As drone operations continue to advance within Europe and internationally, safety factors are of high importance. The Specific Operations Risk Assessment (SORA) framework is a vital part of drone operations within the specific category to ensure that the highest safety standards are met.
Our technical examination of the SORA process focuses on the requirements and protocols necessary to secure an operational authorisation. It provides a thorough analysis of higher-risk operations and highlights key elements of the SORA authorisation process and how it can be understood in the context of obtaining a Light UAS Operator Certificate (LUC).
What is SORA?
SORA, or Specific Operations Risk Assessment, is a procedure designed to determine the safety considerations of a medium-risk drone operation. The process includes a detailed examination of potential threats such as collisions between UA and crewed aircraft, threats associated with a specific hazard such as physical obstacles, the aircraft's relevant design and the proposed operational mitigations such as flight planning and coordination with other airspace users/Air Traffic Control (ATC) for a specific UAS operation. The SORA process evaluates the risks systematically to determine the boundaries required for a safe operation.
There are several steps involved that are relevant to analysing the variables of drone operations, such as flying in specific areas or conditions. A SORA authorisation also outlines the appropriate measures to ensure the duration of the flight causes no harm to other aircraft, people or property.
By identifying and mitigating these factors, the SORA process aims to minimise any potential harm to enhance safe and reliable drone operations.
The Development of SORA
During his time as the leader of Joint Authorities for Rulemaking on Uncrewed Systems (JARUS) WG-6, Lorenzo Murzilli led the team in developing SORA. It was created by the working group due to the roadblocks that were delaying new technology from entering the commercial aviation market. This led JARUS WG-6 to strategise a framework to allow the authorisation process to run smoothly while adhering to the regulator's strict safety standards. This became known as the SORA methodology. Due to his leadership skills in the working group, Lorenzo Murzilli is often referred to as ‘The Father of SORA’ within the drone industry.
This led to a more widespread discussion of the system, which was soon to be used as European standard for Specific Category Operations. As part of EASA’s Aircrew Technical Body (TeB) from 2022 and JARUS from 2016-2023, Juanjo Sola continued developing SORA for the EU and its intermediate steps.
First launched by EASA in 2019, after the JARUS version 1.0 publication in 2017, the SORA methodology is a ten-step risk assessment procedure used to determine in which conditions a drone operation is safe within the Specific Category. A drone operation’s category can be determined based on operational risk, which takes into account various factors such as the drone’s weight, dimensions and flight altitude. SORA has since been implemented by EASA as a Means of Compliance throughout Europe and has been part of the framework for various countries internationally. Lorenzo’s training video as part of JARUS WG-6 is also referenced on EASA’s SORA page as supporting material.
What is the Specific Category?
There are three categories defined by EASA’s regulations for drone operations: open, specific and certified. The specific category allows drone operations of moderate risk to obtain authorisation with more operational flexibility while maintaining the required safety standards.
**Notes to be considered regarding the drone operation categories:
1. If the aircraft has a low-speed mode, the distance from people in subcategory A2 can be reduced to 5 m.
2. A declarative regimen can be applied within a low-risk operation in the specific category under a standard scenario umbrella.
To understand if a drone must be operated within the specific category, there are several main key factors to be considered:
Once the evaluation of the drone operation has been assessed and it has been categorised into the specific category, it will need to go through the SORA methodology process.
The SORA Methodology
The SORA Methodology, developed by JARUS, is a way to complete the Specific Operations Risk Assessment (SORA) to ensure the safe integration of drones into airspace and to consider potential risks to people or third parties on the ground. It identifies the level of the 2 specific risk classes: Ground Class Risk (GRC) and Air Class Risk (ACR).
The SORA authorisation process begins with an operator compiling a comprehensive risk assessment portfolio which will be submitted to the relevant national aviation authority (NAA) and includes several critical documents:
These documents form the foundation of the SORA process, which ensures that the relevant aviation authority can perform a structured evaluation of the proposed operations. Our consulting team at Murzilli Consulting can support with preparing the documents and aligning with the authority for the review process.
The NAA will then review all the documents and follow the 10 steps of the SORA Methodology to assess the operational risk level:
**Image is based on the EASA diagram**
- The Concept of Operations (ConOps) is the foundation of all activities. It outlines the relevant technical, operational and system information required to assess the risks associated with the intended operation of the UAS. This document needs to be given to the relevant authorities to grant the approval of the operation.
- The determination of Intrinsic Ground Risk Class (GRC) assesses the basic ground risk of operations. Low risk will be determined if the operations are in areas without people and high risk for populated areas.
- The Final Ground Risk Class (GRC) is determined after the risk mitigations (such as reducing the number of people at risk, having a parachute or an impact-limiting device and having a well-prepared Emergency Response Plan) put in place to avoid particular high-risk scenarios.
- The determination of the Initial Air Risk Class (ARC) assesses the basic air risk before each operation, including factors such as other airspace users and other flight rules (e.g. IFR or VFR) in various airspaces (e.g. controlled, uncontrolled, segregated, within safe distances from aerodromes).
- Application of Strategic Mitigations to Determine Residual Air Risk Class (ARC) is similar to step 3, where mitigations are used to define the air risk class. For example, coordinating with the manager of an aerodrome (including heliports) regarding height limitations or an operational restriction such as night exposure time.
- Tactical Mitigation Performance Requirements (TMPR) and Levels of Robustness classify mitigations that are performed in the air and consist of tactical mitigations to address the residual risk. For example, using an onboard collision avoidance system which will provide real-time traffic information and avoid other aircraft, would classify as tactical mitigations.
- Specific Assurance and Integrity Level (SAIL) and Operational Safety Objectives (OSO) Assignments are assessed by combining the final air risk class (ARC) with the final ground risk class (GRC). This determines the Specific Assurance and Integrity Level (SAIL) and which Operational Safety Objectives (OSOs) are relevant based on the SAIL.
- Identifies which Operational Safety Objectives (OSOs) are required based on the final SAIL.
9. Adjacent Area and Airspace Considerations mitigate the potential risk that can arise when control is lost during an operation, which could lead to entering unauthorised adjacent airspace and/or areas on the ground. Using the infographics below as a ground-risk example, in scenario 1, the operational area is an urban environment, therefore it is of higher risk, whereas in the 2nd scenario, the urban area is in the adjacent area, which makes it less risky. In cases where the population density is higher, the drone is required to have enhanced containment (the drone operates within a defined airspace volume).
- Comprehensive Safety Portfolio to compile all safety information after completing the SORA risk assessment.
To further assist with these steps, there are several training courses available on the SORA Methodology, including the DroneTalks SORA Fundamentals, featuring Lorenzo Murzilli.
Higher Risk Operations
Operations that are classified as SAIL III or IV are considered to be of higher risk and are specified as medium-risk within the SAIL levels because of their proximity to populated areas and complex operational environments. The technical specifications for SAIL III and IV operations are particularly strict and require several additional conditions and Means of Compliance (MoC). This is how they relate to the SORA steps:
🔸 Operators need to detail and justify the procedures and technologies used to comply with the safety standards using MoCs such as:
SORA Step #3
- MoC 2512 - M2 Parachute Medium Robustness/MoC 2512 - M2 Parachute High Robustness
SORA Step #6
- Special equipment relevant to the operation, such as advanced communication tools, anti-collision systems and emergency response technologies
SORA Step #8
- MoC OSO #5 - Functional Hazard Assessment (FHA) applies to UAS that operate without the need for Design Verification and specifically addresses systems such as uncrewed aircraft and their remote control equipment.
- MoC OSO #6 - C3 Link focuses on the Command and Control aspects (C2), which deals with the necessary hardware and software for communications between the control unit and uncrewed aircraft.
- MoC OSO #18 - Envelope Protection requires UAS operating in medium-risk environments to have systems in place to protect against pilot errors that could push the aircraft beyond its operational limits.
- MoC OSO #24 - Environment Conditions ensure that the UAS is designed to endure adverse environmental conditions such as temperature variations, humidity, vibrations and exposure to the elements (e.g. water and sand).
SORA Step #8
- Environmental conditions, notably noise pollution, remain a significant concern, affecting communities and ecosystems and necessitating effective noise management strategies
SORA Step #8 OSOs
- A Design Verification Report (DVR) is a critical document that confirms that a product meets its specific requirements through detailed design, testing and analysis
SORA Step #9
- MoC 2511 - Enhanced containment measures, such as physical and technological barriers to mitigate the risk of unintended flight outside of the operational area
To be Considered in a General Sense
- Public privacy concerns are escalating as surveillance technologies become more pervasive, highlighting the need for stringent regulations to protect individual privacy rights
SAIL V and VI are classified as high-risk SAIL levels and, in many cases, require an additional Type Certificate (TC). There has been a recent MoC publication intended for SAIL V and VI operations: MoC with Light-UAS.2510 Equipment, Systems and Installation. The MoC supports existing engineering and operational processes to ensure overall safety. The general Light-UAS.2510 rules are broadly applicable; however, more system-specific requirements, like redundancy or criticalities, take precedence and are based on and well-explained in SORA analysis or contemplated in any LUC obtained by the operator.
What is the Difference Between LUC and SORA Processes, and How are They Connected?
A Light UAS Operator Certificate (LUC) is an optional operational certificate which can only be authorised by the relevant National Aviation Authority (NAA). Operators who hold a LUC can access significant privileges such as the ability to perform an operation (under certain conditions) in the specific category without the need for an individual operational authorisation by the NAA. LUC operators are required to establish, implement and maintain a Safety Management System (SMS). The SMS needs to have an accountable manager and a separate safety manager to ensure compliance with standards as well as risk management processes, independent compliance monitoring, and effective communication and training strategies.
SORA is a risk assessment tool which evaluates an individual (precise or generic) operation in the specific category, in particular when the operation does not fit into a pre-defined category (e.g. EASA’s Standard Scenario 1 or 2). This process does not have ongoing operational privileges like the LUC and is used to evaluate the conditions of each operational use case to ensure all potential risks are meticulously analysed and mitigated.
Obtaining a LUC requires the operator to have significant prior experience and the ability to demonstrate their knowledge and adherence to best practices. The SORA process, which the operator can follow for those operations under its LUC privileges, relies more on individual operational limitations to maintain the operation’s highest level of safety.
How a Drone Consultancy Firm Can Help with SORA Authorisation
The SORA authorisation process requires a skilled level of experience and knowledge of the current regulations to run smoothly. Without this background, organisations can find themselves struggling to manoeuvre through the steps. This slows down the process, which will, in turn, extend the time and budget of the entire operation.
At Murzilli Consulting, we have defined our SORA process into 9 steps to ensure that the authorisation runs as quickly and as smoothly as possible.
Within this 9 step procedure, our drone consultants can ensure that all documentation will be thoroughly reviewed and all uncertain questions, such as the implementation of new technology, can be answered prior to the application with the regulator. With this process, Murzilli Consulting has successfully helped organisations achieve SAIL II authorisations and is currently working with several companies for SAIL III authorisation.
As of June 2024, there are very few SAIL III authorisations that have been approved throughout Europe. They are extremely complex and require additional support for the Operational Authorisation and Design Verification Process.
In order to obtain a SAIL III authorisation, it is recommended that the operator has extensive experience with:
🔸The drone unit
🔸All relevant procedures
🔸The rest of the crew members of the organisation
🔸And has previously successfully obtained authorisations for lower-risk operations (e.g. SAIL II)
🔸Additionally, the operator must be thoroughly familiar with aviation safety culture and adhere to safety standards, possessing significant experience in the sector
What are the Latest Updates on SORA 2.5?
As the JARUS members created the initial SORA 2.0 to be a living document, a newer version has been initiated. SORA 2.5 has been developed taking into account the feedback or ‘lessons learned’ that JARUS received since their first publication of SORA 2.0 in 2019.
The SORA 2.5 process has been refined into two new phases to minimise unnecessary iterations and enhance operational safety and efficiency.
🔸Phase I focuses on deriving safety requirements and proposing compliance methods and includes a preliminary assessment by the competent authority.
🔸Phase II verifies compliance with these requirements, ensuring all safety measures
are effective before full-scale operations commence.
**Source JARUS SORA 2.5 Main Body**
SORA 2.5 also provides guidance methodologies to determine whether a UAS operation is within visual line of sight (VLOS) or beyond visual line of sight (BVLOS), ensuring that pilots can maintain visual contact with their drones. It introduces new concepts essential for drone operation safety: Attitude Line of Sight (ALOS) and Detection Line of Sight (DLOS). ALOS defines the maximum distance at which a remote pilot can detect the position and orientation of the unmanned aircraft (UA), enabling control of its flight path. DLOS, on the other hand, specifies the distance at which other aircraft can be visually detected, allowing sufficient time for avoidance manoeuvres. The maximum possible VLOS distance between the remote pilot or observer and the UA is determined by the smaller value of ALOS and DLOS, ensuring precise and safe operations.
There are estimated to be 20 - 40 key changes from SORA 2.0 to SORA 2.5 such as significant updates to the table and calculation of the SORA Methodlogy Step #2 Intrinsic Ground Risk Class (iGRC) compared to SORA 2.0. Some other examples include the introduction of two additional classes for maximum UA characteristic dimension (20 m / 40 m); the replacement of typical kinetic energy with maximum speed or the acceptance of both quantitative and qualitative population density descriptions, with theoretical concepts which are detailed in Annex F. There are many more key changes from the SORA 2.5, which are available for public review here.
SORA 2.5 includes several reference infographics such as the example below, which highlights guidance for calculating adjacent area containment. The diagram reflects changes such as new UA classes based on maximum dimensions and updated population density considerations.
**Image is based on a diagram included in the JARUS SORA 2.5 Main Body**
The updated SORA 2.5 ensures that the SORA Methodology remains at the highest level of drone operational safety, which includes adapting to technological advancements and acknowledging operational feedback.
Would you like to know more about our complex support services for SORA authorisation? Email me for more information, and I will be happy to answer any questions: luis@murzilliconsulting.com
