Maintenance, repair and overhaul (MRO) services will be one of many factors essential to the success of the eVTOL market. While maintaining air taxis on the scale that aeromobility proponents envision will be a challenge, industry figures highlight several advantages that eVTOLs have over other aircraft — from their inherently simpler designs to their potential for advanced prognostics.
As with any aircraft, an eVTOL is a highly advanced flying system that must comply with the highest safety standards, including the provision of adequate maintenance procedures, said Joerg Mueller, head of programme and strategy at Airbus Urban Mobility (AUM). However, while today’s civil helicopter operators are small and scattered, AUM envisions “large fleets of eVTOLs in major cities,” meaning MRO activity will need to scale up considerably.
“We need to develop the skills for doing this efficiently,” while helping customers and operators to do the same, Mueller told evtol.com.
There are also technological challenges to grapple with, he said. At some point eVTOLs are likely to be fully self-piloted, relying on onboard systems to ensure a safe landing even if serious malfunctions occur. This will demand a safe operating environment comprising unmanned traffic management and the appropriate physical and digital infrastructure.
While this is a certification issue, it also poses challenges for airworthiness maintenance procedures. However, Mueller said that air taxi services would operate “with a very well-defined mission and in a well-mastered and secured environment of vertiports and ground infrastructure,” which should reduce the types of incidents that require heavy repairs for traditional helicopters.
Airbus has developed its Vahana and CityAirbus eVTOLs as technology demonstrators, with no plans to produce them in quantities that would require a large-scale MRO approach. However, any future product would likely be operated in fleets that would require a tailored support and service approach, Mueller said, something the company will develop in parallel with its eVTOLs.
An all-electric propulsion system would require high-voltage electrical components, which would be a first for aviation, said Jonathan Hartman, disruptive technologies lead at Sikorsky Innovations. While such systems exist in the automotive space, they have not yet migrated to aircraft, and would demand unique MRO activities, procedures and insight “to effectively manage what will need to be developed as such systems mature.”
Pointing to Sikorsky’s experience in developing the Firefly all-electric technology demonstration program, Hartman said “the implications of a high-voltage electrical system permeate all operational aspects, from safety through component handling through lifecycle considerations.” However, this new technology — and the sensors that are often associated with it— will present new data-gathering opportunities, which could be used in MRO for predictive maintenance and other data-driven activities, Hartman added.
Sikorsky is “focused on sharing our vision for future urban mobility solutions,” Hartman said. While the helicopter manufacturer has not revealed any eVTOL development efforts, it “envisions adding an air mobility option to an integrated, multimodal transportation experience.”
Maintenance demands were key to the design of the Volocopter 2X, said a spokesperson for Volocopter — the only moving parts are the doors and the motors, meaning “maintenance should be very low.” The company will also use swappable battery packs to ensure the longest possible lifecycle and improve convenience, while it is looking into automated health checks and predictive maintenance, as many of its internal systems can monitor themselves through sensors.
The spokesperson also highlighted the use of carbon composite fiber for the platform’s fuselage; this is growing more common in aerospace and the auto industry, with most large MRO providers now offering specialized services for the material.
Aircraft manufacturers, MRO providers and flight operations will need to work closely together, the Volocopter spokesperson said. Maintenance and repair are still being discussed with regulators, specifically to define the types of licensing and regulation necessary for the work to be carried out on the platforms. Volocopter is generally keen to work with MRO specialists around the world, the spokesperson added. While it may make sense to conduct such efforts in-house in certain areas, when the platforms are rolled out globally “working with partners will provide a better and more cost-efficient service for our customers,” the spokesperson said.
A major driver for eVTOLs is the potential reduction in maintenance costs from the radical simplification of the system, said Mueller. For a typical small helicopter, the maintenance of the turbine engine, gearboxes, drive shafts, rotors and control systems can suck up over a quarter of direct operating costs. In eVTOLs these will be replaced by a very simple electrical drive train consisting of batteries, some power electronics, and electric motors. Additionally, Mueller said the health and usage of the drive train would be monitored with advanced data analytics and would be capable of detecting the smallest anomaly and predict when maintenance is needed.
The use of such data is key to the future of MRO, in eVTOL and for aircraft more broadly. Sikorsky today monitors the removal rates of different parts that contribute to grounded aircraft, tracking when parts need to be replaced, the reason they were replaced, and how long the process took. Hartman said this has been a common feature of the helicopter industry for some time through technology like health and usage monitoring systems (HUMS). Some of the latest technology in the area includes video analytics; this can identify failures to eliminate scheduled maintenance. It can identify things like cracks in blades, as well as corrosion behind panels.
A new space like eVTOL will have access to such technology from the beginning. “Efficiently predicting when and where a customer will need a specific part saves crucial time — and cost — of operating an aircraft,” he said.