Final answer:
The 406 MHz ELT uses two or three-axis accelerometer units to automatically activate the emergency beacon in the event of a crash, helping with rapid location and rescue efforts.
Step-by-step explanation:
The 406 MHz ELT provides options of two or three axis accelerometer units for automatic activation of the emergency beacon; should the aircrew not be able to activate the beacon prior to the emergency. These accelerometer units are designed to detect sudden changes in forces along different planes, indicating a potential crash or other forms of impact that would necessitate an emergency response. This technology greatly enhances the chances of rapid location and rescue in the event of an aircraft accident.