Radio Navigation Level 4 Practice Test

The key idea here is the flexibility gained from using electronically scanned microwave beams. An MLS can steer its guidance beams to define the approach path, which means the ground equipment doesn’t have to sit right at the end of the runway or in a fixed alignment. Because the beams can be directed from different angles, you can place the MLS transmitter away from the runway or in a location where terrain, obstacles, or runway geometry would make an ILS installation impractical. That flexibility is what lets MLS be set up at sites where an ILS cannot be installed.

This is why the option about installation location is the best choice. The other options don’t hold up: MLS is not inherently cheaper to install, and power needs depend on the specific system. MLS provides both horizontal and vertical guidance, not vertical guidance only, so that statement isn’t accurate either.