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UK – EU Transition, and UK Civil Aviation Regulations

To access current UK civil aviation regulations, including AMC and GM, CAA regulatory documents, please use this link to UK Regulation. Please note, if you use information and guidance under the Headings, the references to EU regulations or EU websites in our guidance will not be an accurate information or description of your obligations under UK law. These pages are undergoing reviews and updates.

Airspace Change Proposals Post-Implementation Reviews (PIRs) impacted by COVID 19 - Update February 2022

This page was amended on 17/02/2022

A Post-implementation review is conducted at Stage 7 of the Airspace Change process for CAP 1616 and CAP 725 airspace change proposals. The purpose of the PIR is to enable the CAA to consider whether the anticipated impact and benefits of the change have been delivered. To inform this review, which usually takes place 12 months after the change has been implemented, the change sponsor is required to commence the collection of data on the impacts of the change as soon as the change is implemented and to collect a year of data. The data is used to enable a comparison to be made between pre and post implementation operations. A year of data is required to provide data on all operating conditions which change over the seasons. Indicative PIR data requirements are listed in CAP 1616 and include impact on airspace users, those on the ground and any environmental impacts.

Due to the Covid-19 pandemic and its impact on air operations around the globe, including in the UK, PIR data collection has been suspended since our first website update in August 2020.

Since that time, we have regularly reviewed the position and concluded that the continued impact of the Covid Pandemic on air operations around the globe, continues to result in a very different use of airspace than could have been contemplated pre-February 2020.

We committed to update this page in February 2022 and now provide the following information. Whilst the effects of the pandemic are subtly different to those of six months ago, we recognise that its impacts on airspace use continues to be different to that pre-February 2020 and therefore the evaluation of data for the purposes of a PIR may not enable a direct comparison pre and post implimentation. The CAA therefore considers that the process for recently approved and future airspace change proposals, PIRs should be subject to a review and the CAA intends to consult on the PIR process in the CAP 1616 Airspace Change Process review later this year.

It is the opinion of the CAA that a sufficient increase in air travel, particularly in the commercial air transport sector is now likely throughout 2022 and therefore, for those delayed and outstanding PIRs we now require sponsors to commence data collection for the purposes of PIRs as follows:

Any data collected between 1 March 2020 and 28 February 2022 cannot be used as part of a PIR data set. This statement applies to all implemented ACPs due to commence a PIR.

Sponsors of ACPs should commence data collection from 27th March 2022. A phased approach to commencement of data collection may be taken by sponsors to take account of resourcing requirements. Therefore, commencement of data may be initiated at any point between the 27th March 2022 and 27th September 2022. In all cases the CAA would require that 12 months of data is collected. Should the consultation being conducted by the CAA on the PIR process result in any changes this will be published on the CAA website and articulated to sponsors conducting PIR data collection.

Sponsors should advise CAA Airspace Regulation of the date they are commencing data collection. This date should also be published on the sponsors website to ensure their stakeholders remain informed of progress.

Additionally, where PIR data collection was commenced before the onset of the pandemic our policy remains as amended that:

Any PIR data collected by a change sponsor and any analysis by the sponsor which has been completed by 27 February 2020, can be used to as part of a PIR dataset necessary to complete the PIR review in accordance with CAP 1616 or CAP 725 as appropriate.

  1. Where an ACP has been implemented and more than 9 months PIR data collection has been achieved up to 27 February 2020, the CAA may decide it has sufficient data to conduct the PIR review. Where a change sponsor considers that they have such data, they should contact the CAA Airspace Regulation team to determine if this data is sufficient for the PIR review to take place.

All PIRs of ACPs still following the CAP725 process will be conducted in accordance with the process requirements of CAP1616. However, when assessing the expected impacts against the actual impacts we will use the methodology applied at the time of the original decision (either UK Air Navigation Guidance 2014 or 2017). Any sponsors with queries regarding the above should contact the CAA at Airspace.Policy@caa.co.uk.

Post implementation reviews

Post implementation reviews provide a rigorous assessment by us, as the independent regulator, of whether the anticipated impacts and benefits, set out in the original airspace change proposal and decision, have been delivered and if not to ascertain why and to determine the most appropriate course of action.
The review can be an iterative process and the nature of each review will be determined by the scale and impact of the airspace change itself. The main stages are shown below.

Post implementation review initiated

1. We determine the scope and objectives of the review after discussion with the organisation that requested the change.

This may include:

• A review of what was to be achieved by the change
• Air traffic control/management requirements (safety, delay, capacity efficiencies)
• Military air traffic control/management requirements (if applicable)
• Environmental conclusions
• Effectiveness of the change
• Other benefits or impacts
• Operational impact (feedback gathered from all affected aviation stakeholders)
• A post implementation safety analysis.

2. We identify and confirm the data required from the organisation that requested the change.
3. We may, during our assessment phase, revise the scope and objectives of the review.
4. We may request further information from the organisation that requested the change at any time prior to publication of the report.

Close Post implementation review initiated

Data collection and analysis by the organisation that requested the change

  1. Organisation gathers data and operational feedback and information from stakeholders.
  2. Organisation submits data to us.
Close Data collection and analysis by the organisation that requested the change

Our assessment

  1. We assess the completeness and adequacy of the data submitted.
  2. Where applicable we independently gather aviation stakeholder feedback.
  3. Where applicable we log and analyse written feedback from people and organisations other than airlines, other aircraft operators, airport operators and air navigation service providers.
  4. We assess the operational and environmental impact of the change against the expected impact.
  5. We consider and determine any appropriate consequential action.
Close Our assessment


  1. The organisation that requested the change can provide comments.
  2. The report is published on our website.
Close Report

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