Transmission corridors, pipelines, and high structures run through exactly the terrain that has no signal and no access roads. Today that means sending someone up to walk it, or putting a helicopter in the air. One is slow and dangerous, the other is expensive, and both find problems late. The real obstacle for drones here is not flight. It is what happens past line of sight: no link, no feed, no judgment. The aircraft becomes a camera that follows a route, and the finding happens afterward, when a person scrolls through a few thousand frames.
