Well, instinctively the short answer seems to be "No! Why would we ever do that?". However, as attendees of the Airborne Conflict Safety Forum that took place on 10-11 June at EUROCONTROL HQ discovered, the answer might not be that straightforward.
Whether to reduce fuel costs or give access to specific airports, commercial flights operating in uncontrolled airspace is a reality. Although not a common occurrence today, new modes of operations will lead pilots to venture outside the familiar boundaries of controlled airspace. Several factors are expected to drive that increase in commercial flights sharing airspace with VFR traffic: development of new routes, focus on fuel-efficient flight profiles, faster adoption of free-routing, etc. Advances in navigation (such as PBN applications) are also expected to boost the number of IFR flights in class G airspace, for example by opening up instrument-approach access to new aerodromes and creating user-specific IFR routes to transition through uncontrolled airspace.
The safety eco-system that commercial pilots are accustomed to in controlled airspace can be disrupted by operating in a mixed environment: mixed-aircraft performance, mixed-avionics equipage, mixed-ATC services, mixed-airspace users training...
With this change comes the risk that airborne and ground safety nets might behave differently. For example, how compatible are the various Airborne Collision Avoidance Systems such as TCAS, PCAS or FLARM?
ACAS applications undoubtedly provide some degree of protection against mid-air collisions, assuming other aircraft are transponder-equipped, which is not always the case in uncontrolled airspace. Also Flight Information Services and Traffic Information Services might be available to support airspace users, although evidently no ATC clearances can be provided to support safe separations. Crucially, in this scenario the responsibility for maintaining separation between aircraft now lies with the pilot rather than with the controller. This needs to be understood by all airspace users operating in uncontrolled airspace, particularly those unused to Class G. See & Avoid becomes the primary safety barrier.
The pressure to push costs down and reduce the environmental impact of aviation has never been so intense. This puts additional pressure on the airspace as more efficient routings (including climbs and descents) are requested by users normally afforded the protection of controlled airspace. The issues associated with flying commercial aircraft alongside VFR traffic are therefore unlikely to go away and need serious consideration by the industry.
As often in complex situations, the answer lies in a combination of elements. Preliminary findings from the Airborne Conflict Safety Forum give a few pointers:
- Airspace design is key. Too often, outdated airspace structures originally designed for the needs of several decades ago and subject to updates over time are still in use, resulting in a complex and patchy layout – we need a fresh look at it.
- Refocus training and awareness campaigns for all stakeholders, to better identify airspace classes, remind people of the implications of operating in these classes and clarify responsibilities between airspace users and ATC.
- Get a better understanding of interactions between safety nets to maximise their efficiency and ensure incompatibilities are addressed.
Sadly there is no one-size-fits-all solution as each stakeholder has its own priorities and each environment its own constraints. One thing is for certain though: in our highly integrated ATM system, we cannot afford to address this issue from a single perspective only. A total system approach, taking into account airspace design, technological and human factor aspects is essential. Finding the right compromise between safety, efficiency and airspace accessibility will be a balancing act that will require involvements from all aviation stakeholders.
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