From January 1 2005 all transport aircraft flying
in ICAO airspace must now carry two ELT capable
of trasmitting on 121.5MHZ and 406 MHZ.
After 2009 121.5 frequency is not longer monitored by the SARSAT
if you go over water and you have a liferaft is already with the new elt.
More infos
NOAA SARSAT