UK SORA, Specific Operations Risk Assessment, is the CAA's framework for authorising drone operations that fall outside a standard predefined scenario like PDRA01. It scores an operation's ground risk and air risk separately, combines them into a single SAIL rating, and that rating sets exactly how much safety evidence the CAA expects before granting an Operational Authorisation. SORA itself is not an approval, it's the methodology behind one.
The Three Components
Ground Risk Class (GRC) scores the consequence of the aircraft losing control and striking someone on the ground, based on the aircraft's size, speed, the operating area and the population density beneath it. Air Risk Class (ARC), rated from ARC-a through ARC-d, scores the likelihood of encountering manned aircraft in the same airspace, based on airspace classification and typical traffic. Both scores can be brought down through mitigations, sheltering or a parachute system for GRC, electronic conspicuity or ATC coordination for ARC, before they're combined.
How SAIL Sets the Requirement
SAIL (Specific Assurance and Integrity Level), rated from I to VI, is what GRC and ARC combine into, and it's SAIL that actually drives the paperwork. Each SAIL level maps to a defined set of Operational Safety Objectives (OSOs), the higher the level, the more robust the evidence needed against each one, moving from minimal documentation at the lowest SAILs to a formal Safety Management System and independent validation at the highest. Two operations with wildly different aircraft or missions can land on the same SAIL level and face the same regulatory burden, because SAIL measures risk, not aircraft type.
When SORA Applies Instead of a PDRA
A PDRA (Predefined Risk Assessment), PDRA01 being the one most GVC and RPC-L1 holders operate under, already comes with its risk assessment built in, standard limits, standard requirements, no separate GRC/ARC/SAIL calculation needed. SORA becomes relevant once an operation sits outside those predefined limits, BVLOS work, flights over larger crowds, unusual aircraft configurations, or anything else a standard scenario doesn't cover. At that point the operator has to build the case themselves rather than rely on a template the CAA has already pre-approved.
Working Out the Risk Before Committing to an Application
The CAA's UK SORA-based Application Service lets an operator calculate their SAIL and containment level for free before submitting anything formally, payment only applies once the actual application goes in. That means a genuine cost figure or documentation burden is knowable in advance rather than discovered halfway through a paid application, worth doing early for any operation being scoped as BVLOS or otherwise outside PDRA01/PDRA02 limits.
Free Gifts Included
Free Gifts Included
Common Questions
No, it's the risk assessment methodology behind an Operational Authorisation, not the authorisation itself. Passing through SORA correctly is what gets an application approved, it isn't the approval.
Usually not. Work that fits inside PDRA01 or PDRA02's predefined limits doesn't need a separate GRC/ARC/SAIL calculation, those standard scenarios already carry their own pre-assessed risk profile.
Operations outside a predefined scenario's limits, most commonly BVLOS work, flights over larger numbers of people, or aircraft and operating profiles a PDRA doesn't cover.
No, SAIL reflects the combined ground and air risk of the operation, not the aircraft's size on its own. A small aircraft flown BVLOS over a populated area can land on a higher SAIL than a larger aircraft flown VLOS over open ground.
Yes, the CAA's UK SORA-based Application Service calculates GRC, ARC and SAIL free of charge, payment is only required once a formal application is submitted.
