What do marker beacons indicate in an ILS system?

Marker beacons in an Instrument Landing System (ILS) serve the specific purpose of indicating particular locations along the approach path to an instrument runway. These beacons provide crucial positional information to pilots as they approach the runway, using distinct signals that denote different phases of the approach.

For example, the Outer Marker indicates the point where the aircraft should be at a specified altitude, while the Middle Marker signifies a point closer to the runway threshold where a decision to land may occur. By providing this accurate location information, marker beacons contribute to safer and more precise landings, especially in low-visibility conditions.

In contrast, weather conditions during approach are monitored using different instruments, and flight path deviations are typically detected through various navigation aids and systems rather than marker beacons themselves. Altitude changes during descent are communicated through air traffic control instructions and onboard instruments rather than through these beacons. Thus, the role of marker beacons as indicators of approach points is essential for successful instrument approaches in aviation.