Why Emerging Lifesaving Technologies?
Why is a 406 ELT with GPS so much better?
When we started looking at ELTs one fact stood out.
Depending on who you were talking to it is estimated that between 30 and 70% of
all ELT’s fail during a real emergency.
The reason varies and no real long-term study has ever been
done but here are some the causes most often cited:
- Aircraft hit too hard. More than a 3g impact have shown to
damage many of the other manufacturers units by
breaking housing, wire harnesses, switches and antennas come off.
- Aircraft comes to rest in unusual attitudes and the antenna
is masked from satellite or SAR surveillance.
- Aircraft catches fire or lands in water.
- What, then, can be done to make the unit more survivable?
Emerging Lifesaving Technologies looked at this problem and
designed many safety features into the unit. The most common internal failure
appears to be loss of battery power. Some units use off the shelf alkaline
batteries that corrode and dissipate quickly. They are installed like
flashlight batteries and have little if any shock absorption capabilities.
Other batteries have solder tabs that seem to fail in the 3 to 4g range. Still
others have deteriorated over time without any warning to the flight crew.
Emerging Lifesaving Technologies uses only welded tab
battery connections and our internal tests show the connections surviving
impacts over 500g. In addition the specific battery chemistry lends to long
shelf life, no corrosion, and minimal natural decay. Where the FAA minimum is
24 hours, our battery pack has proven to provide over 100 hours of continuous
operation. The battery pack is bonded to the back plate with a shock absorbing
material to prevent vibration damage during normal flight as well as keeping
them in place upon impact. A patented battery life monitoring system is
installed that notifies the aircraft operator if battery power falls below 36
hours of transmission time. This ensures notification well ahead of FAA
minimums that the battery is discharging and needs replaced.
In addition the PC board is mounted on shock absorbers and
all loose wires and connections are sealed with a potting compound to reduce
failures.
Emerging Lifesaving Technologies has tested far and above
the minimum requirements and all of our units are capable of being installed
any aircraft or helicopter (with optional 6-axis g-switch). Low speed, mid
range (250 kts), and high speed (600 kts) antennas are available.
Why is a 406 ELT with GPS so much better?
Upon receiving the initial notification of a 406 ELT
activation, the Cospas-Sarsat Low Earth Orbiting (LEO) satellites utilize
Doppler shift to locate a specific beacon. The satellites pass overhead and
chart their position as they pass over the beacon. Cospas reports that a 1-3 nm
(2-5 km) accuracy on average is determined this way. This makes the search area
approximately 25 sq. nm (65 sq. km) or about 3700 acres large.
The time required to listen to the short message format of a
non-gps enabled 406 ELT and make this calculation using the initial detection
of the orbiting satellites is about 45 minutes with a maximum of 90 minutes.
Subsequent satellite passes every 60 minutes will refine the
position, with a maximum time of 90 minutes for each pass.
A 121.5 homing beacon is then used to narrow the search to
within ¼ mile.
406 ELTs equipped with GPS send long message formats that
include the latitude and longitude within 4 sec (as in degrees > minutes
> seconds) of the location. This gives you an accurate position of better
than 300 feet.
GPS position that is sent on the first burst or initial
alert provides a near instantaneous accurate fix using the US maintained
SARSAT geostationary satellites which monitor nearly the entire globe at any
given moment.
Each 406 ELT sends a specific ID combined with registration
data and point of contact information. This allows for a potential near
real-time immediate launch of search and rescue (SAR) assets to your exact
location. There is no need to wait for the multiple passes of LEO satellites
required to narrow your position to a manageable search area for SAR.
Emerging Lifesaving Technologies 406 ELT with GPS can be
activated while still in the air and send accurate positional data. If for some reason the aircraft was too
damaged to send information to SAR after the incident, this could mean the
difference between rescue and recovery.
Although the internal GPS updates the unit every second,
Cospas Sarsat rules allow the data burst to be only updated every five (5)
minutes. This is prevents a new alarm going off at the MCC (mission control
centers) at every burst.
Easy install 
