The Future of Advanced Air Mobility

FAA Expects First Advanced Air Mobility Aircraft to be Certified in 2021

The first of some 30 electric and hybrid-electric aircraft being developed for advanced air mobility (AAM) applications could achieve type certification this year, according to Jay Merkle, executive director of the FAA’s integration office for unmanned aircraft systems (UAS). He said that two or three other aircraft are close behind this front runner and that seven companies developing propulsion systems for this category of aircraft are also working with the U.S. agency on certification.

Speaking in the opening session of the Vertical Flight Society’s 8th Annual Electric VTOL Symposium on January 26, Merkle did not specify which type of aircraft is likely to be first. However, given that means of compliance for eVTOL designs are not yet fully defined by the FAA, it seems likely that it would be one of several fixed-wing eCTOL or eSTOL aircraft in development since their performance is a closer fit with the agency’s existing rules.

On the same day, Bye Aerospace announced that it has started building the first series-production example of its two-seat, all-electric eFlyer 2 aircraft. The company said that the first three production-conforming aircraft will be used to help complete certification under FAA’s existing Part 23 rules.

“These aircraft are priorities and, for now, we must work within the current regulatory structures,” Merkle said. “We’re not finding any obstacles yet, but as operations get more advanced there will be additional challenges.”

According to the FAA official, integrating the new aircraft into the available airspace and achieving equitable access to it alongside existing aircraft, including drones, will be one of the most significant challenges. “Traditional operators will not easily yield [their access to] the airspace and they [new AAM operators] will need to scale up operations in dense urban areas,” he commented, explaining that the current boundary between traffic management for unmanned and manned aircraft is around an altitude of 400 feet and that clear operating rules will need to be established for flights in both VFR and IFR conditions.

“We’re going to see higher levels of autonomy in manned aircraft moving into the UAS space,” he predicted. “[So far], there has not been sufficient emphasis on airworthiness in this [AAM] sector.”

Asked directly whether any of the new eVTOL aircraft will be ready to begin commercial operations in 2023, as some of the early market entrants intend, Merkle responded, “emphatically yes because the applicants that we’ve seen are close to the operations covered by [existing] Part 91 [rules], and so there is little need for waivers and exemptions.” He explained that his office is now handling the integration of all AAM aircraft, including those that will be piloted and carry passengers, as well as UAS.

Over and above the need to develop regulations to cover the technical complexity of some new aircraft, including increased automation and new means of propulsion, Merkle said that what he called “societal aversion to risk” is a significant issue to be resolved as part of the AAM integration strategy. “People are accustomed to seeing aircraft operate from airports and heliports and this will bring them into environments many have not seen before,” he commented.

The symposium also heard from NASA associate administrator Robert Pearce about how his agency is working in tandem with the FAA and the U.S. military to help build an AAM transportation system that he said could prove to be as large as existing modes of air transportation. NASA is working toward a timeline culminating in 2045 with a high degree of automated flight supporting complex, scalable, and dynamic operations by the new generation of aircraft, with much of its emphasis being on air traffic management.

In the nearer term, Peace indicated that NASA wants to be ready to conduct scaled urban demonstrations of AAM aircraft around 2028. He said these trials will likely be conducted on a similar basis to the unmanned traffic management trials the agency conducted with FAA approval in Reno, Nevada, and Corpus Christi, Texas, to evaluate challenges such as what happens when GPS service “drops out in urban canyons.”

Joby Aviation’s eVTOL prototype is set to begin developmental testing in April as part of NASA’s National Campaign program. The California-based company is also due to start the next phase of test flights before the end of January under the U.S. Air Force’s Agility Prime program to support the accelerated development of AAM vehicles for military applications.

Colonel Nathan Diller, director of the Air Force’s Afwerx group, which is responsible for Agility Prime, told the Symposium that flight testing will be conducted in multiple locations through partnerships with municipalities. He said that flights are set to begin in Ohio, where it has already installed a recharging station for electric aircraft and has plans to add a pair of flight simulators.

Joby is one of the first eVTOL aircraft companies to receive a government-funded contract to participate in Agility Prime development work. “We will be naming other companies soon,” Diller said.

The U.S. Army is also looking to enlist autonomous AAM aircraft into its portfolio, which already includes multiple UAS vehicles. UAS program manager Colonel Joseph Anderson explained that the service needs more operationally flexible unmanned aircraft to support roles such as mobile reconnaissance, surveillance, and target acquisition.

As part of its Future Tactical UAS program, the Army is looking for aircraft that will have an endurance of six or more hours, range of up to around 60 miles, and faster speeds than its current UAS, such as the Shadow. Anderson said that a key attribute will be that the new aircraft are “runway independent,” meaning they would need to be designed for vertical takeoff and landing operations. They will also need to have a “reduced size footprint,” and be able to be transported in the hold of a CH-47 helicopter.

The Army Requirements Oversight Council is expected to issue a Capabilities Development Document in the third quarter of 2021. This will detail all the requirements for the autonomous aircraft that the service intends to acquire.