## 3 Materials and Methods: The SORA Risk Analysis Methodology
### The SORA Process  
The SORA methodology provides a logical process for analyzing the proposed concept of operations (ConOps) and establishing an adequate level of confidence that the operation can be conducted with an acceptable level of risk. There are ten steps that support the SORA methodology, as shown in Figure 2. The process begins with the ConOps description, which provides the relevant technical, operational, and system information needed to assess the risk associated with the intended operation of the drone, both ground risk and air risk. Figure 1: General aspects of risk management from ISO 31000. The risk management process involves the systematic application of policies, procedures and practices to the activities of communicating and consulting, establishing the context and assessing, treating, monitoring, reviewing, recording and reporting risk. The ground risk class (GRC) is the intrinsic ground risk of the drone related to the risk of a person being struck by the drone (in the case of loss of drone control with a reasonable assumption of safety). To compute it, the applicant needs to identify the maximum drone characteristic dimension (e.g., wingspan for fixed wing, blade diameter for rotorcraft, maximum dimension for multicopters, etc.) and the knowledge of the intended operational scenario (VLOS or BVLOS; population density of the overflow areas). Intrinsic risks can be controlled and reduced by mitigations. The mitigations used to modify the intrinsic GRC have a direct effect on the safety objectives associated with a particular operation and, therefore, are important to ensure its robustness. The final determination of the GRC is based on the availability of these mitigations for operation. The air risk class (ARC), understood as the intrinsic risk of mid-air collision, determines the air risk category. Identification of the ARC must take into account the impact on other air traffic and air traffic management (the altitude of the operation; controlled versus uncontrolled airspace; aerodrome versus non-aerodrome environment; airspace over urban versus rural environment). The ARC may be lowered by applying strategic and tactical mitigation means (detect and avoid systems or alternate means) resulting in the residual ARC. Strategic conflict strategies will deal with the planning at a global level of the route that the drone must follow to execute the mission, while tactical conflict strategies will deal with reactive local maneuvers that are executed during the flight to fulfill certain functionalities, such as avoiding possible encounters with other aircraft. After determining the final GRC and residual ARC, it is now possible to derive the specific assurance and integrity levels (SAIL) associated with the proposed ConOps. The  
Figure 2: The SORA process adapted from [24] shows the ten steps that support the SORA methodology. SAIL represents the level of confidence that the operation will remain under control. On the other hand, the SAIL is also used to evaluate the defenses within the operation in the form of operational safety objectives (OSO) and to determine the associated level of robustness. These OSOs appear in the SORA as a list of objectives that have historically been used to ensure safe drone operations regarding technical issues, external systems supporting the operation, the effects of human errors, and the effects of adverse operating conditions. In this paper we address two different scenarios that are highly representative of mosquitoes-related operations. First, it is considered the case of an urban environment targeted for a STI mosquito program. Usually, large cities and their surroundings are immersed within the airspace associated with airports. Therefore, the operation is considered to be carried out in controlled airspace.