What can be learned from the ARCHER airworthiness criteria ?
The FAA recently issued a final airworthiness criteria for a special class aircraft. This groundbreaking event has been reviewed by MSN; see below. The FEDERAL REGISTER notice is 34 pages of three columns with 12 pica. The text is filled with comments from the public on the merits of what the FAA should/must test/assess before issuing an airworthiness certificate to ARCHER for its Midnight. Over half of the pages (17) are devoted to ~19,000 pages of discussion on the merits of the FAA’s required proof.
This is not the first FAA definition of the airworthiness criteria for a powered-lift vehicle on March 8,2024 — Airworthiness Criteria: Special Class Airworthiness Criteria for the Joby Aero, Inc. Model JAS4-1 Powered-Lift.
AVIATION INNOVATION is challenging the FAA in its aircraft certification duty. Historically, actually experientially, novel introductions to flight were not radically different from existing structures, wings, controls, power, etc. provided data from which the industry and government engineers could reliably extrapolate to assess the airworthiness of the dynamic changes.
Here are a few of the highlights from the ARCHER criteria:
“…On March 30, 2022, Archer applied for a type certificate for the Model M001 POWERED-LIFT. The Archer Model M001 powered-lift has a maximum gross takeoff weight of 6,500 lbs. and is capable of carrying a pilot and four passengers. The aircraft has a high-wing and V-tail 1 configuration with fixed tricycle landing gear. The aircraft uses 12 electric engines powered by onboard batteries for propulsion instead of conventional air and fuel combustion. Six engines with five-bladed variable[1]pitch propellers are mounted on the forward edge of the main wing, three to each side, which are capable of tilting to provide both vertical and forward thrust. The other six electric engines drive two-bladed fixed-pitch propellers and are mounted on the aft edge of the main wing, three to each side; they are fixed in place to provide only vertical thrust. The aft-mounted engines operate only during thrust-borne or semi-thrust borne flight; in wing-borne forward flight, these engines are switched off and the propellers are faired in line with the aircraft fuselage. The aircraft structure and propellers are constructed of composite materials. The Archer Model M001 powered-lift is intended to be used for Title 14, Code of Federal Regulations (14 CFR) parts 91 and 135 operations, with a single pilot onboard, under visual flight rules (VFR)…
“Because the FAA has not yet established powered-lift airworthiness standards in 14 CFR, the FAA type certificates powered-lift as special class aircraft. Under the procedures in § 21.17(b), the airworthiness requirements for special class aircraft, including the engines and propellers installed thereon, are the portions of the requirements in 14 CFR parts 23, 25, 27, 29, 31, 33, and 35 found by the FAA to be appropriate and applicable to the specific type design and any other airworthiness criteria found by the FAA to provide an equivalent level of safety to the existing standards. These final airworthiness criteria announce the applicable regulations and other airworthiness criteria developed, under § 21.17(b), for type certification of the Model M001 powered-lift.
…
“Technical Areas in General Order of the Airworthiness Criteria Sections
- Aircraft Performance, Handling, and Control
- Icing
- Structural Design Loads
- Structures
- Aeroelasticity & Aeromechanical Stability
- Flight Controls
- Occupant System Design Protection
- Bird Strike
- Fire and High Energy Protection
- Propulsion Safety and Integration
- System Safety
- Lightning Protection
- Flightcrew Interface
- Electric Engines
The application of these criteria to the Midnight (and the JAS4-1) will be a test of the company’s engineering team and the FAA certification staff. How much data, how many iterations of the tests, what resubmissions of the analytical tables will be required and what unpredicted issues are found plus how they can be resolved—THAT’S THE THINGS THAT WILL CAPTURE THE CONFIDENCE OF THE FAA.
The path through this ever-evolving standards for these aircraft of the future, the immediate future, benefits from an SME who has walked through the regulatory maze.
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Archer closes in on FAA approval for Midnight eVTOL aircraft
Story by Noah Bovenizer
Air taxi manufacturer ARCHER AVIATION has become the second company to reach the final airworthiness criteria stage of Federal Aviation Administration (FAA) certification for its electric vertical takeoff and landing (eVTOL) aircraft.
The US-based company announced the milestone after the regulator published the criteria for public inspection, allowing Archer to work on final certification and testing approvals for its Midnight model.
BILLY NOLEN, Archer’s chief regulatory affairs officer, said: “Midnight is one giant step closer to taking passengers into the sky in the coming years in the U.S. The final airworthiness criteria for Midnight is an important step on our journey to make electric flying taxis an everyday reality.”
The FAA’s criteria publication comes as Archer continues construction of its first fleet of Midnight aircraft that will be used in “for credit” piloted flight testing later this year.
While the company has already conducted multiple tests of its eVTOL aircraft, the new models will be the first that conform to the airworthiness criteria, meaning tests on these vehicles will count towards the flight hours needed to achieve FAA certification.
Archer’s CEO recently revealed that it had conducted more than 100 flights in Q1 of 2024 and was on track to achieve its goal of 400 flights in the full year.
As it works towards certification Archer has been rapidly growing its operations, building two factories in the states of California[1] and Georgia and recently signing a partnership with Etihad Aviation Training to recruit eVTOL pilots in Abu Dhabi.
Archer’s milestone with the FAA comes shortly after the regulator reached the SAME STEP with rival eVTOL manufacturer JOBY, publishing the final airworthiness criteria for its JAS4-1 aircraft in March.
“Archer closes in on FAA approval for Midnight eVTOL aircraft” was originally created and published by Airport Technology, a GlobalData owned brand.
[1] battery pack manufacturing site
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