What is the carrier frequency for the marker beacon system used during an ILS approach?

The carrier frequency for the marker beacon system used during an Instrument Landing System (ILS) approach is 75 MHz. This frequency is specifically designated for marker beacons, which provide pilots with alerts during the approach phase of landing. These beacons transmit identifiable signals that indicate when an aircraft is at certain predefined locations along the final approach path.

Marker beacons are integral to the ILS system, as they help in ensuring that pilots maintain proper approach criteria under various visibility conditions. At 75 MHz, the signal ensures sufficient coverage and can be reliably received by the aircraft's navigation equipment. The use of this frequency is mandated by aviation regulations, making it a standardized part of instrument approach procedures across the aviation industry.