Final answer:
To obtain a VOR check signoff, pilots need to perform VOR ground and airborne checkpoints to verify navigation accuracy.
Step-by-step explanation:
To obtain a VOR check signoff according to 91.171, pilots need to perform two activities: VOR ground checkpoint and VOR airborne checkpoint. For a VOR ground checkpoint, pilots must verify that the VOR receiver's indication matches the designated ground checkpoint to confirm navigation accuracy. On the other hand, a VOR airborne checkpoint involves flying over a designated checkpoint while monitoring the VOR indication to ensure its accuracy.