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McMurdo rescue beacons pass new tests

The new GPS-enabled EPIRBs and PLBs are accurate to 100 meters under real-world conditions

The new GPS-enabled EPIRBs and PLBs are accurate to 100 meters under real-world conditions

A second round of tests of McMurdo EPIRBs and PLBs has given upgraded versions of the British-made emergency locator beacons clean bills of health, and the organization that did the tests says new stricter standards should improve the performance of all such devices.

In a first round of tests the Equipped To Survive Foundation, a Chandler, Ariz., group, reported that McMurdo’s Precision 406 MHz GPS emergency position indicating radio beacon and Fastfind Plus 406 MHz personal location beacon routinely failed to acquire a GPS location fix under real-world conditions. McMurdo since has upgraded its beacons and offered free upgrades to owners of existing units.

In the latest tests of the upgraded McMurdo beacons and a new ACR Electronics PLB, all provided GPS locations under a variety of real-world conditions, according to ETS director Doug Ritter.

McMurdo’s Precision and Fastfind Plus products and the ACR beacon use integral GPS technology to fix the location of the EPIRB or PLB when it is activated, then send that location with the distress signal. If the device’s GPS fails to fix a location, it goes ahead and sends the distress alert, minus that information. Rescuers still can find the device using Doppler effect measurements from two polar-orbiting satellites, but that can take 45 to 90 minutes longer, and the location is accurate to 2 to 5 kilometers compared to 100 meters with a GPS fix.

Ritter raised the red flag about the performance of some of the EPIRBs and PLBs with integral GPS because they cost more than units without the GPS feature and are supposed to give rescuers a more accurate and more timely location. Based on his most recent tests, he says these units now do what they are supposed to.

“I think buyers of a GPS-equipped EPIRB can be confident that the GPS positioning feature is going to work in the manner in which consumers would expect it to work,” he says. “They are going to get a location.”

He says the tests validate that when they work right GPS-enabled beacons enhance chances of rescue. “The current state of the art in location protocol 406 MHz distress beacons appears to be capable of improving the likelihood of a successful rescue by potentially shortening response times in many likely survival scenarios,” he says.

McMurdo technical director Chris Hoffman says in a press release that Ritter’s findings confirm the company’s own testing. “Our upgraded beacons were rigorously tested prior to their introduction, but it is always good to have independent data from typical real-life situations,” he says. “Both the McMurdo Precision EPIRB and Fastfind Plus PLB performed well over the period of testing, quickly identifying their exact position under simulated arduous conditions.”

Last August, McMurdo — one of the world’s largest EPIRB manufacturers — conducted independently witnessed tests of both its upgraded and original specification beacons in response to Ritter’s reports of the devices’ shortcomings. McMurdo managing director Gary Mullins said then that the upgraded unitsperformed “faultlessly,” and theoriginal-specification units performed significantly better than Ritter had reported. Ritter stands by his findings concerning the original-spec McMurdos and recommends anyone owning one to upgrade it.

Ritter says the new ACR unit that passed ETS’s real-world tests was the PLB-200 PLB, marketed as the AquaFix 406 GPS I/O P-EPIRB, TerraFix 406 GPS I/O PLB and AeroFix 406 GPS I/O P-ELT.

Ritter says just as encouraging as the performance of the upgraded McMurdos are the steps regulatory agencies have taken to tighten the performance standards of GPS-enhanced beacons since he made his initial findings public. “There have been some significant revisions to the international standards that address some of the shortcomings that became apparent after the first tests,” says Ritter, whose non-profit organization does consumer research into survival technologies.

COSPAS-SARSAT, the international regulatory agency for search and rescue, is requiring manufacturers to do some testing of the beacons’ GPS feature that better replicates real-world conditions, he says. It also is reducing the maximum time for GPS to acquire a fix from 30 minutes to 10 minutes and is requiring that the 121.5 MHz homing transmitter in a unit be designed so that it doesn’t interfere with the GPS.

Ritter expects the Radio Technical Commission for Maritime Services, the U.S. agency that sets beacon standards, to adopt even more changes to tighten the performance standards.

“I have been pleased by the unexpected quick response of the international community to our findings,” he says. “These revised standards represent a noteworthy philosophical shift on the part of COSPAS-SARSAT and go a long ways toward ensuring that these beacons will work as expected when lives are at stake.”,,