Yeah, I agree. "Light aircraft" seems to imply that you are passively-stable and can glide to the ground in case of powerplant failure, which can't be true for these things. Powered-lift seems like a more appropriate classification, but I don't have any insight into what the differences in actual requirements are.

Here's what they are. The "small airplane" certification standards [1] are for airplanes. A helicopter is not an airplane. A powered-lift VTOL incapable of gliding is not an airplane.

"The airplane must be controllable and maneuverable, without requiring exceptional piloting skill, alertness, or strength, within the operating envelope ... (despite) flight control or propulsion system failure"

"Continued safe flight and landing means an airplane is capable of continued controlled flight and landing, possibly using emergency procedures, without requiring exceptional pilot skill or strength. Upon landing, some airplane damage may occur as a result of a failure condition."

So you must be able to glide to a landing, or at least a controlled crash, if you lose engine power.

The FAA is correct here. The "eVTOL" class of aircraft based on quadrotor drone technology will fall out of the sky on either a power or control failure. It's worse than a helicopter, which can usually autorotate.

[1] https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C...

Powered-Lift just means that they aren't using their wing surfaces for lift take-off/landing but are using them for lift during normal flight. They [edit:might] be able to auto-rotate down in the case of a powerplant failure just like a helicopter.

Here is the exact definition:

> (425) Powered-lift. A heavier-than-air aircraft capable of vertical take-off, vertical landing, and low-speed flight that depends principally on engine-driven lift devices or engine thrust for lift during these flight regimes and on non-rotating aerofoil(s) for lift during horizontal flight.

I don't know about these eVTOLs, but the V22 can't autorotate (well technically it can but it probably won't survive the landing).

Ah, you are correct. I edited my comment from "should" to "might". I can't imagine the F-35B is able to auto-rotate either. :)

It doesn't need to. Martin Baker takes care of those situations.

The Joby vehicle looks like it would be capable of controlled descent, it has decent sized wings.

I doubt it. Consider the high wing loading, high drag, and lack of certain control surfaces. Any power loss will result in a quick stall and unrecoverable spin. Most of those powered lift aircraft rely on a mix of redundant systems plus a ballistic recovery parachute for flight safety.

I guess the cutoff is if you can maintain a sink rate low enough to make a landing without killing/severely injuring passengers in an engine-out scenario.

I would expect most of these "scaled up quadcopter" companies to incorporate an emergency parachute system to handle similar to a Cirrus CAPS.