SORA FAQ: Top Questions Answered for UK Operators

SORA generates a lot of questions, especially for operators encountering the Specific Category for the first time. This FAQ answers the ones we see most often, in plain terms, with links to fuller explanations where helpful.

What does SORA stand for?

SORA stands for Specific Operations Risk Assessment. It is the structured methodology, developed by JARUS and referenced by the UK CAA in CAP 722, used to support applications for drone operations in the Specific Category.

When do I need a SORA?

You need a SORA when your operation falls outside the Open Category limits and no Pre-Defined Risk Assessment (PDRA) covers your scenario closely enough. If a PDRA fits, you generally use that simpler route instead.

What is the difference between GRC and ARC?

GRC (Ground Risk Class) measures the risk to people on the ground if the drone came down. ARC (Air Risk Class) measures the likelihood of a mid-air collision with manned aircraft. Both are assessed separately and then combined.

What is the SAIL?

SAIL (Specific Assurance and Integrity Level) is derived by combining the final GRC and residual ARC. It runs from I to VI and sets how robustly you must implement and prove your safety measures. A higher SAIL means more evidence and more rigorous verification.

Can I lower my SAIL?

Yes. The SAIL is influenced by the GRC and ARC, both of which can be reduced by mitigations. Shrinking the operational volume, adding a parachute, segregating airspace or fielding detect-and-avoid can each lower the risk and, with it, the SAIL.

What counts as a mitigation?

Ground-risk mitigations include reducing the number of people at risk (M1) and reducing the severity of an impact (M2). Air-risk mitigations are strategic (pre-flight restrictions and airspace segregation) and tactical (detect-and-avoid, observers). Each mitigation has a robustness level — low, medium or high — that determines the credit it earns.

What does "robustness" mean?

Robustness combines two things: integrity (the measure genuinely reduces the risk) and assurance (you can prove it does). A mitigation with strong evidence and, at higher levels, independent verification earns more credit than one merely asserted.

What are Operational Safety Objectives?

OSOs are the specific safety objectives — covering technical reliability, crew competence, procedures, maintenance and human factors — that you must meet. The SAIL determines which OSOs apply and at what robustness.

SORA or PDRA — how do I choose?

Check whether an existing PDRA matches your operation within its stated boundaries. If one does, use it: it is faster and more predictable. If none fits, build a full SORA. Sometimes a minor adjustment brings an operation within a PDRA's scope and saves considerable effort.

What changed in SORA 2.5?

SORA 2.5 refines the semantic model and terminology, clarifies the ground-risk and air-risk processes, and tightens how mitigations and OSOs are described. The core GRC/ARC/SAIL logic is unchanged. Always build against the edition the CAA currently references.

How long does a SORA take to prepare?

It varies enormously with the complexity and SAIL of the operation. A well-mitigated low-SAIL operation is far quicker than a high-SAIL BVLOS case requiring design-assurance evidence and independent verification. The Concept of Operations and the OSO evidence usually take the most time.

Do I need to be an engineer to write a SORA?

You need to understand the methodology and be able to produce credible evidence for your claims. Higher-SAIL operations demand more technical and engineering input, particularly for OSOs concerning system integrity and detect-and-avoid performance.

Where should I start?

Start by writing a precise Concept of Operations and identifying your intrinsic GRC and initial ARC. That tells you the SAIL you are working towards and, therefore, how much effort the rest of the case will require. From there, decide which mitigations bring the SAIL into a range you can realistically evidence.

A final word

SORA rewards honesty and clarity. Conservative, well-evidenced claims move through review far more smoothly than optimistic ones. And because the tables and expectations are refined between editions, always confirm the current requirements with the CAA's published guidance before you submit.