The aircraft is equipped with which of the following radio navigation systems?

• A. VOR
• B. ILS
• C. DME
• D. All of the above

Answer: (A)

The main idea is understanding what each radio navigation aid provides. A VOR lets you determine your bearing relative to a ground station by receiving azimuth information, so you can navigate along defined radials from that station. If the aircraft in question is equipped only with a VOR receiver, you can establish direction and fly routes using those radials, but you wouldn’t have distance information or precision approach guidance. ILS offers precise approach guidance using localizer and glideslope, and DME provides distance measurement—neither is available if the aircraft isn’t equipped with their corresponding equipment. Therefore, with the described equipment, VOR is the applicable navigation capability.