What equipment helps pilots navigate using low to medium frequency beacons?

The Automatic Direction Finder (ADF) is the equipment designed specifically for navigating using low to medium frequency beacons. It operates by receiving signals from non-directional beacons (NDBs) that transmit at these frequencies. The ADF allows pilots to determine their position and track their course by indicating the direction to the beacon relative to the aircraft.

By using the ADF, pilots can navigate effectively even in adverse weather conditions or reduced visibility, where other navigation methods might not be as reliable. The ADF is particularly useful in conjunction with other navigational tools, enhancing overall situational awareness during flight.

The other options, while important in aviation navigation, serve different functions. Autopilot systems assist in maintaining the aircraft's flight path but do not provide specific navigation information from beacons. The Flight Management System (FMS) manages the flight plan and optimizes navigation but relies on more advanced systems like GPS and does not directly interpret ADF signals. The Instrument Landing System (ILS) specifically aids in precision landing approaches rather than general navigation over distances using low to medium frequency signals.