This document covers the broadest range of possible UAS configurations in the “Certified” category as defined by EASA regulation see Ref (4). This document covers unmanned aircraft configurations with no passengers or aircrew on board: casualties referred to within the analysis are third party casualties either on the ground or in the air. UAS includes the UA, the C2 link, the Control Station and any equipment to safely operate the UA.

This document is in line with ARP4761 philosophy. Considering that ARP4761 was primarily established for manned aircraft, a review of applicability to UAS of the various sections and Appendices of current draft ED-135/ARP4761A has been performed and is summarized in Appendix D. It shows that only some slight tailoring and adaptations are required in the following areas:

• Aircraft Level shall be replaced by UAS level

• Proposed functions should be slightly reviewed in the context of UAS

• UAS Failure Condition Classification (severity definition) is different, as stated in section 2.2 of this document.

This EUROCAE document provides a framework and common considerations specific to UAS that can be tailored to particular certification programmes.

This document aims to provide a UAS designer a generic high level “Basic FHA” for UAS, by considering differences between UAS/RPAS design / operation and conventional manned aircraft (Appendix C). For the purpose of providing illustrating examples, this document also provides an example of the application of this approach to specific UAS configurations (fixed wing and rotorcraft).

An FHA, as the starting point of the safety assessment process activities, is one of the central compliance evidence parts of the safety assessment process, supporting the certification and operational authorisation process in front of competent authority. This document, being generic in nature, provides a framework including a Basic FHA using a few assumptions and examples of specific configurations i.e. fixed wing (Chapter 4), rotorcraft (Chapter 5). In addition, Appendix E analyses the ATC voice communications function, illustrating some details specific in the case of UAS, as a starting point to enter into the FHA process for a specific UAS programme.

This proposed FHA baseline will concentrate on failure severity classifications, knowing that qualitative safety objectives and Functional Development Assurance levels are to be tied to specific configurations in the emerging airworthiness requirements. As a starting point, this document includes the Failure Condition Classification definitions in JARUS document AMC RPAS 1309 at issue 2, as the definitions applicable to UAS / RPAS are not currently in regulations. EASA UAS Certification Specifications are not due out before 2021.

In addition, it may also be used in the framework of Specific Category to meet the Operational Safety Objective OSO #5 of the SORA methodology, Annex E and Ref (5), when considering e.g. design or operational risk mitigations as compensating provisions.