Bye Aerospace Nears eFlyer 2 Flight as FAA Options Expand
Bye Aerospace says its eFlyer 2 twin-seat electric airplane should make its first flight just weeks away assuming integration is on schedule. But for the U.S., the bigger issue for the electric trainer is whether a domestic electric airplane can enter service faster by shifting its certification approach from the FAA’s traditional Part 23 route to the recently introduced Part 22 standard for light-sport aircraft.
It matters because the eFlyer 2 is not a plug-in conversion kit for a legacy airframe. The eFlyer 2 is a fully designed airplane featuring a composite airframe, a dual-voltage electric system, and a list of suppliers that look like a clean sheet aircraft development rather than an airframe conversion project. Final assembly, integration, and system testing are currently underway at Bye Aerospace’s Centennial Airport facility in Aurora, Colorado. Fuselage and wing structural tests have been completed, while integration of flight controls, brakes, and instrument panel is finished as well.
The electric propulsion architecture reveals what really counts in the eFlyer 2 design. Bye says the airplane is wired to include both a 28V low voltage system for avionics and lighting and a 800V high-voltage propulsion system, which includes a 125kW Safran ENGINeUS 100B1 electric motor. Cockpit is fitted with the Garmin G500 TXi touchscreen avionics suite. Around that core configuration, the airplane relies on a supply chain that is quite recognizable, consisting of Toray Composite Materials for composites, Sensenich Propellers in Florida for propellers, M4 Engineering for composite doors, Flying S Manufacturing for the composite tail assembly, and Risse Racing for nose gear and motor mounts. Bye Aerospace says Magnix batteries will power the airplane.
Design-wise, Bye Aerospace relied on aerodynamics and efficient battery management to squeeze sufficient training endurance out of existing battery technology. Specifically, the manufacturer says the aircraft was developed with Siemens software and lightweight composite materials to deliver two hours of endurance plus a 30-minute reserve. However, CEO Roderick Zastrow stated that 1.7 hours of endurance will be regarded as good enough result and added that the aircraft requires 30 minutes of charging time between flights.
Consequently, the eFlyer 2 aircraft must be seen primarily as a cycle aircraft, i.e. capable of repeated launch-training-recovery-charging cycle without maintenance issues. Bye Aerospace sees the aircraft competing with other training aircraft such as the Cessna 172 and Piper Archer airplanes, while adding electric competition such as Pipistrel’s certificated Velis Electro and BRM Aero’s Bristell B23 Energic aircraft.
Certification-wise, the situation is quite clear. Bye Aerospace filed a design and certification document in 2018 and has been working on FAA certification under Part 23 Amendment 64 performance-based rules issued in 2016 by FAA. According to the manufacturer, it completed almost all the necessary steps except that it might take up to two additional years to complete certification work. As it often happens in new aircraft development, it may take a while to collect all the necessary information for the regulatory authority and prepare a documented case. However, there is an additional route that could potentially cut off that time significantly.
Specifically, Part 22 regulations for light sport aircraft are coming into force in July 2021. According to Bye Aerospace, switching to the new rules might shave some two years from its certification effort allowing to achieve certification and first aircraft deliveries within 10 months. The reason for that is quite straightforward according to Bye Aerospace, Part 22 allows it to certify the aircraft with the existing documentation and test results in hand and start production.
The latter statement corresponds quite well with the new light-sport aircraft philosophy as presented by FAA when developing a regulation. Namely, FAA described the transition from category-based certification rules to the performance-based standard as a move from strict aircraft categorization based on characteristics to the approach focusing on compliance with accepted standards. While Part 22 rules do not represent a lower standard of safety, they provide potentially more appropriate regulatory framework for a relatively innovative aircraft design.
Of course, nothing is certain until now. For the time being, Bye Aerospace says it prefers to stick to the traditional Part 23 certification route while maintaining the Part 22 option. This is the rational position for the manufacturer while Part 23 remains the more recognized standard for a normal category aircraft, Part 22 could prove itself as a fast track if the airplane is well suited to the new certification process.
In any case, first flight of the eFlyer 2 is expected in the upcoming weeks. However, the flight will be just a step forward. The question is whether Bye Aerospace can finish necessary design and certification work and switch into full-scale production before orders dry up because of lack of availability.
According to Bye Aerospace, the company has agreements for delivering 1,124 eFlyer 2 and eFlyer 4 aircraft, including such customers as KLM Flight Academy, SkyBorne Airline Academy, Spartan College of Aeronautics and Technology, and Flex Air. Such numbers speak for themselves, but still, those deals are not as significant as such critical factors as certification standard, production readiness, charging, maintainability, and dispatch reliability.
As a result, the eFlyer 2 aircraft is moving towards the crucial test: certification, production readiness, and entry into service in real-world training environment. For Bye Aerospace, the key task is to reconcile its composite airframe, electric propulsion, and appropriate FAA certification pathway without pushing the schedule to limits.
By David Whitaker — Associate editor for AMI’s aerospace and drone systems desk, translating flight systems, aircraft programs, spaceflight, and UAV developments into accessible technical stories.
