OSO 24 – UAS designed and qualified for adverse conditions
AMC1 Article 11 Annex E. Operational Safety Objective 24
CAA ORS9 Decision No. 46
Level of integrity
| Criterion | Not applicable | Medium (SAIL 3) | High (SAIL 4,5, 6) |
|---|---|---|---|
| Criterion | Not applicable |
OSO24.M.I |
OSO24.H.I |
Level of assurance
| Criterion | Not applicable | Medium (SAIL 3) | High (SAIL 4,5, 6) |
|---|---|---|---|
| Criterion | Not applicable |
OSO24.M.A |
OSO24.H.A |
| Alternative FTB method | Not applicable | OSO20.FT.M.A | OSO24.FT.M.A (SAIL IV only) |
Medium level of robustness (SAIL 3)
OSO24.M.I
The UAS must be designed to perform as intended in the environmental conditions defined in the flight manual or equivalent document.
OSO24.M.A
(a) The Applicant must provide evidence of compliance with the Integrity requirements.
(b) If compliance evidence is provided through simulation, the validity of the target environment used in the simulation must be justified.
(c) If (a), (b) and Integrity requirements are complied with through a SAIL mark certificate, the Applicant must demonstrate that the environmental conditions of the intended operation have been considered by the Designer.
OSO24.FT.M.A
The applicant must provide evidence of FTB flight hours proportionate to the risk/SAIL of the operation, meeting one of the set of conditions described in the FTB policy.
(a) Within the full operational scope/envelope of the intended operation, and
(b) Following the operational procedures and the remote crew training referred to in the OA application.
High level of robustness (SAIL 4, 5 and 6)
Lower robustness level requirements to be complied with:
• None
Additional requirements to be compiled with:
OSO24.H.I
The UAS must be developed to a standard or means of compliance acceptable to the CAA.
OSO24.H.A
The Applicant must provide evidence of compliance with the Integrity requirements, which will be assessed by the CAA. The CAA will validate continuing compliance through oversight.
OSO24.FT.H.A
The Applicant must comply with the requirements of OSO24FT.M.A (SAIL 4 only).
AMC.OSO24.H.I
Annex E – AMC 1 Integrity and assurance levels for the Operational Safety Objectives (OSO) paragraph 1.5 provides further information about proposing a standard as an AMC.
GM1 Article 11 Annex E. Operational Safety Objective 24
CAA ORS9 Decision No. 46
GM.OSO24
In order to comply with the integrity requirements of OSO24, the Applicant should determine:
• Credit may be taken for equipment’s environmental qualification testing, e.g. by answering the following questions:
o Is a Declaration of Design and Performance (DDP) available to the Applicant, stating the environmental qualification levels to which the equipment was tested?
o Did the environmental qualification tests follow a standard considered adequate by the CAA (e.g. RTCA DO-160 “Environmental Conditions and Test Procedures for Airborne Equipment”)?
o Are the environmental qualification tests appropriate and sufficient to cover all environmental conditions expected to be encountered during the operations?
o If the tests were not performed following a recognised standard, were the tests performed by an organisation or entity qualified or having experience in performing environmental type tests (e.g. RTCA DO-160)?
• Whether the suitability of the equipment to operate in the expected environmental conditions may be determined from either in-service experience or relevant test results?
• Any limitations which may affect the suitability of the equipment to operate in the expected environmental conditions.
The lowest integrity level should be considered where the UAS equipment only has achieved partial environmental qualification and/or a partial demonstration by similarity and/or where parts have no environmental qualification at all.
GM.OSO24.M.I
As an example, if a UAS is proposed to be operated in raining conditions, the UAS design is not required to comply with DO-160 waterproof requirements to demonstrate its suitability to operate in such conditions. The UAS may be operated in raining conditions, as long as they are representative of the environmental conditions which the UAS is designed for.
GM.OSO24.M.A
(a) Compliance evidence is typically provided through testing, analysis, simulation, inspection, design review or through operational experience.
(b) Designer data is found on the SAIL mark certificate.
GM.OSO.FT.24.M.A
The FTB method is an alternative means of compliance with OSO 24 assurance requirements.
Compliance with the requirement provides assurance that the operational procedures are adequate at the level corresponding to the SAIL being demonstrated by the FTB approach.
As an example, if the number of test cycles supporting the FTB flying hours is proportionate to the risk of a SAIL 3 operation (i.e. 3,000 FH), the assurance level for OSO 24 is satisfied at a medium level of robustness.