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We unveil a new non-basal slip mechanism in the {\mu}-phase at room temperature using nanomechanical testing, transmission electron microscopy and atomistic simulation. The (1-105) planar faults with a displacement vector of 0.07[-5502] can be formed by dislocation glide. They do not disrupt the Frank-Kasper packing and therefore enable the accommodation of plastic strain at low temperatures without requiring atomic diffusion. The intersections between the (1-105) planar faults and basal slip result in stress concentration and crack nucleation during loading.