The Future of Advanced Air Mobility

EASA Consults Industry on Special Condition Rules for Electric and Hybrid Propulsion Systems

The European Union Aviation Safety Agency (EASA) has launched a consultation on a proposed Special Condition rules covering the certification requirements for electric and/or hybrid propulsion systems (EHPS). The proposed new rules, published on January 27, are mainly for propulsion systems developed for new electric vertical takeoff and landing (eVTOL) designs, complimenting the Special Condition VTOL that the agency introduced for these aircraft in July 2019.

Once the Special Condition is established, following a consultation process that ends on March 3, 2020, EASA will propose acceptable means of compliance that can be applied for the certification of specific propulsion systems, taking account of the type of aircraft they are intended to support. In mid-February, the agency is expected to propose acceptable means of compliance for VTOL aircraft.

The proposed certification requirements will cover propulsion systems for manned or unmanned aircraft conducting normal or emergency operations. For now, they will not apply to EHPS for aircraft certified under CS-25 rules on the grounds that emission requirements for electric and hybrid propulsion systems have not yet been defined. The Special Condition will cover propulsion systems of any power rating and will address the interface between the propulsion unit and rotors and/or propellers. However, specifications for the propellers themselves will be covered by the separate CS-P rules.

The rules outline requirements for covering the design and construction of the EHPS themselves, as well as any associated systems and equipment, such as fuel, lubrication and cooling systems.