This paper studies the hierarchical Cucker-Smale flocking model of sampled-data second-order discrete-time multi-agent systems under random interactions with time-varying failure probabilities. More precisely, each agent, at each sampling time point, can fail to see any of its superiors in the hierarchy. The random failures are not independent with varying failure rate probabilities. For this model with random interactions, we prove that the flocking would occur almost surely, i.e., agents' velocities will converge almost surely to the velocity of the overall leader of the flock which moves with a varying velocity, the relative positions between agents and the overall leader converge almost surely. Finally, several numerical simulations are provided to illustrate the obtained results. (c) 2018 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.