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Emergency Position Indicating
Radio Beacon (EPIRB)
EPIRBS
are for use in maritime applications. There are two types of EPIRB. One
type transmits an analog signal on 121.5 MHz. The other type transmits a
digital identification code on 406 MHz and a low-power "homing"
signal on 121.5 MHz.
The 406 MHz EPIRBs are divided into two categories. Category I EPIRBs are activated either manually or automatically.
The automatic activation is triggered when the EPIRB is released from its
bracket. Category I EPIRBs are housed in a
special bracket equipped with a hydrostatic release. This mechanism
releases the EPIRB at a water depth of 3-10 feet. The bouyant
EPIRB then floats to the surface and begins transmitting. If you own a
Category I EPIRB, it's very important that you mount it outside your
vessel's cabin where it will be able to "float free" of the
sinking vessel.
Category II EPIRBs are manual activation only units. If you own one
of these, it should be stored in the most accessible location on board
where it can be quickly accessed in an emergency.
If you have a
406 MHz EPIRB their signal can be instantly detected by geostationary
satellites. This means that even a brief inadvertant
signal can generate a false alert. To avoid getting a call from the Coast
Guard make sure that when you test your EPIRB you follow the manufacturer's
recommendations carefully. Or, follow these guidelines for
general beacon testing & inspecting procedures.
Also, make
certain that you register your EPIRB. If for some reason your beacon does
activate inadvertently and it is registered, the call you receive from the
Coast Guard will be a friendly one. If it is not registered, it may not be
quite so friendly. More importantly, registration will help rescue forces
find you faster in an emergency and allow you to make an important
contribution to the safety of others by not needlessly occupying SAR
resources that may be needed in an actual emergency. If you need to
register a 406 MHz EPIRB, you can now register
online or you may download a beacon registration form from the
registration website and then fax the form to us at: (301) 568-8649. For any other registration questions,
please call us at: 1-888-212-SAVE
(7283).
All 121.5 MHz EPIRBs, often referred to as Category B (or “Mini B's) are
manual activation units. Although these units do work with the low-earth
orbiting satellite system, they do not work as well as 406 MHz beacons, and
they can not be detected by the geostationary satellites that provide
instantaneous alerting for 85% of the globe. Furthermore, 121.5 MHz beacons
are a large source of wasted effort by SAR forces. Most 406 MHz false
alerts can be resolved easily with a phone call. In contrast, every 121.5
MHz false alert must be tracked to the source using direction finding
equipment. These reasons (and more)
have lead the International Cospas-Sarsat
Program to phaseout 121.5 MHz satellite alerting
on February 1st, 2009. Thus, if you have a 121.5 MHz EPIRB it
will no longer work with the Cospas-Sarsat
Satellites after that date and you will need to make the switch to a 406
MHz EPIRB!
For more
information on the differences between 121.5 MHz Beacons and 406 MHz
beacons click to view a Comparison.
The U.S. Coast
Guard has an outstanding website with even more information on EPIRBs, including some that work through the INMARSAT
System. Click
here to view the Coast Guard
EPIRB Homepage.
Emergency
Locator Transmitters (ELTs)
ELTs were
the first emergency beacons developed and most U.S.
civil aircraft are required to carry them. ELTs
were intended for use on the 121.5 MHz frequency to alert aircraft flying
overhead. Obviously, a major limitation to these is that another aircraft
must be within range and listening to 121.5 MHz to receive the signal. One
of the reasons the Cospas-Sarsat system was
developed was to provide a better receiving source for these signals.
Another reason was to provide location data for each
activation (something that overflying
aircraft were unable to do).
Different
types of ELTs are currently in use. There are
approximately 170,000 of the older generation 121.5 MHz ELTs
in service. Unfortunately, these have proven to be highly ineffective. They
have a 97% false alarm rate, activate properly in only 12% of crashes, and
provide no identification data. In order to fix this problem 406 MHz ELTs were developed to work specifically with the Cospas-Sarsat system. These ELTs
dramatically reduce the false alert impact on SAR resources, have a higher
accident survivability success rate, and decrease the time required to
reach accident victims by an average of 6 hours.
Presently,
most aircraft operators are mandated to carry an ELT and have the option to
choose between either a 121.5 MHz ELT or a 406 MHz
ELT. The Federal Aviation Administration has studied the issue of mandating
carriage of 406 MHz ELTs. The study indicates
that 134 extra lives and millions of dollars in SAR resources could be
saved per year. The only problem is that 406 MHz ELTs
currently cost about $1,500 and 121.5 MHz ELTs
cost around $500. It's easy to see one reason for the cost differential
when you look at the numbers.However, no one can
argue the importance of 406 MHz ELTs and the
significant advantages they hold.
For more
information on the differences between 121.5 MHz Beacons and 406 MHz
beacons click to view a Comparison.
Due to the obvious advantages of 406 MHz
beacons and the significant disadvantages to the older 121.5 MHz beacons,
the International Cospas-Sarsat Program have made
a decision to phaseout 121.5 MHz satellite
alerting on February 1st, 2009.
All pilots are highly encouraged both by NOAA and by the FAA to
consider making the switch to 406!
If you need to
register a 406 MHz ELT, you can now register
online or you may download a beacon registration form from the
registration website and then fax the form to us at: (301) 568-8649. For any other registration questions,
please call us at: 1-888-212-SAVE
(7283).
Personal
Locator Beacons (PLBs)
PLBs are portable units
that operate much the same as EPIRBs or ELTs. These beacons are designed to be carried by an
individual person instead of on a boat or aircraft. Unlike ELTs and some EPIRBs, they
can only be activated manually and operate exclusively on 406 MHz. And
like EPIRBs and ELTs
all PLBs also have a built-in, low-power homing beacon
that transmits on 121.5 MHz. This allows rescue forces to home in on a
beacon once the 406 MHz satellite system has gotten them "in the
ballpark" (about 2-3 miles).Some newer PLBs
also allow GPS units to be integrated into the distress signal.This
GPS-encoded position dramatically improves the location accuracy down to
the 100-meter level…that’s roughly the size of a football
field!
In the United States, PLBs
are now authorized for nationwide use.
This authorization was granted by the FCC beginning July 1st,
2003. (Check out the ‘What’s New @
SARSAT’ for more
information on this recent development.)
Prior to July 1st, 2003 only residents of Alaska had been able to use PLBs. The Alaska PLB Program was set up to test the
capabilities of PLBs and their potential impact
on SAR resources. Since March of 1995, the experiment proved very
successful and helped save nearly 400 lives while generating only a few
false alerts. The success of the Alaska PLB program undoubtedly paved the
way for nationwide usage of these devices.
If you need to
register a 406 MHz PLB, you can now register
online or you may download a beacon registration form from the
registration website and then fax the form to us at: (301) 568-8649. For any other registration questions,
please call us at: 1-888-212-SAVE
(7283).
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