What is the primary purpose of the marker beacons in an ILS approach?

The primary purpose of marker beacons in an Instrument Landing System (ILS) approach is to transmit approach signals. Marker beacons play a crucial role in providing pilots with positional information as they approach the runway. They emit signals at specific points along the approach path, allowing pilots to determine their proximity to the runway and to verify that they are following the correct glide slope and lateral course.

These beacons correspond to important stages in the approach, such as the outer, middle, and inner markers, each serving to indicate a specific point in the approach sequence. By confirming their location at these points, pilots can maintain situational awareness and ensure they are descending properly in accordance with the approach profile.

Visual orientation, altitude levels, and runway boundaries are essential elements of flight operations, but marker beacons specifically focus on transmitting the necessary signals for the ILS approach, making them vital for safe landings in low-visibility conditions. This dedicated function is what distinguishes marker beacons from other types of navigational aids.