of State.

Definitions

1. The CAA uses the following overall definition of “the most efficient use of airspace”: The most aircraft movements through a given volume of airspace over a period of time in order to make the best use of the limited resource of UK airspace from a whole system perspective.
2. The CAA uses the following definition of “expeditious flow”: The shortest amount of time that an aircraft spends from gate to gate, from the perspective of an individual aircraft, rather than the wider air traffic system.
3. The CAA considers the words “any person (other than an operator or owner of an aircraft)” to include airport operators, air navigation service providers, members of the public on the ground, owners of cargo being transported by air, and anyone else potentially affected by an airspace change proposal.

Our approach to the regulatory assessment of airspace changes

The CAA adopts the following approach when undertaking its regulatory assessment of airspace change proposals.

Step 1: Airspace Modernisation Strategy

The CAA will first consider whether the airspace change proposal is in accordance with the Airspace Modernisation Strategy, including the vision and strategic objectives of that strategy.

Not every airspace change proposal will further all the strategic objectives of the Airspace Modernisation Strategy. Some proposals may contribute positively to one or more objectives and negatively to others. Where such conflicts arise, in deciding whether the airspace change proposal is in accordance with the Airspace Modernisation Strategy, the CAA looks at whether the proposal strikes an appropriate balance across the strategic objectives of the Airspace Modernisation Strategy having regard to that strategy as a whole.

Other proposals, especially those of a highly localised nature, or that propose no changes to the airspace structure, for example, wind farms, may have little or no bearing on the delivery of the Airspace Modernisation Strategy. The CAA does not consider such proposals to be de facto inconsistent with the Airspace Modernisation Strategy, although change sponsors will need to provide an explanation to the CAA where they consider their airspace change proposal to be outside the scope of that strategy.

Step 2: Section 70 of the Transport Act 2000

The CAA will then consider the airspace change proposal against each of the factors in section 70 of the Transport Act 2000.

Subject to maintaining a high level of safety, the CAA will approve an airspace change proposal that contributes positively to all the material factors in section 70(2) and where there is no conflict between those material factors.

Where a particular proposed airspace change would contribute positively to some of the material factors, but negatively in respect of others, section 70(3) refers to this situation as a conflict. Section 70(3) then requires the CAA to apply those material factors in the manner it thinks is reasonable having regard to them as a whole. The CAA will give the duty to “secure” something higher weight than the duty to “satisfy” or “facilitate”. For example, we would give the duty to secure the most efficient use of airspace higher weight than the duty to satisfy owners and operators of aircraft.

The CAA regards the term “to take account of” as meaning that the material factors in question may or may not be applicable in a particular case (for example, national security) and also that the range of ways they could affect our decision could be wide. This means that sometimes, a factor we must “take account of” is prioritised over one we need to “secure”. Not all of the factors will be relevant in all cases.

As envisaged in section 70(3), there may be good reasons why the CAA would not always give greater weight to the matters that it is required to secure. Some examples are given below, but this list is not exhaustive:

• local circumstances – such as where the CAA might make an airspace change that takes account of the noise of aviation over the ability to secure the most efficient use (i.e. where design principles, as described in Stage 2 of the process, mean an airspace design creates less efficient paths that avoid a population centre, where this is supported by the change sponsor and by local communities)
• interdependencies – such as where the CAA might make an airspace change decision that reduces the efficient use of airspace or does not meet requirements of owners and operators in order to meet an international obligation
• magnitude of the impact – such as when the impact of an airspace change on a higher weight factor is small, whereas the impact on a lower weight factor is large
• complexity of the airspace – such as when an airspace structure modified through the consultation process in an attempt to meet different user requirements may render it safe, but almost unusable by operators or owners of aircraft or unworkable by air traffic control
• airspace not at full capacity – such as when it is deemed that securing the efficient use of airspace is less important and it could be appropriate to increase the weight of other factors.

Air Navigation Guidance 2017

Section 70(2) of the Transport Act 2000 requires the CAA to take account of any guidance on environmental objectives given to it by the Secretary of State when it is deciding whether to approve an airspace change. This guidance is the  Air Navigation Guidance issued in October 2017. Its full title is Air Navigation Guidance 2017: Guidance to the CAA on its environmental objectives when carrying out its air navigation functions, and to the CAA and wider industry on airspace and noise management.

The Air Navigation Guidance was last issued in October 2017 following a consultation by the Department for Transport about airspace and noise policy. Additional guidance in relation to spaceflight activities was published in September 2021. The Air Navigation Guidance is not just addressed to the CAA. The Government also expects that it will be taken into consideration by the aviation industry. The Air Navigation Guidance also acknowledges the important role which local communities have in the airspace change process.

Underpinning the Air Navigation Guidance are a number of key overall objectives set by the Government. These include:

• to provide guidance to the CAA under section 70(2) of the Transport Act 2000 and which the aviation industry should take account of
• to ensure that aviation can continue to make its important contribution to the UK economy and at the same time seek to improve the sustainable development and efficiency of our airspace network
• to strengthen the UK’s airspace change process and its transparency, particularly with respect to how local communities are involved within it, and
• to emphasise that the environmental impact of aviation must be mitigated as much as is practicable and realistic to do so.

The Air Navigation Guidance contains the Government’s environmental objectives with respect to air navigation. These environmental objectives are designed to minimise the environmental impact of aviation within the context of supporting a strong and sustainable aviation sector. They are, in support of sustainable development:

• to limit and, where possible, reduce the number of people in the UK significantly affected by adverse impacts from aircraft noise
• to ensure that the aviation sector makes a significant and cost-effective contribution towards reducing global emissions, and
• to minimise local air quality emissions and in particular ensure that the UK complies with its international obligations on air quality.

The Air Navigation Guidance recognises the degree of challenge which can exist in satisfying the expectations of local communities, those impacted by aviation, and the aviation industry’s aspiration to further develop the efficiency of the UK airspace network. For example, a key policy issue is how to retain the benefits of aviation while addressing its environmental impacts, and how the CAA should integrate those considerations when making regulatory decisions on the necessary trade-offs between differing airspace objectives, such as increasing airspace capacity, reducing emissions and managing noise.

Through the Air Navigation Guidance, the Government acknowledges that there are other legitimate operational objectives, such as the overriding need to maintain a high standard of safety, the desire for sustainable development, and the need to enhance the overall efficiency of the UK airspace network, which the CAA and others are required to take into account and consider alongside the environmental objectives of the Air Navigation Guidance.

Air Traffic Management and Unmanned Aircraft Act 2021 Part 1

Part 1 of the Act (‘Airspace Change Proposals’) contains powers for the Secretary of State to give a direction to “a person involved in airspace change” requiring them to progress or co-operate in an airspace change proposal where doing so will assist in the delivery of the CAA’s Airspace Modernisation Strategy. Such persons are air navigation service providers, airports and other persons with functions relating to air navigation. The Secretary of State may delegate certain functions to the CAA by giving a notice to the CAA.

Our publication CAP 2431 Enforcement Guidance and Statement of Policy on Penalties gives more information and explains:

• the CAA’s advisory role regarding the use of the direction powers
• policy and guidance regarding the CAA’s enforcement powers where a direction has been issued, and
• a Statement of Policy on imposing penalties and determining their amount where a requirement in an enforcement order has been contravened.