Amazing how SoloTrek can misuse the term fail safe!
Boeing (and Moller) defines this to mean that a person/system will be safe even if there is any kind of failure.
SoloTrek, on the other hand, uses fail safe to mean that things will not fail 
 1) Because they have a 3X margin of design
 2) Because of quality control, etc.
 3) Because they "minimize failures" due to good design

Any normal engineering failure/reliability analysis of the design would find scores, if not hundreds of critical failure points 
- that is, if the point fails, for what ever reason, the vehicle crashes.
I am unaware of a single critical failure point for the M400.
There are, on the other hand, many critical failure points for the Boeing VTOL.

- - - -  from their FAQ web page  - - - - - - - 
Why is SoloTrek XFV considered to be "fail-safe"? 

As it relates to SoloTrek XFV, the term "fail-safe" means that within a predefined set of operating limits a
certain component, system, or subsystem will not fail to operate. Most life-critical components on this
aircraft are purely mechanical. They have been designed with safety factors of 3X or greater. 
In other worlds, they are at least three times stronger than they would ever need to be while operating within the
aircraft's design limits.

In the event of a failure of a life-critical electrical component, system, or subsystem, SoloTrek XFV's
fail-safe design relies on an appropriate backup system that continues to provide uninterrupted
operation. Items with such backup systems include the twin electronic fuel pumps, twin electronic
capacitor discharge ignition (CDI) systems, and the electronic fuel injection system. 

Whether mechanical or electrical, all life-critical components, systems, and subsystems on SoloTrek
XFV meet strict quality control inspection standards . . . ensuring a 100% defect-free status. Additionally,
fail-safe design protocols have been applied to every potential failure point. As an example, all
components within the gear boxes are press fit. This ensures that there are no bolts, nuts, bracketry or
other small items to come loose or jam the gears. As another example, various members of the
drivetrain are interconnected using interlocking splines only. Unreliable methods such as key-ways,
cotter pins, and set screws are strictly avoided.
Go to Skycar Home page