The Federal Aviation Administration has released proposed guidance intended to help developers of electric air taxis better navigate the type-certification process and better understand how their aircraft will be evaluated by the regulator.
The agency, which released the guidance on 10 June, says they “will form the foundation for establishing certification criteria” for air taxis, also known as electric vertical take-off and landing (eVTOL) aircraft.
The FAA also said on 10 June it has reached agreements with Europe’s aviation regulator EASA pertaining to air taxi “performance requirements”, including those related to “safe flight and landing, handling qualities and single-point failures”.
“This… marks important progress in our effort to more closely align rulemaking and policy initiatives between the United States and the European Union,” the FAA says.
Due to unique flight characteristics, in-development air taxis do not fall neatly within the FAA’s existing certification categories.
For that reason, the agency intends to certificate such aircraft using standards found in certification rules pertaining to various other aircraft types. For instance, air taxis will be subject to some regulations specific to transport aircraft, and others specific to rotorcraft.
The process involves developers applying for type certificates, after which the FAA – at least until now – has responded by releasing “proposed airworthiness criteria” for public review. Those documents detail which regulations will apply.
The agency has already published proposed airworthiness criteria for two air taxis.
But the FAA says its new guidance, developed based on its experience with those two projects, sets criteria applicable to all eVTOLs that weigh 5,670kg (12,500lb) or less and carry six or fewer passengers.
“This establishes a more-efficient path in designating the type certification basis for certain powered-lift projects,” the agency says. “The FAA will not need to announce the criteria for each project in the Federal Register.”
The 52 pages of guidance define a broad range of standards, including those related cockpit voice and flight-data recorders, speeds, take-off performance, flight characteristics and stability. The document cites standards related to electric propulsion, engine-control systems, lubrication, vibration fire protection, vibration and durability.
For instance, it says air taxi energy systems must “be designed and arranged to provide independence between multiple energy-storage and supply systems, so that failure of any one component in one system will not result in loss of energy storage or supply of another system”.
The FAA is accepting public comment on the guidance for 60 days.
