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Termination of 121.5/243 MHz Satellite Alerting

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National Oceanic and Atmospheric Administration, Commerce.




This notice informs the public that the International Cospas-Sarsat Program plans on terminating 121.5/243 MHz satellite alerting on February 1, 2009. This action responds to guidance provided by the United States National Search and Rescue Committee, the International Maritime Organization, and the International Civil Aviation Start Printed Page 34913Organization. These organizations have requested that 121.5/243 MHz satellite alerting be terminated, due to the high number of false alerts and the negative impact on 121.5/243 MHz emergency beacons users and search and rescue responders. The intended effect of this action is to transition the public from 121.5/243 MHz emergency beacons to emergency beacons operating at 406 MHz.


The termination of 121.5/243 MHz satellite alerting is expected to take place on February 1, 2009.

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Ajay Mehta, SARSAT Program Manager, at (301) 457-5678.

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The National Oceanic and Atmospheric Administration's National Environmental Satellite, Data, and Information Service (NESDIS) manages the Nation's operational geostationary and polar-orbiting environmental satellites, and manages a large collection of atmospheric, geophysical and oceanographic data. Within NESDIS, the Office of Satellite Data Processing and Distribution (OSDPD) manages and directs the operation of the central ground facilities which ingest, process, and distribute environmental satellite data and derived products to domestic and foreign users. OSDPD manages the United States Search and Rescue Satellite-Aided Tracking (SARSAT) Program, and represents the United States to the international Cospas-Sarsat Program. NOAA, along with the United States Coast Guard, United States Air Force and the National Aeronautics and Space Administration, is responsible for implementing the Cospas-Sarsat Program at the national level in the United States.

Cospas-Sarsat's ultimte mission is to assist in saving lives. The Cospas-Sarsat System has assisted in the rescue of more than 11,000 persons since its inception in 1982. The current Cospas-Sarsat Program was established by an inter-governmental agreement signed in 1988 between the Governments of Canada, France, the former Soviet Union and the United States.

The system works in the following manner: Search and rescue instruments are flown on the United States's NOAA polar-orbiting and geostationary-orbiting satellites and Russian Nadezhda series of polar-orbiting satellites. These instruments are capable of detecting signals from emergency beacons referred to as Emergency Locator Transmitters (ELTs), Emergency Position Indicating Radio Beacons (EPIRBs), or Personal Locator Beacons (PLSs). ELTs are primarily used by aircraft, EPIRBs by maritime vessels, and PLSb by individuals on land.

ELTs, EPIRBs, and PLBs may operate on either the 121.5, 243 or 406 MHz frequencies. 121.5/243 MHz beacons transmit an analog signal that does not contain any information about the beacon or user. Alternatively, the 406 MHz beacons transmit a digital code that contains information about the type of beacon. Each 406 MHz beacon in the world has a unique identifier. The unique identifier allows for additional information called registration data to be linked to each beacon. After receipt of ELT, EPIRB or PLB signals by the satellite, the satellite relays the signals to earth stations referred to as Local User Terminals (LUTs).

The LUT, after computing the location of the emergency beacon using Doppler technology, transmits an alert message to its respective Mission Control Center (MCC) via a data communication network. The MCC performs matching and merging of alert messages with other received messages, geographically sorts the data to determine the appropriate search and rescue authority, and subsequently transmits a distress messge to another MCC, an appropriate search and rescue authority such as a national Rescue Coordination Center (RCC) or a foreign SAR Point of Contact (SPOC). In the United States, distress alert data is transmitted to one of the following search and rescue authorities: the United States Air Force Rescue Coordination Center (AFRCC) at Langley AFB in Virginia; the 11th Rescue Coordination Center at Elmondorf AFB in Alaska; one of 10 United States Coast Guard Rescue Coordination Centers; or the Joint Rescue Coordination Center located in Key West, Florida that is responsible for some overseas search and rescue regions.

The USMCC also transmits distress messages internationally to: SAR Points of Contact (SPOCs) in other nations that are considered within the USMCC service area, but outside of its national search and rescue region; or MCCs in other nations.

Termination of 121.5/243 MHz Satellite Alerting

The Cospas-Sarsat Program made the decision to terminate 121.5/243 MHz satellite alerting services in response to guidance from the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO). These two agencies of the United Nations are responsible for regulating the safety of ships and aircraft respectively, on international transits, and handling international standards and plans for maritime and aviation search and rescue. More than 180 nations are members of IMO and ICAO.

Another major factor in the decision to stop satellite processing of 121.5/243 MHz signals is due to problems in this frequency band which inundate search and rescue authorities with false alerts, adversely impacting the effectiveness of lifesaving services. Although the 406 MHz beacons currently cost more, they provide search and rescue agencies with more reliable and complete information to do their job more efficiently and effectively.

The implication of this Cospas-Sarsat decsion is that users of ELTs, EPIRBs, and PLBs that operate on 121.5/243 MHz should eventually begin using beacons operating on 406 MHz if they wish to continue having their beacons detected by satellites. United States registered civil aircraft may carry a 121.5 MHz ELT to satisfy the requirements described in CFR Title 14, part 91, section 207. At the present time, the United States does not mandate the carriage of 406 MHz ELTs. The carriage of 406 MHz ELTs is optional. The United States does not have any mandatory carriage requirements for 121.5 MHz EPIRBs.

Cospas-Sarsat is an international program and the decision to terminate satellite processing of distress signals at 121.5/243 MHz does not mean that users cannot continue to use 121.5/243 MHz emergency beacons. The result of this termination process is that the 121.5/243 MHz signals will no longer be detected by satellites, under the auspices of Cospas-Sarsat. This lack of signal processing could result in a distress signal from a 121.4/243 MHz emergency beacon not being detected, or the detection being significantly delayed. The termination of 121.5/243 MHz processing is planned far enough into the future to allow current 121.5/243 MHz emergency beacon users to transition smoothly to 406 MHz beacons.

(Authority: Pub. L. 98-8, Title I, 104 (1983); 15 U.S.C. 313; 33 U.S.C. 883a; 49 U.S.C. 44720(b))

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Gregory W. Withee,

Assistant Administrator for Satellite and Information Services.

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[FR Doc. 01-16575 Filed 6-29-01; 8:45 am]