• Airspace Change Proposals Post-Implementation Reviews (PIRs) impacted by COVID 19.

    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. 


    The current pandemic of COVID 19 has seen a dramatic reduction in aviation activities. This global reduction in aircraft movements means that airspace use since March 2020 is unrepresentative of previous years Data collection during this period for the purposes of a PIR would in our view, be unlikely to provide a robust data set against which to conduct that PIR. COVID 19 pandemic has also resulted in a degree of uncertainty within the aviation industry with displacement of aerodrome and Air Navigation Service Providers staff due to initiatives such as the Governments furlough scheme who would normally be undertaking the PIR data collection activity as the airspace change sponsor. Until we have more certainty on the level and behaviour of airspace movements going forward and to better enable airspace change sponsors required to undertake the evidence collection of the data set to business plan ahead, we will suspend the requirement to collect PIR data for those airspace change proposals currently in Stage 7 which fall into the criteria listed below in points 2 to 4 inclusive.


    1. Any PIR data collected by a change sponsor and any analysis by the sponsor which has been completed by 27th 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. 
    2. For any ACP which has been implemented on or after 27th Feb 2020 PIR data collection and analysis should not be commenced until 1 December 2020 at which point the 12 months data collection period should commence. This date will be kept under review by the CAA and we will let you know if it changes. (any data collected between 1 March and 1 December 2020 cannot be used as part of a PIR data set).
    3. ACPs which have been implemented within 6 months prior to the 1st of March 2020, should extend their data collection period such that a full 12 months of data collection is achieved but discounting any data collected between 1 March and 1 December 2020. This should not extend beyond September 2021 unless agreed with the CAA. 
      Where an ACP has been implemented and more than 9 months PIR data collection has been achieved up to the 27th 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.


    This statement does not apply to the PIR of CAA Decision CAP 1678 – Farnborough Airspace change (see separate information on the Farnborough Airspace change webpage here) but applies to all other PIRs. Any Change sponsors with queries regarding the above should contact the CAA at Airspace.Policy@caa.co.uk. These requirements will be subject to review as required and no later than November 2020.

    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.

  • 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. 

    1. Organisation gathers data and operational feedback and information from stakeholders. 
    2. Organisation submits data to us. 
    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. 
    1. The organisation that requested the change can provide comments.
    2. The report is published on our website.