[iofj]

There are so many planes that cannot land in the event of complete electrical failure ... starting with every last modern passenger airliner. There the problem is that human strength is not enough to control flaps and hydraulics are too heavy (translation: possible but too expensive), but if the electrical infrastructure completely fails ... it's over. Plane will lose control, rapidly spin out of control and dive chaotically into the scenery.

It hasn't happened yet.