BVLOS Operations in Atypical Air Environment: Progress , Challenges, and What comes next
- Anne-Lise Scaillierez
- 19 hours ago
- 3 min read
Updated: 13 minutes ago
The UK Civil Aviation Authority has released the third edition of CAP 3040, its policy concept for enabling BVLOS operations in an Atypical Air Environment (AAE) on 27 November 2025.
What is an Atypical Air Environment?
Atypical Air Environment AAEs are volumes of airspace within which it can be reasonably anticipated that there will be a greatly reduced number of conventionally piloted aircraft due to the close proximity of specific ground infrastructure. AAE is not a new airspace class; it sits within existing airspace, and can exist in any type of airspace. Operators must follow all rules that apply to that class of airspace they are operating in.
Examples of AAE include:
within 100 ft of any buildings or structure;
within 50 ft of a permanent, above ground level, linear infrastructure (rail, road, powerline);
within the confines of private property at height not exceeding 50ft. For example, an industrial site where security personnel use an UA for perimeter inspection.
Why does Atypical Air Environment matter for BVLOS operations in the UK?
Currently, in the UK, there are 3 ways to operate beyond visual line of sight:
BVLOS with VM, beyond visual line of sight with visual mitigation
BVLOS in AAE Atypical Air Environment
BVLOS in segregated airspace. Either the airspace segregation already exists (operations in existing Temporary Danger Areas for example) or the operator must apply for a new airspace segregation through an airspace change proposal, a lengthy and challenging process that very few can afford.
Atypical Air Environment means that BVLOS is accessible without requiring airspace segregation nor a full Detect And Avoid system, because the probability of a mid-air collision is sufficiently low.
It is practical way to accumulate experience in BVLOS operations, further assess the actual frequency of crewed aircraft operating in your usual drone commercial operations environment, therefore better qualifying your real risk of a mid-air collision.
What type of user cases make sense in Atypical Air Environment?
Currently, user cases are mostly:
Inspection of linear infrastructures: railway lines, electric power lines
Inspection of windfarms
Security of a private perimeter with a Drone-in-a-box
Agriculture spraying and seeding
What are the remaining hurdles for operators?
AAE is progressing, but a few hurdles remain before it evolves from a policy concept, an experimental framework, to a commercially viable compliance pathway:
Strict limitations on what airspace qualifies as atypical
Flying BVLOS very close to the ground or infrastructure is operationally difficult. Terrain or obstacle strikes are a genuine risk. Height-keeping sensors may face interference or environmental limitations. Flight profiles must be calculated and programmed with great precision.
The operator must also provide detailed justification—and evidence—that the area truly qualifies as an AAE.
Uncertainty Around Electronic Conspicuity (EC)
The CAA’s position is that UAS should broadcast ADS-B Out at 978 MHz, and receive both 978 MHz and 1090 MHz (used by crewed aircraft).
However:
x/ Only a portion of crewed aircraft currently use ADS-B 1090 MHz.
x/ Drone ADS-B requires ICAO 24-bit addresses, which are scarce and prioritised for crewed aviation.
x/ At least one operator has gained an AAE OA but cannot operate due to the lack of a valid ADS-B address.
Until EC standards and allocations stabilise, this remains a bottleneck.
High Compliance Burden and Cost
To obtain an AAE OA, operators must prove that the airspace is genuinely atypical. CAP 3040 shows the level of granularity required. And because AAEs can be multi-sites but not generic permissions, each route or cluster of sites requires its own evidence package.
The amount of work and the application fee cost is viable for recurring operations or network-wide deployments—but less so for one-off projects.
Why we want to promote Atypical Air Environment?
AAE is one of the two realistic avenues for UK BVLOS expansion today (the other being VM). When the business case is strong, AAE can provide a distinct competitive advantage:
Lower per-mission cost once the compliance framework is established
Repeatability across similar sites
Operational efficiencies compared to VLOS or observer-based models
For operators who develop a mature, repeatable “AAE recipe,” the higher initial compliance cost can translate into lower long-term operational costs and a defensible market edge.
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