SAIL stands for Specific Assurance and Integrity Level. It is the main output of the risk part of a SORA: one level, from I to VI, that sums up how much confidence an authority needs in your operation.
The SAIL does not describe how dangerous your drone is. It sets how much you must demonstrate, and how robustly.
How it is determined
You look it up from two results: your final ground risk class and your residual air risk class.
| Final GRC | ARC-a | ARC-b | ARC-c | ARC-d |
|---|---|---|---|---|
| ≤ 2 | I | II | IV | VI |
| 3 | II | II | IV | VI |
| 4 | III | III | IV | VI |
| 5 | IV | IV | IV | VI |
| 6 | V | V | V | VI |
| 7 | VI | VI | VI | VI |
| > 7 | Certified category |
Notice the shape of that table. ARC-d means SAIL VI regardless of the ground risk. And above final GRC 7, the operation leaves SORA altogether and enters the certified category.
What it changes
The SAIL determines the level of robustness you need for each operational safety objective (OSO): the objectives covering matters such as aircraft design, maintenance, crew training and procedures.
In broad terms, a low SAIL allows much of the evidence to be self-declared. Higher levels ask for more rigorous evidence, and at the high end, for validation by a competent third party. Your costs and your timeline grow accordingly.
Why it pays to know your SAIL early
Your SAIL often results from decisions you can still change:
- The aircraft. A smaller or slower aircraft may land in a lower column of the ground risk table.
- The area. Moving a route away from denser areas, or controlling the ground area, reduces the iGRC.
- Mitigations. Sheltering, operational restrictions, ground observation and impact-reducing systems can each bring credit, provided you can prove them.
- The airspace. Lower altitude or staying away from aerodromes can reduce the air risk.
One level can make a large difference to the cost of an operation. So work it out before you buy the aircraft or sign the contract, not after.
Try it
Our SAIL estimator walks you through the published tables in about a minute. It gives an indication, not a determination. Only a full assessment accepted by your authority counts.