FREQUENTLY ASKED QUESTIONS

The governments of Canada, France, Russia and the United States have signed an agreement to provide for the long-term operation of the system and to support the objectives of the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO) concerning search and rescue. In addition, more than 29 other countries have associated themselves with the Program by providing ground equipment or formally declaring themselves as users of the System.

Cospas is a Russian acronym for “Space System for Search of Vessels in Distress”

The web site www.cospas-sarsat.org contains more information on the program.

What is the Cospas-Sarsat Secretariat?

The Cospas-Sarsat Secretariat is the permanent administrative organ of the international program responsible for assisting the Cospas-Sarsat Council in implementing the Program. The Secretariat contains a small, specialized and dedicated staff that assists in organizing meetings, administering the international budget, and providing technical and operational assistance.

When was the Cospas-Sarsat formed?

The first Cospas satellite launch was in 1982, during the same year the first rescue using the system was recorded. The system was declared operational in 1985. At this time the four member agencies of Cospas-Sarsat were working under a Memorandum of Agreement. As the program matured, it was decided to have an intergovernmental agreement between the Governments of Canada, France, United States, and at that time the Union of Soviet Socialist Republic. This intergovernmental agreement was signed in 1988 and established the Cospas-Sarsat Council and the Secretariat.

Why is the National Oceanic and Atmospheric Administration (NOAA) involved in Search and Rescue?

Text Box:

NOAA operates the nation’s civil environmental satellites. These satellites are used to monitor the weather. These satellites also carry instruments that detect emergency beacons. As NOAA operates the satellites that carry search and rescue instruments and operates the equipment to receive and process distress signals, it is the lead agency in the United States for the Cospas-Sarsat Program. NOAA also represents the United States to the international Cospas-Sarsat Program.

Who are the other agencies involved with Cospas-Sarsat in the United States?

Besides NOAA, the U.S. Air Force Rescue Coordination Center (AFRCC) at Langley Air Force Base (http://www2.acc.af.mil/afrcc/) is responsible for inland search and rescue coordination, the U.S. Coast Guard responsible for maritime search and rescue (http://www.uscg.mil/hq/g-o/g-opr/sar.htm), and the National Aeronautics and Space Administration (http://searchandrescue.gsfc.nasa.gov) responsible for research and development are partners in the national Cospas-Sarsat program.

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... about Beacons

What is an EPIRB?

An EPIRB is an emergency position-indicating radio beacon. It is a device that can be automatically or manually activated to transmit a distress signal to a satellite. EPIRBs that activate automatically typically have a hydro-static release mechanism that allows the beacon to release from its bracket, float to the surface and start transmitting. The beacon, along with the bracket, has to sink to approximately 3 meters before it can activate. This should be taken into account when mounting an automatic type EPIRB.

EPIRBs transmit at either 121.5 MHz or 406 MHz. More information on both frequencies is available under the “Phase Out of 121.5 MHz Satellite Alerting” section below. 121.5 MHz EPIRBs can either be Class A or Class B. Class A EPIRBs can be activated either manually or automatically, Class B EPIRBs can only be activated manually. 406 MHz EPIRBs can either be Category I or Category II EPIRBs. Category I EPIRBs can be activated either manually or automatically, Category II EPIRBs can only be activated manually.

Use of Class A and B EPIRBs will be discontinued in the near future. Please refer to the U.S. Coast Guard’s Office of Search and Rescue homepage (http://www.uscg.mil/hq/g-o/g-opr/sar.htm) for more information.

What are the differences in EPIRB Categories?

A Category I EPIRB is one that is designed to be automatically activated when the beacon sinks to a certain depth (anywhere from 12 – 15 feet below the surface) or it can be manually activated. A Category II EPIRB is one that can only be activated manually.

What is an ELT?

An ELT is an emergency locator transmitter. It is a device that can be automatically or manually activated to transmit a distress signal to a satellite. ELTs that activate automatically typically have a “G” or gravity switch that triggers the ELT when it senses that a crash has occurred. There are several types of ELTs:

$ Automatic Fixed ELTs are intended to be permanently attached to the aircraft before and after a crash and are designed to aid search and rescue teams in locating a crash site.

$ Automatic Portable ELTs are intended to be rigidly attached to the aircraft before the crash but readily removable from the aircraft after a crash

$ Survival ELTs do not activate automatically and are intended to be removed from the aircraft

$ Automatic Deployable ELTs are intended to be rigidly attached to the aircraft before the crash and automatically deployed after crash force sensor has determined that a crash has occurred.

ELTs can transmit at either 121.5 MHz or 406 MHz, however satellite alerting of 121.5 MHz distress signals will be discontinued starting in February, 2009. More information on both frequencies, and on the phase-out of satellite alerting for 121.5 MHz ELTs is available under the “Phase-Out of 121.5 MHz Satellite Alerting” section below.

Text Box: What is a PLB?

A PLB is a personal locator beacon designed to be carried by an individual. They can only be activated manually. PLBs can be used by hikers, canoers, and other people operating in remote areas.

What are the differences in beacon classes?

The only difference is the operating temperatures. A Class 1 406 MHz emergency beacon is designed to operate between -40°C to +55°C and a Class 2 406 MHz emergency beacon is designed to operate between -20°C to +55°C.

How can I get in touch with my 406 MHz beacon manufacturer?

A complete list of Cospas-Sarsat approved manufacturers is provided at

http://www.cospas-sarsat.org/Beacons/beaconManufactureList.htm

Are 406 MHz PLBs legal for use in the United States?

406 MHz PLBs have been authorized for use by the Federal Communications Commission (FCC) starting July 1, 2003.

What is the difference between emergency beacons that operate at 121.5 MHz and those that operate at 406 MHz?

121.5 MHz beacons transmit an analog signal that can only be detected by low-earth, or polar orbiting satellites. The analog signal does not contain any information about the beacon or its user. Alternatively, 406 MHz beacons transmit a digital signal that contains information on the type of beacon and owner. Additionally, 406 MHz beacons can be linked to registration information that can provide search and rescue forces valuable information when responding to a distress signal. More information on the difference between 121.5 and 406 MHz beacons is available under the “Phase-Out of 121.5 MHz Satellite Alerting” section below.

Click here to see a 121.5 MHz vs. 406 MHz Comparison Chart

What is the beacon identification code and where can I find it on the beacon?

The beacon ID, also referred to as the Unique Identification Number (UIN) is comprised of 15 hexadecimal characters. Hexadecimal characters are made of numbers (0 through 9) and the letters A, B, C, D, E and F. Please note that the letter “O” as in “Oscar” and the letter “I” as in “India” are not allowed.

What is the Unique Identifier Number (UIN)?

The UIN is the same as the beacon ID, see above.

How do I test my emergency beacon?

That depends on the type of beacon you own. You can test your 121.5 MHz ELTs only during the first five (5) minutes after any hour and you may only activate the ELT for three audible sweeps. If operational tests must be made outside of this period, they should be coordinated with the nearest FAA Control Tower or FSS. If the antenna is removable, a dummy load should be substituted during test procedures. In any case airborne tests are not allowed.

406 MHz emergency beacons should never be activated unless you are in grave and eminent danger. 406 MHz emergency beacons should only be tested using the “self-test” feature of the beacon or the beacon should be taken to an authorized dealer or test facility. A list of U.S. Coast Guard units that can test your 406 MHz beacon can be found at www.uscg.mil/hq/g-m/cfvs. Look under EPIRB information.

The International Maritime Organization has published guidelines for annual testing of 406 MHz EPIRBs that might be of use of beacon owners in general. Some of the relevant guidelines state that an examination of an installed 406 MHz beacon should include:

$ checking the position and mounting of automatically activated EPIRBs and ELTs;

$ carrying out a visual inspection for defects;

$ carrying out the self-test routine;

$ ensuring that the beacon ID is clearly marked on the outside of the beacon;

$ checking the battery expiry date; and

$ checking the hydrostatic release and its expiry date for automatically activated EPIRBs.

Do I need to inspect my ELTs, and how often?

Yes, you must inspect your ELT once a year. Each ELT must be inspected for proper installation, battery corrosion, operation of the controls and crash sensor, and the presence of a sufficient signal radiated from its antenna.

Why can’t I register a 121.5 MHz emergency beacon?

406 MHz emergency beacons have a unique identifier that allows us to link the emergency beacon to registration information. A 121.5 MHz emergency beacon transmits an analog signal that does not contain any information. Therefore, there is no way to register the beacon.

Who is required to carry an ELT?

In general, all U.S. registered civil airplanes must have an automatic type ELT attached to the aircraft. The ELT may be a 121.5 MHz or 406 MHz ELT. More details on the carriage requirements may be found at www.access.gpo.gov under Title 14 CFR Part 91.

Who is required to carry a 406 MHz EPIRB?

In general, U.S. commercial fishing vessels, uninspected passenger vessels which carry six or more people, and uninspected commercial vessels are required to carry an EPIRB. You should look at the specific requirements to determine whether you need to carry an EPIRB. The requirements are available in the Code of Federal Regulations which can be found at www.access.gpo.gov under Title 46 - Shipping. Regardless of the requirements, if you operate a vessel outside of radio range it would be a good idea to carry an EPIRB.

Is there any guidance on how to use 406 MHz EPIRBs?

You should always follow the manufacturer’s instructions when using or testing your EPIRB. In general an EPIRB should be placed in the water and tethered to the survival craft. EPIRBs which are not meant to float in water should be placed in the survival craft in a vertical position with the antenna clear of all obstacles, including your self and others in the survival craft. If your EPIRB has a GPS interface you should ensure that the EPIRB is outside enclosures, such as a carbon-fiber vessel hull, which could prevent acquisition of navigational satellite signals by the GPS.

What is a false alert?

A false alert is an activation of an emergency beacon in a non-distress situation. Examples of false alerts include accidentally turning on an emergency beacon, improperly testing a beacon or incorrectly mounting an emergency beacon so that it falls out of its bracket and activates.

What can I do to reduce false alerts?

You have the primary responsibility to prevent false alerts. You should ensure that you only activate an emergency beacon in situations of grave and imminent danger. You should also follow the manufacturer’s instructions for testing your beacon. Lastly you should ensure that automatically activated beacons are properly mounted so that a simple “bump” will not cause them to fall out of their bracket and activate.

ELTs

Caution should be exercised to prevent the inadvertent activation of ELT's in the air or while they are being handled on the ground. Accidental or unauthorized activation will generate an emergency signal that cannot be distinguished from the real thing, leading to expensive and frustrating searches. A false ELT signal could also interfere with genuine emergency transmissions and hinder or prevent the timely location of crash sites. Frequent false alarms could also result in complacency and decrease the vigorous reaction that must be attached to all ELT signals.

Numerous cases of inadvertent activation have occurred as a result of aerobatics, hard landings, movement by ground crews and aircraft maintenance. These false alarms can be minimized by monitoring 121.5 MHz and/or 243.0 MHz as follows:

(a) In flight when a receiver is available.

(b) Before engine shut down at the end of each flight.

(d) When maintenance is being performed near the ELT.

(e) When a ground crew moves the aircraft.

(f) If an ELT signal is heard (sounds like a siren), turn off the aircraft's ELT to determine if it is transmitting. Newer ELTs have a cockpit mounted switch; however you will need access to the unit itself if it’s an older model. If it has been activated, maintenance might be required before the unit is returned to the "ARMED" position. You should contact the nearest Air Traffic facility or Flight Service Station (FSS) 1-800-WXBRIEF and notify them of the inadvertent activation.

Maintain your ELT regularly. Low batteries can cause erroneous signals and generate false alarms. Conversely, false alarms can cause low batteries. So, make sure you've got strong batteries in your ELT.

EPIRBs

Always test your EPIRB in strict accordance with the manufacturer’s recommendations. Most EPIRB activation switches have a test position. This test position allows the entire unit (electronics, battery, and antenna) to be tested without generating a false alarm. Ensure that your beacon is registered with NOAA. This does nothing to reduce false alarm rates, but does have a dramatic effect on the impact of a false alarm. If the EPIRB is properly registered, the situation will be resolved with a phone call. It will also help speed rescue in an actual distress.

Affix your proof-of-registration decal on the EPIRB so it can be easily read without taking the EPIRB out of its bracket. A surprising amount of false alarms are generated by people (sometimes Coast Guard safety inspectors) doing so to check the decal. Never remove the EPIRB from its bracket without first switching it to the "OFF" position (unless of course, you're actually in distress). Also, never allow it to be removed by others. A lot of false alarms are generated by curious passengers. Another common source of false alarms is from crew members removing the EPIRB to paint behind it.

Maintain your EPIRB. Ensure that the batteries are within their expiration date and that all manufacturer recommendations are followed. Any time that the EPIRB is not on the vessel, it should be switched “OFF.”

Finally, realize that the Cospas-Sarsat satellites are very good at what they do...detecting emergency beacons. Activation of any 406 MHz beacon, even for just a few seconds, will usually be detected.

What should I do if I have accidentally activated my emergency beacon?

If for any reason your beacon is activated accidentally you should contact the appropriate rescue coordination center, Air Traffic facility or Flight Service Station (FSS) 1-800-WXBRIEF . In the Atlantic Ocean or the Gulf of Mexico you should contact the U.S. Coast Guard Atlantic Command Center at (212) 668-7055. In the Pacific Ocean region you should contact the U.S. Coast Guard Pacific Area Command Center at (510) 437-3700. On land, you should contact the U.S. Air Force Rescue Coordination Center at (757) 764-8112. If you cannot contact these organizations directly, you should use any means available to inform the appropriate authorities that a false alert has been transmitted and should be cancelled.

How can I dispose of my emergency beacon?

You should ensure that when your beacon needs to be disposed of (for example when its damaged or when a ship is sold for scrap) it should be made inoperable, either by removing its battery and, if possible, returning it to the manufacturer, or by demolishing it. If a beacon is to be returned to the manufacturer with the battery still installed, it should be wrapped in tin foil to prevent transmission of signals during shipment. Please inform the NOAA/USMCC if you sell or dispose of a registered 406 MHz beacon.

If I’m a pilot should I monitor for 121.5 MHz signals?

Yes. Pilots are encouraged to monitor 121.5 MHz and/or 243.0 MHz while in flight to assist in identifying possible emergency ELT transmissions. On receiving a signal, report the following information to the nearest air traffic facility:

(a) Your position at the time the signal was first heard.

(b) Your position at the time the signal was last heard.

(d) Your flight altitudes and frequency on which the emergency signal was heard: 121.5 MHz or 243.0 MHz. If possible, positions should be given relative to a navigation aid. If the aircraft has homing equipment, provide the bearing to the emergency signal with each reported position.

How do I maintain my beacon?

All beacons need to be tested and serviced for water tightness, the battery, external damage and signal strength. Beacons should be serviced whenever the battery needs replacing. Usually the manufacturer or distributor services the beacon.

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… about Beacon Registration

Who has to register a 406 MHz emergency beacon?

All 406 MHz emergency beacon owners/operators are required to register their 406 MHz emergency beacon (ELTs and EPIRBs) with NOAA’s SARSAT program. This is a requirement from the Federal Communications Commission (FCC). The following web site contains more information on the regulation www.access.gpo.gov., look under Title 47 - Telecommunication.

How can I register my 406 MHz EPIRB, ELT or PLB or update my information?

There are several ways to register you 406 MHz beacon with NOAA. You may send the registration card or information to the address below or fax it to (301) 568-8649:

Beacon Registration

NOA/NESDIS, E/SP3, Rm 3320, FB4

5200 Auth Road

Suitland, MD 20746

Alternatively, you can save time and money, and improve the accuracy of the information you provide by registering your beacon via the Internet at www.beaconregistration.noaa.gov

How do I update my beacon registration information?

You can now go to www.beaconregistration.noaa.gov and make the update. If you have not previously accessed your beacon registration using the internet, you need to choose the 2^nd option (Access Beacon Previously Registered By Mail).

Does NOAA automatically send of Proof-of-Registration decals and Text Box: confirmation reports?

Yes. You should receive a Proof-of-Registration decal when you initially register your beacon and when you confirm your registration information every two years. In either case, the decal is sent to the postal address listed on the registration.

Are there times when I will receive a Proof-of-Registration decal even though it hasn’t been two years since I registered, or last updated my information?

Yes, this can happen when you change or update your information. Depending on the type of beacon you have, a new proof-of-registration decal will be sent in the following cases:

EPIRB: When you update the vessel name

When you select the renew registration option

ELT: When the tail number on the aircraft has changed

When you select the renew registration option

PLB: When the owner name changes

When you select the renew registration option

Or, you’ll receive a new decal when you select the “Replace Decal” option on the web-based registration system.

How long is my registration information valid in the NOAA registry?

The registration information, and the corresponding proof-of-registration decal, is valid for two years. The FCC requires that you renew your registration every two years. However, you are encouraged to provide updates to your registration anytime it’s required.

Do I need a ship station license or a documentation number to register an EPIRB?

You do not need a ship station license or a documentation number to register an EPIRB.

Text Box: How can I contact the Federal Communications Commission (FCC)?

They can be reached at (888) 225-5322 or at www.fcc.gov.

To whom is my 406 MHz emergency beacon registration information released?

The registration information is only released to search and rescue authorities such as the U.S. Coast Guard and the U.S. Air Force. In certain cases NOAA may release your registration information to beacon manufacturers or service agents so that they may send you urgent service announcements.

NOAA, under the Privacy Act of 1974 (as amended), is required to adopt minimum standards for the collection and processing of personal information and to publish detailed descriptions of these procedures. The Privacy Act also limits the making of such records available to other public and private agencies or parties. Lastly, it requires agencies to make records on individuals available to them upon request, subject to certain conditions and exclusions.

The Privacy Act has four basic policy objectives:

$ to restrict disclosures of personally identifiable records;

$ to grant individuals more rights to access records agencies maintain on them;

$ to grant individuals the right to seek amendments to agency records maintained on themselves; and

$ to establish a code of "fair information practices" which requires agencies to comply with statutory norms for collection, maintenance, and dissemination of records.

What happens if I do not register my 406 MHz emergency beacon?

The System will still work but rescue could be delayed. The Cospas-Sarsat System is designed to provide both identification and location information. Identification information can be provided two ways: (1) information such as the radio call sign or aircraft tail number can be encoded into the 406 MHz emergency beacon and/or (2) the 406 MHz emergency beacon can be registered in a national registration database such as the one NOAA maintains.

As long as the System is able to obtain a position (either using Doppler processing or through the use of new beacons that can transmit their position as part of the 406 MHz message) search and rescue personnel can respond to a distress signal. However, when a position is not available the search and rescue personnel have to rely on registration information. It’s in these cases that rescue could be delayed until the System can obtain a position. Even with a position, the response may be delayed until the search and rescue personnel try to determine the nature of the distress, and their capability to respond to the location of the distress. The response would also vary country by country. NOAA recommends that you try to list two contacts, one of which, the search and rescue personnel would be able to reach at any time of the day.

What can I do if I have a 406 MHz emergency beacon coded for a country that does not maintain a 406 MHz emergency beacon registration database?

You will have to register your beacon in the International Beacon Registration Database which will be maintained by Cospas-Sarsat. Cospas-Sarsat is in the process of establishing an international 406 MHz emergency beacon registration database that would be available to all beacon owners that have no place to register their beacon. This database is expected to be available via the Internet in December 2005.

Who should I list as an emergency point of contact on my 406 MHz emergency beacon registration form?

You should list family and/or friends that can be easily contacted (e.g., carry a cell phone, or are usually available at work or at home) and would have knowledge about where you sail or fly.

Why do I have to re-new my registration every two years?

The registration information you provide is used to help you in case of an emergency. Therefore, the information has to be current and accurate. The International Maritime Organization (IMO) recommends that registration information be updated periodically. Nationally, the Federal Communications Commission (FCC) requires that 406 MHz EPIRB owners “advise NOAA in writing upon change of vessel or EPIRB ownership, transfer of EPIRB to another vessel, or any other change in registration information.” Furthermore, the FCC requires that “aircraft owners shall advise NOAA in writing upon change of aircraft or ELT ownership, or any other change in registration information. Fleet operators must notify NOAA upon transfer of ELT to another aircraft outside of the owners control, or an other change in registration information.” More importantly, accurate registration information could help save your life.

What do I do if I lend my emergency beacon to someone?

That depends on how frequently you lend your beacon and for how long you lend your beacon. If you frequently lend your beacon to someone else or its used on another vessel you may wish to note this fact under the “ADDITIONAL DATA” section of the registration form. The same holds true if you lend you beacon to someone for an extended period. If this occurs infrequently or only for a short time you should update your registration via the web-based registration database (www.beaconregistration.noaa.gov). In these cases, adding an email address is important so that you are immediately notified when the registration is updated.

How do I change registration information if I purchased a beacon from someone else?

First of all the person you bought the beacon from must have told us that the beacon was sold, in which case you simply log on to our web-based registration database (www.beaconregistration.noaa.gov) and register the beacon as a “NEW REGISTRATION” and complete the online form.

If the previous owner has not informed us that the beacon was sold, you’ll need to call us to assist you. You’ll be asked to provide some details about the vessel or aircraft that the beacon belongs to.

How do I find my beacon model number?

The model number is usually provided on the beacon itself, along with the serial number and the FCC ID. If you are having trouble determining the model number the Cospas-Sarsat Program maintains a list of manufacturers and model numbers for all beacons that have been approved by Cospas-Sarsat. The link to this information is at

http://www.cospas-sarsat.org/Beacons/typeApprovedList.htm

What does INMARSAT mean?

INMARSAT owns and operates a global satellite network and offers mobile satellite communications for maritime, aviation and land-based users. This is supplemental information for registration purposes only. If you do not have a satellite or INMARSAT phone you can leave this field blank.

What’s a Radio Call Sign?

In broadcasting and radio communication, a callsign or call sign is a unique designation for a transmitting station. They can be formally assigned by a government agency, informally adopted by individuals or organizations. In the United States they are assigned by the FCC. This is supplemental information for registration purposes only. If you do not have a radio call sign can leave this field blank

Can I have a proof-of-registration decal sent to another address?

Unfortunately, we can only send the decal to the owner’s address listed on the registration form.

How do I set up my password?

Access the web-based registration database (www.beaconregistration.noaa.govv/rgdb) and select the “ACCESS BEACON PREVIOUSLY REGISTERED BY MAIL” option and answer the questions on the screen. Please note that you must have access to the previous registration information.

How do I get a password if I’ve forgotten it?

You can access the web-based registration database (www.beaconregistration.noaa.govv/rgdb) and select the “ACCESS BEACON PREVIOUSLY REGISTERED BY MAIL” option and answer the questions on the screen. Please note that you must have access to the previous registration information, or you can call us.

Unfortunately, due to security reasons, we can no longer email your password to you.

How long does it take to receive my proof-of-registration decal in the mail?

The usual mailing time for the proof-of-registration decal is approximately 7-10 days. If after two weeks you have not received you decal please contact us so that we can send a replacement.

Why does the web-based registration system take me to the “LOG IN” page when I hit “SUBMIT”?

Chances are you took longer than 20 minutes to complete or update your registration. If you need more than 20 minutes to complete your registration form you can hit “SUBMIT” during the process and then [do what]. If you continue to encounter problems please fax the registration information to us at 301 568-8649.

I mail a registration form to a Washington, D.C. address but it’s returned to me, why is that?

While our physical location has not changed, our mailing address has. There are some older registration forms in circulation that contain a Washington, D.C. address which is no longer valid. To speed up the process you can register you beacon on-line at www.beaconregistration.noaa.gov, fax the form to (301) 568-8649, or mail the form to:

Beacon Registration

NOAA/NESDIS, E/SP3, Rm 3320, FB4

5200 Auth Road

Suitland, MD 20746

When do I receive a renewal request (or confirmation request) for my beacon registration?

The renewal letter or request for confirmation is mailed approximately 60 days prior to the proof-of-registration decal expiring.

Do I receive a renewal letter or request for confirmation after I’ve flagged my registration as “OUT OF SERVICE”?

No, you will not receive a renewal letter or request for confirmation if your beacon is out of service.

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... about Satellites

What is the difference between a geostationary orbit and a polar/low earth orbit?

A satellite in a geostationary orbit is at an altitude of 22,300 miles (35,890 kilometers). The satellite moves in a circular orbit in the equatorial plane around the Earth at the same speed that the Earth rotates. Because of this, it appears to remain suspended all the time over a fixed point on the Earth's surface. This orbit is perfect for communications satellites because they are always in view of the ground station providing continuous TV and telecommunications services to customers. This position is also ideal for making uninterrupted observations of the weather or environmental conditions in a given area. This same principle allows it to monitor for 406 MHz distress beacons. However, satellites in geostationary orbit cannot see the polar regions of the world.

A polar or low earth orbit allows the satellite to observe the entire Earth's surface as it rotates beneath it. Most of these orbits are at an altitude of 500 miles (800 km) and take about 100 minutes to revolve around the earth. The sun-synchronous orbit is a special case of a polar orbit with inclination of 98.7 degrees, that precesses at exactly the required rate (~ 1 degree per day) to remain in the same local time plane as the Earth rotates around the sun. Satellites in polar orbit provide emergency beacon users with global coverage (including the polar regions).

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Text Box:

... about Search and Rescue

What is search and rescue?

In general search and rescue, or SAR, is a lifesaving service provided through the combined efforts of the federal agencies signatory to the National SAR Plan, and the agencies responsible for SAR within each state. Operational resources are provided by the U.S. Coast Guard, DOD components, the Civil Air Patrol, the Coast Guard Auxiliary, state, county and local law enforcement and other public safety agencies, and private volunteer organizations. Services include search for missing aircraft and vessels, survival aid, rescue, and emergency medical help for the occupants after an accident site is located.

What is the National SAR Plan?

By federal interagency agreement, the National Search and Rescue Plan provides for the effective use of all available facilities in all types of SAR missions. These facilities include aircraft, vessels, pararescue and ground rescue teams, and emergency radio fixing. Under the plan, the U.S. Coast Guard is responsible for the coordination of SAR in the Maritime Region, and the USAF is responsible in the Inland Region. To carry out these responsibilities, the Coast Guard and the Air Force have established Rescue Coordination Centers (RCC's) to direct SAR activities within their regions. NOAA provides satellite alerting in support of the National SAR Plan.

How can I contact Rescue Coordination Centers (RCC) in the United States?

Text Box: You can contact the following Coast Guard RCCs at:

You can contact the following Air Force RCCs at:

Text Box:

Air Force RCC - 804-764-8112

Alaskan Air Command Rescue Coordination Center - 907-552-5375

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... about the Phase out of 121.5 MHz Satellite Alerting

How is the National Oceanic and Atmospheric Administration (NOAA) involved in the issue of phasing-out 121.5 MHz satellite alerting?

The Cospas-Sarsat satellites carry instruments that relay distress signals from 121.5 MHz emergency beacons, and from 406 MHz emergency beacons. The United States and Russia provide the satellites (France and Canada provide SAR instruments carried on the United States satellites).

NOAA is the lead agency in the United States for the Cospas-Sarsat Program. NOAA represents the United States to the international Cospas-Sarsat Program, as well as manages and operates the satellites that carry instruments to relay distress signals.

Who in the United States is involved in making the decision?

NOAA’s primary mission is to describe and predict changes in the Earth's environment, and conserve and manage the nation's coastal and marine resources. It is not a SAR organization. Therefore, NOAA has to rely on partnerships to carry out its role as the lead agency in the United States for the Cospas-Sarsat Program. The primary partners implementing the Cospas-Sarsat Program at a national level are:

• NOAA (program operation and management);

• the United States Coast Guard (responsible for maritime search and rescue);

• the United States Air Force (responsible for inland search and rescue); and

• the National Aeronautics and Space Administration (NASA) (responsible for research and development).

These agencies have signed a Memorandum of Agreement to implement the Cospas-Sarsat Program at a national level and to support the objectives of the National Search and Rescue Committee^{^[1]} (NSARC). NSARC is a standing federal committee formed to:

oversee the National Search and Rescue Plan and coordinate development of interagency policies and positions on SAR Matters;

· provide an interface with other national agencies involved with emergency services; and

· provide a forum for coordinated development of compatible procedures and equipment to increase the effectiveness and standardization of SAR operations.

The NSARC, as the coordinating SAR organization in the United States, has formally adopted the position that 121.5 MHz satellite alerting should be phased-out.

Who is involved in the decision making process at an international level?

Besides the Cospas-Sarsat Program, the IMO and ICAO are involved in the decision to phase-out 121.5 MHz satellite processing. Cospas-Sarsat has stated that it will continue to provide 121.5 MHz and 406 MHz alerting services as long as they contribute to efficient SAR operations. In this respect they will take into account the views of IMO and ICAO.

IMO was established as a specialized agency of the United Nations in 1948 to deal with maritime affairs and to promote marine safety and prevent marine pollution. The Maritime Safety Committee (MSC) of IMO deals with various aspects of the design, equipment and operation of ships. The sub-committee on communications and search and rescue (COMSAR) deals with all aspects of distress and non-distress communications and search and rescue. COMSAR-3 in February 1998 recommended that 121.5 MHz satellite alerting should be phased-out, and a plan should be developed by Cospas-Sarsat. The MSC-70 in December 1998 endorsed the sub-committee’s recommendation and informed Cospas-Sarsat of their decision.

ICAO was established as a specialized agency of the United Nations in 1947 to deal with aviation issues and to develop international civil aviation in a safe and orderly manner. The Air Navigation Commission of ICAO deals with technical matters including telecommunications and search and rescue. The Air Navigation Commission at its 10^th Meeting of the 149^th Session in December 1998 proposed amendments to Annexes 6 and 10 mandating carriage of 406 MHz ELTs for aircraft that fall under the ICAO convention. This requires all new aircraft to carry 406 MHz ELTs by 2002 and all aircraft to carry 406 MHz ELTs by 2005. The Air Navigation Commission also stated that satellite processing of 121.5 MHz could be phased-out by 2008. The ICAO council in March 1999 adopted the amendments.

In summary, the two international organizations that deal with maritime and aviation search and rescue have stated that 121.5 MHz satellite alerting has a negative impact on SAR operations and is no longer required.

Who is affected by the decision and how?

There are many organizations/agencies affected by the decision. Agencies involved with search and rescue (the United States Air Force and United States Coast Guard) will experience less false alerts and more timely, accurate and reliable alert information.

Aviators and mariners are also affected by the decision. They will need to switch to 406 MHz beacons if they desire to be detected by satellites. The carriage of 406 MHz beacons is already mandated for many commercial vessels. Therefore, the decision has minimal impact on this group. Recreational boaters, who are not currently mandated to carry 406 MHz beacons, will need to transition to 406 MHz beacons in the future. Indications are that the transition has already begun. The number of recreational boaters who have purchased 406 MHz beacons has increased dramatically in the past few years. This coupled with the drop in price of 406 MHz EPIRBs (down to $500.00 for a Category II EPIRB) will ensure that most recreational boaters will be able to make the transition.

This trend is not evident in the aviation community. ELTs have not been introduced on a large scale due to the cost of the ELT unit and the associated installation costs. There is no reason to believe that the cost of 406 MHz ELTs will not be reduced as the market expands. Nevertheless, it is the cost and the failure rate of older TSO-C91 ELTs that have caused aviation organizations to resist a transition to 406 MHz ELTs, or to require mandatory carriage. Therefore, the aviation community may be most affected by the decision to phase-out 121.5 MHz processing. One of the reasons the phase-out is proposed for 2009 is to allow the aviation community (including ELT manufactures and national administrations) to prepare and plan for the termination.

As the aviation community is affected by this decision what is the FAA’s position on the issue?

To support international aviation safety, the FAA agreed with ICAO’s proposal to mandate carriage of 406 MHz ELTs in international operations. However, the FAA disagreed with the original termination [of 121.5 MHz satellite processing] date of 2005 as it would not allow an orderly transition for the 100,000 general aviation aircraft in the United States. The FAA proposed an alternative date of 2008. 2009 was finally accepted internationally.

Why was the decision made to phase-out 121.5 MHz satellite alerting?

The search and rescue community recommended phasing out 121.5 MHz satellite alerting because:

• Responding to the tremendous number of 121.5 MHz false alerts (most of which originate from non-beacon sources) relayed by satellites is not efficient, and needlessly expends limited resources, or diverts resources from real incidents (there were an average of 120,000 false alerts per year over the past three years in the United States alone)

• Identification information is not available which means a launch of resources is usually necessary to resolve the incident.

• The 406 MHz system, which was designed for relay through satellites, is operational and provides increased reliability, identification information, better location accuracy, a global capability, and quicker alerting through the geostationary satellite system.

The following table shows the difference between the 121.5 and 406 MHz systems^{^[2]}:

Features

121.5 MHz Beacon

406 MHz Beacon

Timeliness

Ambiguity Resolution

Waiting Time

Store and Forward

Takes two passes (> than 90 min)

45 – 90 minutes

None - increases waiting time

Correctly identified in 95% of the cases (<45 minutes)

<5 minutes with GEOSAR

Beacons are detected even if LUTs are not tracking the satellite

Location Accuracy

Doppler

GPS

12-20 nm accuracy

None

2-5 kilometer accuracy

100 meters

Identification

Nationality and Type

User Identification

Registration

None

Nationality and type available

User Identification (e.g. Tail Numbers) can be encoded

Registration information providing different information can be included

Reliability / Operations

Survivability

Built-in Test Feature

Aural / Visual Monitor

Transmitter

Non-beacon False Alerts

Coverage

Capacity

Only work in 10–20% of crashes

None

Yes (TSO-C91a)

75 milliwatts

Yes (approximately 70%)

Regional

Growth Limited

Expected to work in over 60% of crashes

Yes – Increases reliability

Yes

Watts

None

Global

Room For expansion

*See Appendix A for an explanation of each Feature.

What is meant by “Phase-out of 121.5 MHz”?

The phase-out of 121.5 MHz refers to the termination of satellite processing of 121.5 MHz signals. It does not mean the elimination of the use of the frequency or emergency beacons operating in that frequency band.

Why did we ever have 121.5 instruments on spacecraft if the system is so unreliable?

Studies were initially conducted by NASA to apply space techniques to the problem of locating ELTs and EPIRBs. Since existing beacons only transmitted on 121.5 MHz, space hardware was developed to relay those signals. It was known back then that there were serious problems with using this band. Besides the fact that there were non-beacon users in the band, it was known that the unstable 121.5 MHz signals would not provide accurate locations. At the same time a new channel was also being developed at 406 MHz. However, 406 MHz beacons were not commercially available at that time. The 406 MHz system was specifically designed for space use and used proven space application techniques such as with the Argos/DCS program.

Will new 406 MHz beacons have 121.5 MHz homers after the phase-out?

Beacons that transmit at 121.5 MHz can provide an alerting function and a homing function. 406 MHz beacons can continue to have 121.5 MHz homers. The phase-out only affects the satellite alerting capabilities of 121.5 MHz emergency beacons.

Why did Cospas-Sarsat select 2009 as the date that they will terminate 121.5 MHz satellite alerting services?

This date was chosen for three reasons. The main reason was that ICAO determined that the earliest Cospas-Sarsat should phase out 121.5 MHz satellite processing was 2008. The second reason was to allow national administrations, ELT manufacturers and aircraft operators time to plan and prepare for the termination of 121.5 MHz satellite alerting, and possibly transition to 406 MHz beacons or other alerting systems. It was felt that waiting until 2009 would also allow the marketplace to adjust to the termination of 121.5 MHz satellite alerting without undue cost to the manufacturers or general aviation aircraft owners. Finally, 2009 was selected as after that time there would not be enough satellites in orbit to reliably locate 121.5 MHz beacons.

If satellite alerting is terminated then how will alerting take place for 121.5 MHz emergency beacons?

Probably as it took place prior to the use of satellites. When 121.5 MHz emergency beacons were first mandated for use in 1970, there was no satellite alerting capabilities. Detection relied on over flying aircraft or passing ships that were monitoring the 121.5 MHz band.

What happens for those aircraft operating in remote areas which have limited over flights?

Although, the carriage of 406 MHz ELTs is not mandated, it is essential that aircraft operating in remote areas begin carrying 406 MHz ELTs immediately. Pilots operating aircraft in remote areas such as Alaska and northern Canada need the advanced technology of 406 MHz ELTs more so than their counterparts operating in the mid-latitudes. This is due to the severe weather experienced in these areas.

The use of 406 MHz ELTs allow SAR forces to respond quicker and this time difference between the 406 MHz and the 121.5 MHz systems will grow if other countries such as Russia decide not to carry 121.5 MHz instruments on their satellites.

Some 121.5 MHz emergency beacons also transmit on 243.0 MHz, will this frequency also be phased-out?

Yes. The 243.0 MHz frequency band is primarily a military distress frequency. Distress signals at this frequency work in the same manner as distress signals from 121.5 MHz emergency beacons. Therefore, they have the same disadvantages. The United States Department of Defense has stated that the satellite alerting of 243.0 MHz is not required. Many military agencies have already begun to replace 121.5/243.0 MHz beacons with 406 MHz beacons.

How are the mandatory ELT carriage requirements affected by this decision?

The existing mandatory carriage requirements (contained in United States Code 49, Section 44712, and in the Federal Aviation Regulations at Part 91.207) which require civil aircraft to carry ELTs are not affected. The regulations still require the carriage of an approved automatic type ELT.

What aircraft on international flights are required to carry 406 MHz ELTs?

Internationally, ICAO determines the carriage requirements for aircraft that fall under the ICAO convention. Specifically Annexes 6 and 10 to the ICAO Convention on International Civil Aviation address operation of aircraft and aeronautical telecommunications. Annex 6 contains information on which type of flights are required to carry ELTs. All airplanes operated on long range over water flights, as well as those on flights over designated land areas are required to carry at least one ELT and in some cases up to two ELTs. Annex 10 contains details on the technical specifications of the 406 MHz ELTs.

Will the Federal Aviation Administration (FAA) reconsider the mandatory carriage requirements?

Congress imposed the current mandate to carry ELTs. Therefore, the FAA cannot remove the mandate. Any changes in carriage requirements must go through, or come from, Congress.

Why not improve the existing 121.5 MHz beacons?

The idea of improving the existing 121.5 MHz beacons was addressed in the 1980s. Improving the frequency stability, encoding identification information^{^[3]}, and increasing the power of the beacons could improve the effectiveness.

By 1985 the Cospas-Sarsat program had reached a critical juncture; either continue forward with the superior 406 MHz system which was already operational, or change the focus to the 121.5 MHz system. It was decided to continue forward with the 406 MHz system for the following reasons:

• any improvements to the 121.5 MHz system would still be available only at a regional level, as the space segment would have to be modified to provide global coverage;

• modifying the space segment was not desirable from a program perspective as international agreements, spacecraft design, and the ground segment would all have to change;

• some States had already begun the use of 406 MHz beacons, and it was felt that a market would develop which would lower the cost; and

• no experimental work was completed to demonstrate the capabilities of enhanced 121.5 MHz beacons.

An improvement to the 121.5 MHz system would result in a beacon similar to a 406 MHz beacon (and costing about the same) that operated in the inferior 121 band. The system would still be faced with interference in the band (the 121 band is an aeronautical emergency band, whereas the 406 band is dedicated to satellite emergency beacons).

What is the difference between TSO-C91, TSO-C91a and TSO-C126^{^[4]}?

TSO-C91 was the original standard, developed in 1970, to which ELTs in the United States were manufactured (RTCA document DO-147 titled “Minimum Performance Standards for Emergency Locator Transmitters” contains the details of the requirements).

TSO-C91a was the follow-on to the TSO-C91 standard. RTCA document DO-183 titled “Minimum Operational Performance Standards for Emergency Locator Transmitters” contains the detailed requirements for TSO-C91a ELTs. The TSO-C91a standard was formally implemented in 1994^{^[5]}. TSO-C126 is the standard for ELTs that transmit in the 406 MHz band. ELTs manufactured to TSO-C126 were allowed for general use starting in 1992.

Why was the TSO-C91a standard developed? What is the difference between TSO-C91 and TSO-C91a

There were two major problems with ELTs manufactured to the original TSO-C91 specification:

• ELTs failed to operate when they should (failed in 75% of accidents); and

• ELTs tended to transmit false alerts (97% false alerts).

Therefore, Congress in 1986 urged that improvements be addressed. NASA (as developer of the satellite system) and the FAA quantified the problem and identified the potential improvements using the TSO-C91a standard. Initial studies showed that the introduction of the new ELTs, along with an effective inspection and maintenance program could improve the success rate for the new ELTs by three times and the number of false alerts could be reduced by 1/4 of the number from TSO-C91 ELTs. The initial studies were further substantiated in 1998 when it was shown that due to the influx of TSO-C91a ELTs, and an improvement in maintenance inspection requirements (contained in the FAA regulation issued in 1994):

• the success rate of ELT activations had reached 60% in 1997; and

• the false alert rate had dropped to 93% in 1997.

How will the 406 MHz ELTs work better?

406 MHz ELTs will work better because they will be manufactured to more rigid specifications which will improve their survivability. 406 MHz ELTs will provide a better position (2-5 kilometers using Doppler technology and 100 meters using GPS technology). The 406 MHz ELTs will provide owner/operator identification information which will allow the SAR forces to respond quicker in a distress situation and expend fewer resources in non-distress situations. Lastly, the 406 MHz ELTs will provide global capability.

What is the difference between fixed and non-fixed (or survival ELTs)?

A fixed ELT is mounted on the aircraft, usually in the tail section, and is designed to be automatically activated on impact. A survival ELT is designed to be carried on board and activated manually. The cost of a manually activated ELT is lower (since there is no requirement to include a complex G-switch), and there are no installation costs (due to the required wiring and instrumentation in the cockpit), which means a lower cost to the owner/operator.

Although not directly related to the issue of terminating 121.5 MHz satellite alerting, this issue has been linked to the phase-out by many people. This is primarily due to the reduced costs. Proponents of survival ELTs also believe that having a manually activated ELT in the cockpit will increase the survivability, and the operation of an ELT in a crash. In order to meet the current regulations (Federal Aviation Regulations Part 91.207), an aircraft owner/operator must have an automatic fixed (AF), automatic portable (AP), or automatic deployable (AD) ELT on board the aircraft. All of these types automatically activate on impact.

What are the advantages of mounting the ELT in the tail instead of carrying it in the cockpit?

The Federal Aviation Regulations state that a fixed or deployable ELT must be attached to the airplane as far aft as possible (tail section). Studies have shown that the ELT has the highest probability of survival in this area.

Why should the user pay more to transition to 406 MHz ELTs?

Aircraft operators have a better chance of being saved with the use of a 406 MHz ELT.

What is the impact of not phasing out 121.5?

Beacon owners will continue to have an inferior level of service and additional lives will be lost. SAR resources will continue to be expended needlessly, and the lives of SAR responders will be jeopardized. Lastly, the shielding requirements for the 121.5 MHz receiver on the satellite may preclude the carriage of the SARSAT package on additional satellites thereby diminishing the level of service for all users.

What is the current status of efforts to terminate 121.5 MHz satellite alerting?

The regulatory, operational, and search and rescue agencies involved in this decision have all coordinated at national and international levels to reach a final position. The figure below describes national agencies and how they were involved in the decision making process.

The Cospas-Sarsat Council at its 23^rd Session in October 1999 decided to phase-out 121.5/243 MHz satellite alerting. The Council decided that 121.5/243 MHz payloads would not be carried on board future satellites starting with the United States NPOESS series of satellites (first launch planned in 2009) and the European METOP-3 satellite (planned launch in 2012). The Council also decided that the Russian Cospas payload will not be carried starting with Cospas-13 planned for launch in 2006. However no data for the termination had been established at that time.

The Cospas-Sarsat Council at its 25^th Session in October 2000 finally decided to plan for the termination on February 1, 2009. Along with this decision, a Phase-Out Plan was adopted. National Administrations and Cospas-Sarsat will use the plan to conduct their phase out related activities till 2009.

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Appendix A

Advantages of 406 MHz Beacons (specifically ELTs)

A.1 Timeliness

A.1.1 Ambiguity Resolution

Two satellite passes are necessary to resolve the ambiguity for 121.5 MHz beacons. However, the ambiguity for 406 MHz beacons can be resolved on one pass. This is due to the improved oscillator stability which allows the system to determine the real location 95% of the time, and due to the ability to determine what type of beacon is activated (e.g., an EPIRB which “plots” on land and in the water is most likely to be in the position that plots on water). This can save up to two hours in responding to the alert.

A.1.2 Waiting Time

The normal waiting time for 121.5 MHz beacons is 45 to 90 minutes (this is how long it takes on average for a satellite to come overhead). Although this figure is the same for 406 MHz beacons when waiting for polar orbiting satellites, the waiting time is significantly reduced with satellites in geo-stationary orbits. The waiting time is typically less than 10 minutes. With identification data [and position data for beacons with GPS input] the rescue forces have immediate alerting [and position information] of the distress.

A.1.3 Store and Forward

Because the 121.5 system is a “bent-pipe” system, mutual visibility has to exist between the beacon, satellite and ground station (the ground station also has to be tracking the satellite) in order for a beacon to be detected. If a ground station does not track the satellite, the signal would be lost until a subsequent satellite passes overhead. This could potentially increase the time it takes to alert SAR forces.

A.2 Location Accuracy

A.2.1 Doppler

The Doppler accuracy of 121.5 MHz beacons is approximately 12-20 kilometers which translates into a search area of approximately 1260 square kilometers. Due to the improved oscillator stability the Doppler accuracy of 406 MHz beacons is generally with 2-5 kilometers which translates into a search area of 13 square kilometers.

A.2.2 Navigational Input (GPS)

If the 406 MHz beacon has a GPS input the accuracy is improved to 100 meters which translates into a search area of approximately less than 1 kilometer. The 121.5 MHz system does not have GPS capability.

A.3 Identification

A.3.1 Nationality and Type

406 MHz beacons are encoded with a country code as well as a protocol code. The country code identifies where the registration information is stored for the beacon. The type (EPIRB, ELT and PLB) of beacon is also coded which provides SAR forces with an idea of the type of distress. This information can also assist the SAR forces in resolving ambiguity.

A.3.2 User Identification

The 406 MHz beacon can also be coded with user identification such as radio call sign, tail number and MMSI. This can further assist the SAR forces in resolving the incident.

A.3.3 Registration

Since each 406 MHz beacon is uniquely coded, detailed registration information can be maintained by national administrations and can assist the SAR forces in determining whether an actual distress is in progress. Detailed registration information can include information about the vessel or aircraft, emergency points of contact and radio gear available.

A.4 Reliability/Operations

A.4.1 Survivability (ELT)

The older TSO-C91121.5 MHz ELTs only survived/activated in less than 20% of the crashes. It is believed that the introduction of TSO-C91a 121.5 MHz beacons, and improved maintenance has increased the survival/activation rate to 60% in 1997. Some of these improvements from TSO-C91a have been carried over to the TSO-C126 standard for 406 MHz beacons. Specifically, the following specifications/improvements will enhance the performance of 406 MHz ELTs:

• requirement for fire survival test;

• shock tests while the ELT is operating;

• operation of ELT during protrusion and pressure survival tests;

• more stringent temperature soak test;

• decompression requirement simulating actual operating conditions;

• requirement to ensure waterproof enclosure after replacing battery.

A.4.2 Built-in Test Feature

A requirement of a built-in test feature ensures that the operator is alerted when maintenance is required (e.g., battery replacement). This will ensure that the ELT works when it should.

A.4.3 Aural/Visual Monitor

TSO-C91 standard for 121.5 MHz ELTs had no requirement for a monitor to detect when the ELT was activated. This resulted in many alerts being generated for hard-landings and other non-distress situations. The TSO-C91a standard called for either an aural or visual monitor. The TSO-C126 standard requires both an aural and a visual monitor. This will help to minimize the number of false alerts to which the SAR forces have to respond.

A.4.4 Transmitter

406 MHz beacons transmit at five watts versus 75 milliwatts for 121.5 MHz beacons. This provides greater reception margin to the satellites and could mean the difference between detection and non-detection for certain types of crashes. The increased power also means that 406 MHz beacons can be detected by geostationary satellites that are in higher orbits.

A.4.5 Non-beacon False Alerts

There is no provision in the 121.5 MHz system to discriminate between real beacon signals and those originating from other sources. All signals located are transmitted to RCCs. Approximately 70% of alerts in the 121.5 MHz band are from non-beacon sources. The 406 MHz system uses a preamble transmitted by the beacon to identify itself as a real beacon. Space and ground processing reject any signal that does not have this preamble. Consequently, only real 406 MHz beacon alerts are transmitted to RCCs.

A.4.6 Coverage

121.5 MHz beacons require mutual visibility between the beacon, satellite and ground station. This is because the instrument on board the satellite can only “relay” the signal, and cannot store it. This limits coverage to those areas located close to ground stations. There are many areas of the world not currently covered for 121.5 MHz beacons. The 406 MHz system uses enhanced instruments that relay signals as well as store them on-board for later re-transmission. This allows the system to provide global coverage. Beacon signals can be stored for over 2 days in memory ensuring that at least one of the many ground stations will eventually recover the signal.

A.4.7 Capacity

The continuous transmission mode of 121.5 MHz beacons limits the capacity of the system. In addition other users in the band also limit the capacity. 406 MHz beacons only transmit a 1/2 second message every 50 seconds. This combined with the random time sharing of the spectrum and frequency spreading can accommodate hundreds of distress signals within view of the satellite.

^{^[1]} NSARC is comprised of agencies from the Department of Defense (USAF), Department of Commerce (NOAA), Department of Transportation (USCG), Department of the Interior (Forest Service), the National Aeronautics and Space Administration and the Federal Communications Commission.

^{^[2]} Detailed analysis of advantages are contained in Appendix A

^{^[3]}A patent (4,888,595) was assigned to NASA (Mort Friedman) for a 121.5 MHz beacon that would include a data acquisition signal and 128 bits of FSK/AM encoded user identification data.

^{^[4]} A complete history of ELT actions is provided at Appendix B

^{^[5]} Although a formal requirement for TSO-C91a ELTs was not introduced, the use of TSO-C91 ELTs was disallowed for new installations and type approval for TSO-C91 ELTs was no longer granted.