Question 31E4

406 MHz satellite EPIRBs (Emergency Position-Indicating Radio Beacons) are designed to transmit distress signals to satellites. * **B is correct** because a 406 MHz EPIRB typically includes: * A **5-watt 406-MHz alert beacon**: This is the primary high-power signal used to transmit the distress message and location to the COSPAS-SARSAT satellite system. * An **Automatic Hydrostatic Release (ARM)**: For Category 1 EPIRBs, this mechanism automatically releases the beacon from its bracket when submerged to a certain depth (e.g., 2-4 meters), allowing it to float free and activate. * A **strobe light**: This provides a visual aid for search and rescue (SAR) teams, especially at night. * **A is incorrect** because the 406-MHz alert beacon normally transmits at 5 watts, not 1 watt, to ensure reliable satellite reception. * **C and D are incorrect** because they refer to a 121.5 MHz beacon as an "alerting" beacon. While many 406 MHz EPIRBs also include a low-power (e.g., 25-100 mW) 121.5 MHz beacon, its purpose is for local *homing* by aircraft, not the primary satellite *alerting*. The primary alerting frequency is 406 MHz. Additionally, 5 watts or 1 watt is an excessively high power for a 121.5 MHz homing beacon.