The electric ENGINeUS 100 series is starting with the B1 model now certified, initially planned for installation on a two-seater aircraft. The aim is to extend the series to a greater power range (from 89 KW to 180 KW), a baseline to allow for wider application in up to 19-seater aircraft.
For EASA, the certification process in this case brought learnings that can be applied to further propulsion projects in the future.
“This was a fascinating project for EASA, and the first test of our Special Condition designed for the certification of hybrid and all-electric propulsion,” said Rachel Daeschler, EASA Certification Director. “EASA is fully committed to supporting the development and certification of propulsion technologies aimed at decarbonising aviation. We congratulate Safran for this key achievement, which is paving the way for the electrification of aviation, for small airplanes and beyond.”
Back in 2017, EASA initiated discussions on regulation evaluation for a wide spectrum of innovative propulsion systems. A number of requests for the type certification of novel designs were coming to EASA, mostly for General Aviation and vertical take-off and landing (VTOL) aircraft. The manufacturers variously had the ambition to enable Urban Air Mobility (UAM) or create new solutions for Regional Air Mobility (RAM). Electric or hybrid engines, as well as the diversity of new propulsion system architectures proposed, were not foreseen when the specifications for the conventional thermal engines were originally developed decades ago. A new electric engine could not therefore be certified directly against these specifications.
Definition of Special Condition SC E-19
To fill this gap, EASA developed what is known as a Special Condition (SC). The objective was to allow clearly needed innovation for sustainability, while ensuring the same safety record as today’s thermal engines. The aim was to support innovative propulsion certification with a unique performance-based requirement applicable to both aircraft and engine certification applications, so as to guarantee consistency from the outset.
SC E-19 for the certification of hybrid and/or electric propulsion was published in April 2021. It was then implemented as the certification standard for VTOL applications and to the first propulsion type certificate application from a new company associated with a larger well-known group, Safran Electrical & Power.
This first engine application marked the start of an enriching common journey for EASA as a regulator and the manufacturer: it enabled EASA to shape the future of propulsion certification and create further detailed guidance to accompany manufacturers on the path to achieving more sustainable aviation at a larger scale.
Certifying ENGINeUS 100 according to SC E-19
Close cooperation with the regulator was required to define appropriate analysis and tests that proved the design is compliant.
In this case, the engine design had several novelties that entailed developing new means of compliance. As examples of the extent of its novelty, the ENGINeUS engine uses new power modules and integrates the power electronics directly into an air-cooled engine.
Safran Electrical & Power proved to be very agile and creative in designing tests that were able to demonstrate the safety of an electric engine, where the safety challenges faced are very different.
“As one example, the minimisation of fire risk had to be rethought in its entirety,” said Régis Rossotto, project manager from the EASA side. “In contrast to combustion engine for which the risk of fire arises from the ignition of flammable fluids, in an electric engine, that risk comes from the use of high voltage and electrical arcing. A worst-case scenario was defined and tested, and mitigations were put in place to allow a pilot to land safely if such a scenario arose.”
Such topics required very close collaboration not only with the EASA flight test and powerplant experts but also with Diamond Aircraft Industries GmbH, the airframe manufacturer that is the initial customer for the ENGINeUS.
As a result of the strong cooperation between Safran and EASA, the certification of ENGINeUS 100B1 required a similar time investment as for a rotorcraft turboshaft engine: less than 2 years. In parallel to the engine certification, the engine racked up more than 100 flight hours on prototype aeroplanes.
Background
In June 2020, EASA certified the Pipistrel Velis Electro, awarding the first type certificate to a fully electric aircraft and its engine. This was however certified as a CS-LSA category aircraft or ‘Light Sport Aeroplane’.
Tags: Rachel Daeschler, EASA, Safran
