• 28 Jun 2024 11:29 AM
• 0

EASA and FAA Advance eVTOL Guidance

By VFS Staff
Vertiflite, July/August 2024

On June 10, the Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA) both announced progress in their efforts to streamline and standardize the certification of electric vertical takeoff and landing (eVTOL) aircraft and other new designs.

Each regulatory agency published notices that day outlining their new and harmonized guidance for these emerging aircraft types.

The proposed advisory circular (AC) 21.17-4 “Type Certification—Powered-lift,” published by the FAA, covers certification topics for powered-lift aircraft under the 21.17(b) framework. Specifics include flight data recorders; cockpit voice recorders; minimum safe speed for aircraft; and safety requirements for a buoyant, water-tight passenger cabin in case of a water landing.

In the AC, the FAA states that experience with “powered-lift applications” informed the agency’s proposed criteria for these emerging aircraft technologies. “This AC establishes a more efficient path in designating the type certification basis for certain powered-lift projects, as the FAA will not need to announce the criteria for each project in the Federal Register for notice and comment for those design,” the FAA stated, as it had done for Joby Aviation, Archer Aviation and others.

In concert with the AC, the FAA also published a draft policy statement, “Safety Continuum for Powered-Lift” (PS-AIR-21.17-01). This extends the agency’s philosophical approach to requiring higher safety levels of aircraft that expose higher numbers of the public to risk of injury or death (see “Vertically Speaking: FAA Rotorcraft Safety Continuum on Track,” Vertiflite, March/April 2018).

Four certification levels and corresponding safety requirements for powered-lift aircraft weighing up to 12,500 lb (5,700 kg) are outlined in the policy statement based on how many passengers the aircraft would carry for commercial operations, similar to the different levels for Part 23 normal category fixed-wing aircraft and Part 27 normal category helicopters. Existing Federal Aviation Regulations like Part 23 and Part 25, are intended to be used as bases for the Part 21.17(b) “special category” aircraft like powered-lift eVTOL aircraft.

The FAA notes that companies may seek certification for “essential performance” for aircraft or “increased performance,” the latter of which means the eVTOL is capable of “climbing to a safe altitude, on a flightpath clear of obstacles, and maintaining level flight to a planned destination or alternate landing.” These align somewhat with EASA’s approach for SC-VTOL with “basic” and “enhanced” categories, though a better analog is the FAA’s Category B and A helicopter performance, respectively.

Also on June 10, EASA published a second issue of its special condition for vertical takeoff and landing (SC-VTOL)-capable aircraft that updates regulatory guidance and increases harmonization with FAA standards.

EASA had already announced that it planned to increase the maximum certified takeoff mass from its previous 7,000-lb (3,175-kg) limit because of its requirements for redundancy (see “Helicopter Town Germany Hosts 49th ERF,” Vertiflite, Nov/Dec 2023). By settling on 12,500 lb, this weight limit is now the same as that of the FAA. The European agency states that this increase could “provide additional flexibility to type certificate applicants,” including “the installation of an increased battery capacity to enhance the aircraft mission.”

Provisions for survivability in the event of “ditching” or a water landing for eVTOLs are also part of the EASA updates that match more closely with FAA standards.

The European agency states that a further revision of the VTOL rules is planned “in the short term to implement further alignments” of regulation between itself and the FAA.

New rules for maintenance and technical training for electrical wiring are also among the updates to the EASA guidance. The high electrical power required for eVTOLs, EASA states, can “introduce new types of risks and may increase the likelihood and severity of known ones,” so new rules set by the agency seek “an adequate consideration” of electrical wiring in the certification process.

On June 13, at the conclusion of their annual joint safety conference, the two agencies “pledged to work together to meet the challenges of a fast-changing and evolving aviation industry and the increasing speed of development of future technologies.”