The European Union Aviation Safety Agency (EASA) has developed the Specific Operations Risk Assessment (SORA) methodology to enhance the safety of unmanned aircraft system (UAS) operations. This framework helps UAS operators quickly and effectively identify and mitigate risks associated with specific drone operations.

What Are the Risks in UAS Operations?

Risk refers to the likelihood (frequency over time) and severity (impact) of an event. In the context of drone operations, risks may include:

• Accidents or operational incidents
• Technical malfunctions
• System failures
• Damage to property
• Personal injuries
• Cybersecurity and data breaches

What Are Ground Risks in Drone Operations?

Ground risks involve potential damage or harm to people, property, or natural environments due to drone malfunctions or loss of control during a flight.

Key Ground Risks:

• Collision with people: This can occur in both urban and rural areas, with a higher risk in densely populated zones.
• Impact on infrastructure or buildings: A loss of control may lead to damage such as broken windows or structural harm.
• Collision with vehicles: If a drone operates near or above roads or railways, a malfunction could cause it to fall, posing a risk to moving vehicles.
• Mid-air collision with other drones or conventional aircraft: Debris from such incidents may result in additional hazards on the ground.

How Can These Risks Be Reduced?

To minimize ground risks, operators must apply a combination of technical and procedural (strategic) safety measures.

Technical Measures (Drone-Integrated Safety Systems):

• Emergency recovery solutions, such as parachutes or automated landing systems, which activate upon sudden abnormal movements.
• Geo-fencing technology, preventing drones from entering restricted airspace.
• Redundant control systems, ensuring backup solutions in case of failures.
• Real-time positioning and communication, using RTK GPS, 4G/5G connectivity, or similar technologies.

Operational and Strategic Measures (Pre-flight Planning and other ground-based risk mitigation):

• Thorough site assessment and risk evaluation before operations, including implementing local safety measures (e.g., warning signs).
• Use of certified equipment that meets regulatory standards.
• Comprehensive pilot training to handle emergency situations.
• Predefined operational procedures, including contingency and emergency response plans.

Why Is Risk Reduction Essential?

Drones, as technical devices, inherently carry operational risks. Effective risk mitigation is crucial to minimizing personal injury, property damage, and maintaining public trust in drone technology.

Justifying Risk Mitigation Measures

Operators must document and validate their risk mitigation strategies to comply with SORA requirements. This can include:

• Maintaining flight logs and incident reports
• Conducting technical inspections and tests (e.g., verifying redundant systems)
• Developing and enforcing standard operating procedures

Without proper documentation and compliance, an operating authorization cannot be granted. The application of the SORA methodology is a prerequisite for approval from aviation authorities. Operators must demonstrate that both ground and air risks are managed in accordance with legal and regulatory standards to secure authorization for their UAS operations.