Power drive unit electromagnetic latch

A no-back device for a power drive unit is configured such that, during operation of the power drive unit, the no-back device does not supply magnetic or frictional force against power drive unit rotation. The no-back device is implemented either redundantly or no-redundantly, and includes a latch rotor and an electromagnet. In both embodiments, the latch rotor is coupled to the power drive unit to rotate therewith, and the electromagnet is coupled to receive a flow of current and, upon receipt thereof, generates a magnetic field force that opposes rotation of the latch rotor. In the redundant embodiment, the no-back device further includes one or more permanent magnets, and the magnetic field generated by the electromagnet selectively opposes or aids the magnetic field supplied by the permanent magnet(s).