Joby Advances eVTOL Certification With Fog and Propulsion-Loss Test
What stands out most about the most recent flight test by Joby Aviation is not the spectacle, but rather the certification requirements for bringing powered-lift aircraft into the U.S. commercial market. On July 9, Joby said it has tested its sixth-generation eVTOL in conditions of dense fog and rain as well as simulation of the failure of one of its six propellers, after which pilots disabled another propeller to keep the balance and maintained hovering with four remaining propellers for around two minutes until vertical landing.
This is noteworthy because the FAA approach to certification of powered-lift aircraft is based on specific aircraft proof rather than general assumptions about the category of aircraft. The agency has stated that, at present, there are no type-certificated powered-lift aircraft in civil operations, which makes this type of aircraft certificated as a special category of airworthiness criteria specific to individual projects. Thus, testing in adverse weather conditions as well as propeller degradation simulation is not just a step forward in the process of achieving the milestone of successful flight. This is the very kind of systems-based proof that manufacturers need while progressing through the airworthiness flight-testing towards type certification.
Joby says that it has reached the last stage of FAA Type Certification Airworthiness flight tests required for commercial approval. As a rule, the overall FAA certification process includes design approval, conformity inspection, flight testing, and, eventually, production approval that allows for repeatable manufacturing. For eVTOL manufacturers, this implies that not only an aircraft itself but also the quality system behind it and the operating ecosystem must mature.
It is precisely at this point when the manufacture facilities of Joby come into play. The company describes Marina as a core hub for the assembly, testing, maintenance, and pilot training of its eVTOLs as well as a place for receiving in-house U.S.-manufactured components for final integration. According to Joby, the company designs and manufactures almost all parts of its aircraft itself excluding battery cells. Electric motors and power systems are manufactured in San Carlos, California, while propeller blades are manufactured in Dayton, Ohio and delivered to Marina.
For those familiar with the aerospace industry, this vertical integration is perhaps one of the most significant pieces of information. Manufacturing of major subsystems in-house can increase costs, but it provides greater control of configuration, validation, and manufacturing feedback loop while the design is still under development. In such a certification-intensive program, it is always critical how effectively design engineering, testing, inspection, and manufacturing quality processes are coordinated.
The production process of composite parts described by Joby at Marina facility supports this statement. Wing and fuselage structures go through carbon fiber layup on molds, high-temperature and high-pressure curing in ovens, non-destructive ultrasonic inspection for defects, painting, and then to adjacent final assembly line. This is a standard procedure of aerospace production, but, in the case of eVTOLs, it gains additional significance because of the necessity of repeatable build of the low-mass composite structures with distributed electric propulsion and tight acoustic parameters.
According to Joby, it conducts two to three test flights per day simulating various conditions, and its latest aircraft can be assembled within three months. The goal set by the company is reaching production of four aircraft per month next year. These figures should be considered not only in terms of production capacity but rather of industrial readiness. In the context of advanced air mobility, production rate makes sense only if every aircraft conforms to the certified design and can be maintained through appropriate maintenance and training programs.
It is the very framework developed by FAA that explains the importance of having an appropriate operating system. The agency has set up the temporary operating framework while collecting data for developing a permanent regulatory framework, which implies that pilot qualification, training, maintenance, and record-keeping require specific treatment for powered-lift aircraft. In other words, while flight testing is essential for certification, it is not enough on its own. The entry of aircraft into commercial service depends on simultaneous achievement of aircraft certification, manufacturing approval, pilot training, and operational procedures.
The Joby aircraft is described as carrying one pilot and four passengers and capable of vertical take-off and landing and wing-borne flight. However, the more important message behind this test is not the passenger comfort or convenient route marketing. It is the fact that Joby is using the adverse-weather operations, propulsion-loss handling, composite inspection, and in-house subsystem manufacturing to create a certifiable and manufacturable aircraft system.
Thus, for the U.S. eVTOL industry, it is the very criterion of success today. The competition is no longer about who is able to demonstrate the flight of their innovative aircraft. It is about who is able to turn flight test data, quality-controlled production, and operator-approved operating procedures into a certifiable civil aviation product. And the test of Joby in foggy and adverse conditions perfectly fits into this challenging new stage.
By Stephen Wallace – Editor for AMI’s aerospace integration and unmanned mobility coverage, focused on drone manufacturing, VTOL systems, autonomous networks, and air-ground mobility links.
