Hobbies And Interests
Types
There are two basic types of ELTs. One type transmits on frequencies of 121.5 and 243.0 MHz. The other type transmits on 406.0 MHz. The impact force of a crash will cause the transmitter to activate, providing a signal that can be used to locate the aircraft.
Function
ELTs that transmit on 406.0 MHz are now the standard of the International Civil Aviation Organization (ICAO). Most aircraft in the United States are equipped with 121.5/243.0 MHz ELTs. Either satisfies the regulatory requirements for flight in the United States; U.S. regulations do not require aircraft owners to switch to the newer 406.0 MHz ELTs. U.S. aircraft operating internationally generally are required to have 406.0 MHz ELTs.
Requirements
Most aircraft with more than one seat must have an ELT. Aircraft used in aerial applications and training aircraft operating within 50 miles of their home base are not required to have ELTs.
Considerations
ELT batteries have to be replaced after one hour of operation or after 50 percent of their life. Battery life is determined by the battery's manufacturer. Aircraft records must also reflect the date of next battery replacement.
Warning
Satellites no longer monitor 121.5 MHz or 243.0 MHz. This is the primary way downed aircraft were located in the past. Although these ELTs meet regulatory requirements, their signal is not monitored and search and rescue teams will not be dispatched. Aircraft owners may want to switch to a 406.0 MHz ELT. 406.0 MHz is satellite-monitored and search and rescue teams are dispatched when signals are detected.