As the eVTOL aircraft industry moves forwards towards offering commercial air-taxi services and first responder services, there is a growing need to define how these aircraft will be safe for use within an urban environment.

Visual representation of the Air-One® site with a Hyundai Motor Group eVTOL in the centre of Coventry. Image Copyright © Urban Air Port Ltd

We are already seeing announcements of planned mini airports for electric aircraft – with Lilium currently planning to launch 10 “Vertiports” in Florida (USA) and the first UK airport for electric aircraft now announced for Coventry, but on top of this there are various companies such as General Motors, Hyundai, Airbus and Aston-Martin currently looking at personal air taxis which could take-off and land from a roof top, or even your own driveway.

Taking accident data for helicopters as a starting point, the two highest causes of accidents are Loss of Control-Inflight and System (Powerplant) malfunction, with Low Altitude Operations and Collision cited as two additional causes for accidents.

eVTOL aircraft are designed to be flown at low altitude and the lack of any (or minimal) forward momentum during the vertical take-off and landing phases means that there will be no normal lift under any wings; and no rotational effect which is used by helicopters to control emergency descents.

The strain on pilots and motors may also be much higher than for normal aircraft, due to the use of the aircraft for short-hop journeys, with many take-offs and landings per day.  Bird-strike (where the aircraft collides with a bird) is also much more common at low altitude due to the greater nuimbers of birds in flight at lower levels.

At present there is no specific certification and safety requirements for eVTOL aircraft.  As with any aircraft, before they can be used in public service, they will need an airworthiness certificate to show how they meet the relevent safety standards.

The European Union Aviation Safety Agency (EASA) has been working on the certification of such aircraft since 2018 and Active VTOL Crash Prevention Limited is part of the team formulating the EUROCAE/EASA safety standards for eVTOL aircraft with specific responsibility for drafting new standards for both eVTOL Active Safety Systems and for Stroking Crashworthy seats.

As part of this, it has become apparent that current Emergency Descent Arrest Systems designed for fixed wing and rotary aircraft will not work when it comes to eVTOL aircraft and a new approach is required.

In particular, in the NASA Langley Research Center’s paper on “Challenges in Vehicle Safety and Occupant Protection for Autonomoud electric Vertical Take-Off and Landing (eVTOL) Vehicles” by Justin Littell; the author concluded that a Ballistic Recovery System should be a required piece of equipment but notes that existing systems do not advertise operation below 400 feet.

This is where the AVCP Zero-Zero Safety System comes to the rescue.