AAM Advance Air Mobility

IAS Innovative Aerial Service

the set of operations and/or services that are of benefit to the citizens and to the aviation market, and that are enabled by new airborne technologies; the operations and/or services include both the transportation of passengers and/or cargo and aerial operations (e.g. surveillance, inspections, mapping, telecommunications networking, etc.)

IAM Innovative air mobility

the safe, secure and sustainable air mobility of passengers and cargo enabled by new-generation technologies integrated into a multimodal transportation system;

UAM-urban air mobility 

the subset of IAM operations conducted in to, within or out of urban environments.

Propulsion systems

Rotorcraft have been mainly characterised by combustion engines (either turboshaft or piston engines). Electric engines are gradually being introduced in rotorcraft designs, rather as additional redundant propulsion system than as the main source of lift and thrust generation. On the contrary, aircraft with VTOL capability are expected to be equipped mainly with electric engines. Furthermore, the use of a combination of novel multiple lift and thrust units enables a higher degree of redundancy when appropriately dimensioned and designed.

Flight control systems

Excluding very few cases of helicopters equipped with fly-by-wire flight control systems, all rotorcraft are currently equipped with traditional flight controls (either boosted or not), with the addition of an augmented flight control system for stabilisation and long-term flight path control. Due to multiple lift/thrust units, advanced flight control systems (fly-by-wire or fly-by-light) form part of the design of VTOL aircraft in all current and newly started projects. In terms of design, this imposes new challenges with regard to achieving desired performance and safety standards, integrating suitable human–machine interface (HMI) and addressing human factors.

Moreover, it requires a completely different approach in terms of certification, with particular regard to the aircraft handling qualities, for defining both the requirements and the related acceptable means of compliance. Implicitly, new flight control philosophies for the simplified control of the aircraft through progressively increasing levels of automation will typically be implemented.

Energy systems

Novel energy sources (e.g. batteries of various chemistry, hydrogen, hybrid supplies) and their specific risks and limitations, including implications on operational use, require dedicated requirements.

Safety-of-design requirements

The intended use of high-volume operations over cities calls for dedicated requirements to ensure a commensurate safety level to prevent fatalities and protect third parties.

Environment

The noise profile may vary among the different aircraft designs, but noise levels are expected to be lower than those of rotorcraft.

Operations

The concept of operations for these novel aircraft has some peculiarities with respect to conventional rotorcraft and aeroplane operations, and has also an impact on their design and certification:

— piloting techniques with aircraft-specific control philosophies (advanced flight control systems often imply inceptors different than conventional cyclic/pedal/collective flight controls);

— reduced endurance will impose major constraints on operations, requiring aircraft to demonstrate equivalent levels of safety compared to the regulations and procedures used for helicopter operations;

— infrastructure (e.g. vertiports, firefighting, fire protection, high-voltage energy grid connection, security);

— ground handling (e.g. requirements on battery recharge/exchange, emergency response);

— operational procedures (e.g. navigation procedures, need to fly at low levels, flight rules, energy reserves, diversion, etc.);

— increasing levels of automation and pilot assistance systems leading to a different set of competencies and skills possessed by pilots.

— Strong link between design and operations

The safe, large-scale integration of these new aircraft into their intended operational environment (e.g. congested or hostile areas) requires synergies on the level of provisions and requirements distributed across several aviation domains (initial/continuing airworthiness

maintenance, air operations, flight crew licensing, rules of the air, air traffic management, aerodromes).

EASA had initially developed a definition for the initial airworthiness of ‘VTOL aircraft’ as provided in the EASA ‘Special Condition for VTOL and Means of Compliance’19, focusing on the lift generation design principle using multiple lift/thrust units (more than two), as these new architectures provide opportunities for increased safety through redundancy, but lead to challenges as explained and detailed above.

A corresponding definition is deemed necessary to cover the other regulatory domains, retaining the distinction drawn based on the lift generation design principle, but also explicitly defining a new category of aircraft distinct from aeroplanes and rotorcraft.

— VTOL-capable aircraft (VCA): a power-driven, heavier-than-air aircraft, other than aeroplane or rotorcraft, capable of performing vertical take-off and landing by means of lift and thrust units used to provide lift during take-off and landing.

To ensure coherence in the categorisation of the different aircraft designs, the definition of ‘rotorcraft’ is consequently amended to accommodate designs with up to two rotors for the generation of lift during the flight.

In performing the above assessment, EASA evaluated the possibility to adopt the existing ICAO definition of powered-lift20 aircraft as an alternative to VCA, but it was discarded as:

— the definition does not include all potential aircraft configurations that would be categorised as VCA, and in particular those that do not depend ‘on non-rotating airfoil(s) for lift during horizontal flight’ (e.g. thrust vectoring and direct lift);

— the ICAO framework for powered-lift aircraft is limited only to the requirements available in Annex 1 (applicable for flight crew licensing) while it lacks requirements for the remaining certification and operational domains.

There is a need to establish a comprehensive regulatory framework addressing the safety, security and environmental aspects of this new form of mobility of people and cargo by air in order to ensure its adequate acceptance and adoption by European citizens.

Some elements of this regulatory framework have already been established with the adoption of Commission Implementing Regulation (EU) 2019/94721, Commission Delegated Regulation (EU) 2019/94522, and Commission Implementing Regulation (EU) 2021/66423

The Opinion proposes amendments to several existing EU aviation regulations and the establishment of two new ones to address:

— the initial airworthiness of UAS subject to certification in accordance with Article 40 of Commission Delegated Regulation (EU) 2019/945;

— the continuing airworthiness of UAS subject to certification and which are operated in the ‘specific’ category; and

— the operational requirements applicable to manned VCA.