Operational Risk Assessment Flashcards

In a drone operational risk assessment, what is meant by 'Ground Risk Class' (GRC)?

Answer: A measure of the expected severity of harm to people on the ground if the drone crashes

Ground Risk Class (GRC) is used in the SORA methodology to quantify the risk to people on the ground in the event of an uncontrolled landing or crash. It considers factors such as drone size, population density below the flight path, and whether the area is controlled (e.g., a cordoned-off site).

What is an 'operational volume' in the context of a SORA risk assessment?

Answer: The volume of airspace used during normal operations, defined by lateral and vertical boundaries including buffers

The operational volume is the three-dimensional airspace block within which the drone conducts its normal mission, including buffers for navigation uncertainty and contingency manoeuvres. It forms the basis for assessing both ground and air risk in the SORA process.

What is a 'contingency volume' in SORA and why is it important?

Answer: The additional airspace beyond the operational volume into which the drone may fly to execute a contingency procedure, such as an emergency landing

The contingency volume surrounds the operational volume and accounts for the space needed if the pilot must take emergency action — such as breaking off the mission and landing quickly. Ensuring there are no conflicting aircraft or hazards in the contingency volume is essential to safe operations.

How does population density affect the Ground Risk Class in a SORA assessment?

Answer: Higher population density increases the GRC because more people could be harmed if the drone crashes

SORA considers population density as a primary factor in GRC. Flying over densely populated urban areas creates higher ground risk than flying over uninhabited rural land, because the probability of a person being struck in the event of a crash is significantly greater.

What is a 'mitigating measure' in a drone operational risk assessment, and give an example?

Answer: An action or technical measure that reduces the likelihood or severity of an identified risk, e.g., cordoning off the area below the flight path to exclude uninvolved persons

Mitigating measures reduce either the probability of a hazard occurring or its consequence if it does. Establishing a controlled ground area (cordon) below the flight path is a common mitigation that reduces population exposure and can lower the effective GRC, enabling operations that would otherwise exceed open category limits.

What is the purpose of defining 'critical areas' in a pre-flight operational risk assessment?

Answer: To identify specific locations where failure would have the most severe consequences, requiring additional mitigation measures

Critical areas are locations within or adjacent to the operational area where a drone failure would have the most serious consequences — such as directly over a road, near a hospital, or above densely occupied buildings. Identifying these areas allows operators to plan routes that avoid or minimise exposure to the highest-consequence locations.