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CAA Class G airspace use modelling

CAA Class G airspace use modelling

The CAA has commissioned a study into the aviation activity in Class G Airspace. The study is being carried out by the Airspace Safety Initiative group, which is a joint venture including civil, military and airspace service provider interests.

The BMAA has been involved in the project from the start and fully supports the initiative. Full details of the project are given in the text below from the ASI group. A major benefit from the BMAA point of view will be the better known traffic environment that will have to be taken into account by anyone proposing to establish controlled airspace. Proposers will have to take known activity into account and make sure that their proposals are mitigated to reduce the impact of such changes on Class G users, such as us.

The BMAA will continue to support the project and encourages all members to help by completing the survey form as asked.

ASI Introduction

Over time, the amount of Class G Airspace has been steadily reducing as the demand for controlled airspace has increased to meet the growth in commercial airline traffic, and the expansion of regional airports. Whilst the case for additional controlled airspace can be justified to meet increased IFR traffic, the impact such changes have on General Aviation users in adjacent Class G airspace is more difficult to quantify. Furthermore, when combined with growth or changes in patterns of activity by General Aviation users, a reduction in the amount of Class G airspace available can ultimately result in additional safety hazards (choke points, hot spots etc). If the consequential impact on Class G airspace users could be quantified, then sponsors of airspace change proposals and the CAA would have the means to take consideration of any consequential impact.

The fundamental problem here is the lack of reliable data relating to the level of activity in Class G airspace on which to base decisions. There is no universal requirement for radio or transponder carriage, and notwithstanding practical and technical issues, many users of Class G airspace have no requirement to “talk or squawk”. Consequently, radar pictures do not tell the whole story, and ATC units generally only know about the traffic that calls them.

The Airspace and Safety Initiative (ASI) has been established to investigate and tackle the major safety risks in UK airspace. It comprises representatives from CAA, NATS, MOD and general aviation organisations such as BGA, LAA, AOPA who work together to address common issues. In fulfilling its role, the ASI recognises the importance of being able to quantify the level of activity in Class G airspace, and has instigated a contract with defence and technology firm QinetiQ to deliver a 6 month long feasibility study into airspace modelling.


General aviation activity is highly diverse in nature (from paragliders to privately owned ex-military fighters) and variable in terms of the time when activity takes place (often dictated by weather). Whilst it is impossible to accurately predict the level of GA activity taking place at any given time, it is possible to understand the conditions that affect when each type of user may take to the skies, and the average amount of time that each user spends flying each year. By taking account of the rules and behavioural patterns governing of each type of user, it is possible (using computer modelling) to build up a picture of the activity that is expected to occur across the United Kingdom on a given day/time for a given set of conditions.

Benefits to Airspace Users

If the feasibility study is shown to be successful, a dedicated airspace modelling tool could (subject to funding) be developed covering the whole of UK Class G airspace. This will provide safety benefits to the general aviation community by:

· identifying confliction areas and ‘hotspots’, through quantification (in relative terms) of the level of activity in Class G airspace

· enabling flying organisations and individuals to use the results to support good airmanship by taking steps to avoid known ‘hot spots’ and choke points.

Further safety benefits will arise as a result of:

· Airspace change sponsors being able to assess the impact proposed airspace changes have on adjacent Class G airspace.

· Airspace regulators having the means to assess the impact of airspace restrictions, and so avoid creating ‘hot spots’ or choke points.

· Service providers being able to identify areas of increased risk and devise mitigation measures.

How you can help

The need for accurate data about the various activities that take place in Class G airspace is key to the success of this project, and this is where we need your support.

By completing the on-line survey at http://www.surveymonkey.com/s/G5Z9BNB we will start to build a picture about when and where flights are likely to occur, together with their duration. This information provided by different airspace users will be incorporated into the model to produce a ‘temperature chart’ showing the expected utilisation of airspace for all users across the feasibility study area.

The survey should not take more than 10 minutes to complete, and you will need your log book to hand. All information entered is non-attributable to individuals, and will only be used by the ASI for airspace modelling purposes.

Airspace modelling is recognised as an important tool that can enhance safety and ensure that sufficient Class G airspace remains available for the activities that operate within it. Please help contribute to this initiative by completing the survey.

On behalf of the ASI, thank you.

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