On Oct. 15, the European Aviation Safety Agency (EASA) released a “special condition” for the emerging generation of vertical takeoff and landing (VTOL) aircraft with distributed thrust units used to generate powered lift and control.
The rulemaking process involves further steps – such as consultation – before the special condition is enforced. But the first version clearly indicates a performance-based approach, in addition to a willingness to avoid the weak points inherent to the design and operation of current helicopters.
The creation of a dedicated regulation for VTOL aircraft, such as electrically powered, multi-rotor flying taxis, was deemed urgent, with a new candidate or company contacting EASA’s headquarters in Cologne, Germany, every week about the topic. The special condition will apply to the Lilium vectored-thrust jet and the multi-rotor Volocopter, two aircraft EASA is already working on.
The existing regulation is not suitable for new VTOL designs, said David Solar, head of EASA’s rotorcraft department. The definition of complexity, for instance, could hardly apply to an electric aircraft with one rotating part. “If we regulate too hard, we will close doors,” he said. In his view, artificial intelligence onboard those aircraft should be allowed without requiring millions of flight-test hours to prove its worth.
Solar admits the usual timescale for rulemaking and certification may be too long for startup companies that are not familiar with aerospace. Their target time to market is very short, he said. But they need to understand what aerospace is about and what a production organization approval is, he pointed out. It slows them down a bit but makes them realize the importance of safety, he added.
While the special condition addresses airworthiness, other aspects such as operations, training and maintenance will have to go through exemption processes. National aviation authorities will be in charge, supported by EASA, said Solar.
The standalone special condition incorporates elements of CS-27 (certification specifications for small rotorcraft) and CS-23 (small fixed-wing aircraft). Its scope is limited to small VTOL aircraft. Up to five passengers and two metric tons, they account for 90 percent of the emerging projects EASA has heard of. “Electric technologies are not ready for larger aircraft yet,” said Solar.
Two categories are created. In the “basic” one, the aircraft must be able to perform a controlled emergency landing after a critical malfunction of the system providing thrust and lift.
The “enhanced” category is for commercial air transport and operations over congested areas. The aircraft can continue to fly after a critical malfunction of the system.
Lessons have been learned from the operation of helicopters. For the enhanced category, in-service monitoring of parts “having an important bearing on safety in operations” is mandatory. Flight data recorders are also obligatory (the data may be transmitted and recorded remotely). A single failure shall not be catastrophic.
Safety is about stuff not falling out of the sky.
Dear Mr. Dubois,
I would like to correct a statement you’re making in the article about EASA VTOL Special Condition. With regards to Artificial Intelligence (AI), I said that the certification approach is a challenge. I said that in current application, AI is based on learning and that beyond simulation, automotive industry and other industries are testing/”educating” AI in real conditions and perform millions of kilometers. In Aviation, this approach may be much more challenging as we cannot log millions of flight hours with a few prototypes. I said that EASA launched an internal reflection on this issue.