What is a limitation of VOR?

The limitation of VOR, or VHF Omnidirectional Range, being that it requires line of sight is significant because the VOR signal operates at VHF frequencies, which are typically affected by the curvature of the Earth, terrain, and other obstructions. For reliable reception of the VOR signals, the aircraft must be within line of sight of the ground station. This means that if an aircraft is flying at a low altitude, it may lose signal due to terrain, buildings, or other obstacles that can block the signal path. Consequently, the effectiveness of VOR navigation diminishes in areas with high terrain such as mountains or other features that obstruct this direct line to the station.

In contrast, the other choices do not accurately represent the limitations of VOR. Constant internet connectivity is not relevant because VOR systems do not rely on internet access. VOR is not limited to low altitudes; in fact, it can be used effectively across a broad range of altitudes, making it suitable for both low and high-level navigation. Lastly, VOR operates regardless of daylight conditions, as the system does not depend on visual references or sunlight to function.