Specific category flights

When flying under an operational declaration, the risk assessment is based on a standard scenario (STS). STS is one of the ways to operate a flight in the ‘specific’ category. All STSs define a specific scenario that can happen when flying an unmanned aircraft. There are currently two STS scenarios created by EASA: STS-01 and STS-02. The scenarios also list the general conditions that an operator must follow to ensure a legal and safe flight. This is the easiest way to operate in the ‘specific’ category, as the STS already includes a risk assessment, but you need to have C5 or C6 class marked unmanned aircraft to use this option. When you declare STS operations you need to familiarize yourself with European Commission implementing regulation 2019/947 annexes and make operations manual according to annex 5.

STS 01

STS02

An operational authorisation can be based on a PDRA (Predefined Risk Assessment). The PDRA tables are designed to facilitate applying for an operational authorisation and allow the operator to use a risk assessment already carried out when compiling the PDRA tables. PDRA is designed to allow more complex operations compared to STS and has been developed by the European Aviation Safety Agency (EASA) using conventional unmanned aircraft operations as an example of what can happen and how to avoid potential accidents and ensure safety.

To use the PDRA tables to apply for an operational authorisation, the operator must demonstrate that their activities meet all the requirements and conditions set out in the PDRA tables. While STS has a class label (C5-C6) on the unmanned aircraft, PDRA does not pose such a requirement. PDRA S01 and S02 use the same risk assessment table as the corresponding STS. PDRA, unlike STS, does not impose one specific method of operation but gives the operator more freedom to choose their operations.

is in reality a sort of checklist on how to develop the procedures that needs to be contained in the operator manual.

PDRA tables are available here:

PDRA classes

Two types of PDRA are distinguished: PDRA-S and PDRA-G. The former corresponds to the STS but allows the use of unmanned aircraft without a class label. The latter, however, includes risk assessments for the operation of other specific types of unmanned aircraft, which are more common in Europe.

More information about Predefined Risk Assessment (PDRA) 

SORA (Specific Operations Risk Assessment) is a specific risk assessment, which is carried out by methodically identifying the risks associated with the planned operation of an unmanned aircraft. For all flights that do not fall under STS or PDRA, a risk assessment in accordance with the SORA principles must be submitted to apply for an operational authorisation.
 

When must the SORA principles be followed when applying for an operational authorisation?

Although the STS and PDRA are also based on the SORA principles, they do not cover all flights. The operator must therefore carry out the SORA risk assessment procedure independently. This method is used for risk assessment when operations are more complex than in PDRA.

Briefly about SORA

The SORA method is a process in which the risks of complex operations are systematically assessed and potential vulnerabilities identified. Applicants determine in ten steps where, when and how they will carry out their operations without harming people or objects in the air or on the ground. The process should result in a detailed description of the planned operation and the associated risks as well as the means and activities to mitigate these risks.

The ten steps of SORA

Knowledge

What knowledge is needed for SORA? The risk assessment is carried out by the applicant (i.e. an institution or person wishing to carry out complex ‘specific’ category operations). Knowledge of aviation, as well as of conventional security-related systems in aviation, is essential. Depending on the complexity of the planned operation, the SORA method is a sophisticated process to follow, particularly where risk assessment is not a regular part of the applicant’s activities.

Support

If the applicant organisation is not competent to carry out a risk assessment, it can use the guidance material developed by EASA, which describes precisely how the SORA documentation should be completed. There are also companies that offer consultancy services for SORA applications.

Steps to obtain an operational authorisation

SORA application can be time-consuming. Conducting a risk assessment is a lengthy process, and so is the review of the application by the Estonian Transport Administration and, if necessary, giving feedback. It should therefore be taken into account that obtaining an operational authorisation can take a very long time.

What to consider when filing a SORA application?

Time. The applicant carries out a risk assessment and prepares the documents to be used for the operations. In addition, the operations require approval by the Estonian Transport Administration. Due to the volume of data that both the preparer and the reviewer have to handle, please allow several months for the preparation and validation of the SORA risk assessment.

Flexibility. The SORA method is carried out by the operator. Therefore, the operations must later comply with the assessment. It is up to the applicant to choose how extensive the risk assessment is and, therefore, how much freedom they will have in future operations. There is no need for a class-labelled unmanned aircraft, while insurance is required.

Complexity. For SORA risk assessment, the planned operations are assumed to be complex or highly complex. That is because the risk assessment does not cover pre-defined general common operations (for example, as exemplified in the PDRA tables). Depending on the complexity of the planned operations (SAIL 1 to 6), the requirements are more demanding and also require some basic knowledge of aviation.

Cost. The cost of the SORA assessment and review depends on the complexity of the planned operations and the quality of the documents originally submitted. Only fee that is fixed is state fee, but applicant will have more costs because of developing the needed documents. It is therefore difficult to set a fixed price.

The EU Regulation on unmanned aircraft has provided a new possibility for granting operational authorisations. The light UAS operator certificate or LUC is intended for light unmanned aircraft systems. LUC holders can confirm their flights themselves, i.e. they do not need to be authorised or approved by the Estonian Transport Administration. LUC holders must meet specific conditions, which are stricter than for ordinary operators. LUC requires a higher level of aviation knowledge and is intended for professional operators who regularly fly in similar conditions.

The conditions for obtaining an LUC are set out in Part C of the Annex to the European Commission Implementing Regulation (EU) 2019/947.

Flights where the risks are much higher than those in the ‘open’ or ‘specific’ categories fall within the ‘certified’ category. In addition to other stricter requirements, aircraft certification is required here. Examples of flights that fall under the ‘certified’ category include:

• flights over people;
• the transport of people;
• the carriage of dangerous goods that may pose a danger for third parties.

The ‘certified’ category requirements are under development by the EASA and Member States. Therefore currently authorisations for this category cannot be applied.