Certification FrameWork VTOL
The VTOL Certification Framework is the regulatory and technical structure that defines how a vertical take-off and landing aircraft can be designed, justified, tested, and accepted by the aviation authority. In Europe, this logic is based on EASA, which issues the official rules, certification specifications, acceptable means of compliance, and guidance documents used as the basis for demonstration. For a project such as Mini-Bee, the challenge is not only to build an innovative VTOL aircraft, but to show that it can follow a credible path toward certification, safety, and operational approval.
In practical terms, a VTOL Certification Framework answers three essential questions: which category the aircraft belongs to, which rules apply to its systems and sub-systems, and which evidence must be produced to demonstrate compliance. In the case of Mini-Bee, the chosen logic is that of a small rotorcraft under CS-27, complemented by SC-VTOL-02 to address the specific features of a VTOL-capable aircraft, especially distributed lift, the hybrid thrust chain, the high-power electrical architecture, and the associated safety requirements.
High Level
The High Level corresponds to the strategic level of the certification framework. At this stage, the objective is to determine how the aircraft is classified within the EASA regulatory environment, which main texts apply, and what the overall certification philosophy will be. For a VTOL aircraft, this means identifying the main certification basis and then the complementary texts needed to cover the specific characteristics of the concept. In the case of Mini-Bee, this level leads to positioning the aircraft under CS-27 for its rotorcraft logic, with SC-VTOL-02 added to cover its vertical capability, distributed propulsion, and lift/thrust chain. It is also at the High Level that the maturity of the rules is assessed, along with possible gaps and links to other frameworks such as CS-29, CS-VLR, or certain AMC/GM approaches depending on the intended configuration.
Medium Level
The Medium Level corresponds to the compliance architecture of the systems and sub-systems. Once the aircraft category has been defined, it becomes necessary to specify which texts apply to each major technical function: engine, electric or hybrid propulsion, propellers or rotors, electrical installation, operational use, emissions, safety interfaces, equipment, and means of compliance. This is the level where the process moves from “what is the overall framework?” to “which certification reference applies to each building block?”. For a hybrid VTOL, this means linking the aircraft-level basis with CS-E for the engine, SC E-19 for electric or hybrid propulsion systems, CS-P for propulsive elements, CS-26 for certain operational airworthiness topics, AMC-20 for general compliance approaches, and CS-34 for emissions and environmental aspects. The Medium Level therefore transforms a broad regulatory vision into a clear map of the technical requirements applicable to each domain.
Low Level
The Low Level is the level of concrete demonstration. At this stage, the focus is no longer only on regulations or certification architecture, but on technical evidence. This includes detailed requirement allocation, safety analyses, design assumptions, system schematics, material files, control logic, bench tests, HIL/SIL simulations, robustness checks, electromagnetic compatibility, inspection procedures, test reports, and eventually representative-environment and flight evidence. In other words, the Low Level is where each requirement must be linked to an identifiable means of compliance: analysis, calculation, test, inspection, demonstration, or a combination of these. This is the level that gives an industrial project its real credibility, because it connects the certification intent to traceable and verifiable deliverables.
Why this framework is essential for a VTOL aircraft
A VTOL aircraft cannot be treated like a conventional aircraft based only on performance. Its real value depends on its ability to be certifiable, which means being able to demonstrate the safety of its design choices, the consistency of its propulsion architecture, the control of degraded modes, the robustness of its flight control system, and the traceability of its evidence. The VTOL Certification Framework is precisely what structures this process, from the high-level regulatory vision down to the detailed technical demonstrations. It is therefore not only a compliance framework, but also a design management tool.