As of February 2009, the International COSPAS/SARSAT System will cease satellite monitoring of 121.5/243 MHz Emergency Locator Transmitter (ELT) beacons.
121.5 and 243 ELTs have been the standard for many years so many of the ELTs are still in operation in many aircraft around the world. Digital 406 MHz ELT beacons have many advantages over analog 121.5/243 MHz beacons. With a 406 MHz beacon, the position of the distress can be relayed to rescue services more quickly, more reliably and with greater accuracy.
Some of the more specific advantages of 406 MHz ELTs include:
- Unique identification, registration data that provides information on the specific owner/operator and aircraft.
- 5 watts pulse type signal power vs. .01 watts continuous
- Global vs. regional coverage
- Search accuracy within 5 km or 100m if GPS position is encoded into message via nav interface (121/243 is only 20 km)

In addition to being much more accurate, dependable, and ideal, 406 MHz ELTs have dramatically decreased in price since their introduction. If you have not already, it would be a good idea to update your ELT as soon as possible to avoid any rush that may occur before 2009. After February 2009, your older 121/243 will not provide adequate search and rescue function should an incident occur with your aircraft.