London and London City Control Zones SVFR Weather Minima

The CAA is directed, as a priority, by the Transport Act 2000, Section 70, to “…exercise its air navigation functions so as to maintain a high standard of safety in the provision of air traffic services”. As the aviation industry changes through technological advancement, operational adjustment and shifting environmental considerations, the regulatory environment must also adapt to these changes to ensure that safety remains uncompromised. Regulatory change should ideally be proactive, anticipating the regulatory requirements in advance of industry-led change to ensure safety is maintained. This review of the weather minima applicable to SVFR operations within the London and London City Control Zones (the London CTRs) has been initiated by the CAA to ensure that a high standard of safety is maintained as the operating environment continues to evolve. A number of factors have been considered that relate to the current and future mix of operations within the SVFR environment of the London CTRs.

The increasing numbers of tall buildings and structures, considered to be those over 300ft in height, within the London CTRs complicates the ability of airspace users to navigate the landscape in conditions of low cloudbase while maintaining the required regulatory clearance from nearby obstructions. This also impacts the cockpit workload in conditions of poor visibility, with reduced time available to plan and execute a route to maintain clearance from obstructions once they are seen. The amount of time available to see and avoid other aircraft is also severely limited in the poorest visibility conditions allowed under the existing regulations, to the point they are considered not to offer a meaningful safety margin.

In line with existing and accepted practice, assessment of the suitability of in-flight weather for continued VFR / SVFR flight against required regulatory minima rests with the pilot-in-command. This also introduces a further possible source of error, either positive or negative, due to the accuracy of the assessment made by the pilot. There are numerous human factors that may influence the accuracy of the assessment made in-flight and this must form part of the consideration to define a suitable minimum visibility.

The final layer of complexity considered by this review is the introduction of Advanced Air Mobility (AAM) and new entrants into the urban aviation environment, The Future Flight Challenge. The Future Flight Vision Roadmap envisions Demonstration of AAM through 2024, followed by Industrialisation in 2026, Scaling through 2028 and leading to a Service-Based, fully integrated AAM ecosystem in 2030. The scale of this industry is forecast to be such that the regulatory environment must adapt to set the conditions to maintain the safety of all airspace users. The review must lead to an outcome that is robust and fit for purpose, that will facilitate the safe application of SVFR in the London CTRs, and that takes into account the anticipated growth in traffic density and increasing complexity of operation.

As a result, the CAA considers there to be a requirement for proactive regulatory change to increase the minima applied to the poorest weather conditions currently allowable for SVFR operations in the London CTRs. The existing weather minima for SVFR operations require pilots to remain Clear of Cloud with the Surface in Sight (COCSIS), and with a minimum in-flight visibility of either 1500m for fixed wing aircraft or 800m for helicopters. The CAA no longer considers these minima to be suitable to maintain the safety of aviation operations in this environment and propose to introduce a defined minimum cloudbase and an increased minimum visibility requirement for all aircraft types. The purpose of this review document is to articulate why the CAA believes this change is required and to request stakeholder feedback on the following SVFR weather minima proposal:

• Cloudbase 1000ft above ground level (agl);
• Visibility 3000m for all aircraft types;
• Applicable throughout the geographical area covered by the London and London City CTRs.