Emergency Transmitters change location frequency

ELTs, also known as beacons, have been locating pilots in distress and directing search and rescue operations since their inception in the 1970s. However, from 1 February 2009 ELTs tuned only to the analogue frequencies of 121.5/243MHz will no longer be picked up by the international satellite system that guides search and rescue teams. Transmissions will only be recognised from digital beacons transmitting on 406MHz. The new frequency will transmit an encoded message that includes a unique identifier and may include location data if the unit is connected to a global positioning system (GNSS). The United Nations bodies that mandate safety requirements for aircraft and maritime vessels globally - the International Civil Aviation Organisation and the International Maritime Organisation - have initiated the changeover because of the superior capabilities of the 406MHz alerting system. Owners of 121.5/243MHz only beacons are advised to replace their systems with 406MHz capable versions with GNSS as soon as possible. The inclusion of GNSS information ensures that very accurate location of an incident is possible, thereby facilitating rescue. New ELTs should still transmit on 121.5/243 MHz as these frequencies will continue to be used in the final homing stages of a rescue. Robb Metcalfe, Head of the General Aviation Inspectorate at the CAA's Safety Regulation Group, said: Owners of ELTs need to check that their transmitters can broadcast on the new frequency, as 406MHz beacons are superior to their analogue predecessors and with GNSS input provide far more accurate information to rescue teams, thereby bringing help to pilots in distress much faster than was possible with the old system. For more information contact Richard Taylor in the CAA Press Office on tel. 020 7453 6025; richardD.taylor@caa.co.uk