The UK Civil Aviation Authority (CAA) has published its Technical Concept of Operations outlining how Electronic Conspicuity (EC) will be used to integrate Beyond Visual Line of Sight (BVLOS) Unmanned Aircraft Systems (UAS) into non-segregated airspace alongside traditional crewed aircraft. The policy addresses the fundamental limitation of traditional “see-and-avoid” practices, which are generally ineffective for UAS because uncrewed aircraft are typically too small for crewed pilots to visually detect.

Equipage Requirements: Crewed vs. Uncrewed Aircraft

The CAA has proposed distinct technical requirements depending on whether an aircraft is crewed or uncrewed, and its operating speed.

Uncrewed Aircraft Systems (UAS): UAS operating BVLOS must emit a 978 MHz Universal Access Transceiver (UAT) ADS-B signal, functioning to DO-282B standards, with a Source Integrity Level (SIL) and System Design Assurance (SDA) of at least 1. Additionally, uncrewed systems are required to carry “ADS-B IN” receivers capable of detecting both 1090 MHz and 978 MHz signals. This receiving capability is mandatory because the legal responsibility for executing detect-and-avoid (DAA) procedures to prevent collisions with crewed aircraft rests with the remote pilot.

Crewed Aircraft: The requirements for crewed aircraft are determined by their speed and focus exclusively on broadcasting their position, rather than receiving data:

• Slower Aircraft (<140 knots IAS): Must broadcast using 1090 MHz ADS-B devices with an SIL and SDA of at least 1.
• Faster Aircraft (>140 knots IAS): Must use higher-performance equipment, specifically a Mode S transponder with ADS-B Extended Squitter functionality, operating with an SIL of 3 and an SDA of 2.

Crucially, the carriage of “ADS-B IN” equipment—the systems required to actually receive and display the locations of other aircraft, including UAS—will remain an optional, risk-based choice for crewed aircraft operators.

Sector Objections and Safety Concerns

A public consultation on these proposals received 808 responses, revealing significant objections from various airspace users regarding the integration of UAS and the required EC systems.

• Cost and Proportionality: The General Aviation (GA) community expressed strong opposition to the equipage rules. Many GA respondents argued that the financial burden of purchasing and installing mandatory EC devices should be borne by the UAS sector, which they view as the primary beneficiary of these airspace integration policies.
• Manoeuvrability: Of the respondents who opposed the equipage requirements for slower aircraft, 87.9% were glider, paraglider, hang glider, or paramotor pilots. These pilots argued that carrying EC equipment is impractical and fails to mitigate collision risks, as their unpowered aircraft lack the manoeuvrability required to evade oncoming traffic, including uncrewed systems.
• Mixed Equipage Risks: Because the CAA plans to keep “ADS-B IN” optional for crewed aircraft, safety advocates warned of a “mixed equipage” environment. Manned aircraft operating without receivers may have an incomplete picture of the airspace, potentially leading to unpredictable avoidance manoeuvres during close-proximity encounters with UAS.
• Technical Fragmentation and Distraction: Some respondents objected to UAS operating on the 978 MHz frequency, arguing it could fragment the current EC environment, which relies largely on 1090 MHz, thus reducing the likelihood of consistent detection. Furthermore, integrating low-power EC signals into existing Traffic Collision Avoidance Systems (TCAS) on crewed aircraft raised concerns about display clutter and excessive alerting, which could distract pilots.
• Privacy for UAS Operators: Objections were also raised by uncrewed aircraft operators. They noted that continuously broadcasting their locations could create privacy and security risks, particularly for sensitive UAS operations such as the delivery of medical supplies