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.