Free tool · specific category
SORA assistant for the specific category
Check whether your operation fits the open category or a standard scenario and, if not, work out the GRC, ARC and SAIL with the SORA 2.5 methodology applied by EASA, with an explanation of every step to prepare your AESA application.
What it does
Open category
Checks the limits of Article 4 of Regulation 2019/947 (under 25 kg, visual line of sight, 120 m, no assemblies or dangerous goods) and suggests the subcategory from the class marking.
Standard scenarios
Indicates whether the operation could fit STS-01 or STS-02, which only require a declaration to AESA.
SORA 2.5
Intrinsic GRC from the population density and size or speed table, M1(A), M1(B), M1(C) and M2 mitigations, initial ARC, SAIL and tactical mitigation robustness.
What to submit
Summary of the documents AESA usually asks for a specific category authorisation.
Guide: specific category and SORA
Open, specific and certified categories
Implementing Regulation (EU) 2019/947 classifies drone operations by risk. The open category covers the lowest-risk ones: aircraft under 25 kg, in visual line of sight, up to 120 m and not over assemblies of people. Anything beyond those limits is the specific category, which needs a declaration (standard scenarios) or an authorisation from the authority (in Spain, AESA) based on a risk assessment. The highest-risk operations fall into the certified category.
Standard scenarios (STS) and PDRAs
Standard scenarios STS-01 and STS-02 describe typical operations (in sight over a controlled area with class C5 drones, and beyond sight with observers in sparsely populated areas with class C6 drones) that are carried out with a declaration. EASA’s PDRAs are ready-made assessments for common operations that simplify the authorisation.
The SORA steps
- Ground risk (GRC): comes from the population density of the operational area and the aircraft’s size and speed. Mitigations (sheltering of people, operational restrictions, ground observation and impact reduction, for example with a parachute) reduce it according to their robustness.
- Air risk (ARC): depends on the airspace (controlled or not, airport environment, transponder zones), the height and whether you fly over urban or rural areas.
- SAIL: combines the final GRC and the ARC into a level from I to VI that sets how demanding the operational safety objectives (OSO) are.
- Containment and OSOs: requirements so the aircraft does not leave the operational volume, and demonstration of each objective with the robustness of the SAIL.
How to lower the SAIL
The most effective way is usually to reduce the ground risk: operate in a controlled or less populated ground area, at times with fewer people, with a smaller or slower aircraft, or with a certified parachute. In the air, flying below 150 m, away from airports and outside controlled airspace lowers the ARC.
To prepare the operation, check the point on the UAS zones map and rehearse the emergency procedures in the VTOL simulator with ArduPilot.
Other free tools
Questions
What is SORA?
JARUS’s Specific Operations Risk Assessment, which EASA uses as an acceptable means of compliance to authorise specific category operations. It assesses ground risk (GRC) and air risk (ARC), which give the SAIL.
Which SORA version does it use?
SORA 2.5, which EASA incorporated into the acceptable means of compliance for Article 11 of Regulation 2019/947 with Decision 2025/018/R. Check with AESA which version it accepts for your application.
What is the SAIL?
The Specific Assurance and Integrity Level, from I to VI. It determines the robustness with which the operational safety objectives (OSO) must be demonstrated: the higher the SAIL, the more demanding.
How do I know the population density?
With official density maps (for example, INE’s 1 km² population grid) over the operational area and its buffer. If the operation is in a controlled ground area, with no third parties, the GRC is the lowest.
Does it replace the official assessment?
No. It helps you understand where your operation falls and which mitigations improve it. The valid assessment is the one you submit to AESA with its justification, containment and OSOs.
What is the GRC?
The Ground Risk Class: it measures the risk of injuring people on the ground if the aircraft falls. It ranges from 1 to 7 within SORA; above that, the operation leaves SORA.
What is the ARC?
The Air Risk Class, from ARC-a to ARC-d: it measures the likelihood of encountering manned aviation. It sets the robustness of the tactical mitigations (TMPR).