[FabHK]

The Volocopter has 18 rotors (fixed, electric motor, with 1 degree of freedom - doesn’t get much simpler) attached to 9 battery packs, and at least 4 can fail (even more when they are “nicely” distributed) and it's still controllable and landable. And they could still throw in a ballistic rescue parachute.

[gambiting]

Unless of course the power supply fails, in which case we're back to the point I brought up earlier - you have neither autorotation nor gliding to fall back on, the vehicle just falls out of the sky like a brick - the parachute would help but I'm not sure how feasible that is.

[fiter]

Which power supply? According to the poster there are 9 separate battery packs which, presumably, are the power supplies.