The Latest in Emergency Location Devices

[John DeRosa]

My first Emergency Location Device (ELD) back in the early 2000's was an Emergency Locator Transmitter (ELT).  Its only function was to transmit a homing signal on 121.5.  Current modern ELTs broadcast a 406 Mhz signal to satellites with encoded GPS location as well as a 121.5 Mhz homing signal.   There is no service plan required to use a ELT.

After the ELT I purchased a series of Personal Locator Beacons (PLB) which over time got small and smaller.  It too broadcasts a 406 Mhz signal to satellites with your encoded GPS location  as well as a 121.5 Mhz homing signal.  There is no service plan required to use it. The downside is it is a one way outbound communications path.

Then I decided to purchase a Garmin InReach Mini followed by the Mini 2.  I'm thinking of trading up to a Mini 3.  Truly a very nice sized portable emergency location device. It broadcasts on 1.6 Ghz to overhead satellites but has no 121.5 homing signal.  This requires a service plan for use.

Full Disclosure - I haven't tried any of the cell phone base satellite communication systems.  Have you?  How well did they work?

HOWEVER, the latest news on the ever forward progress to make emergency location devices as small as possible was announce this month (April 2026) when Garmin integrating their InReach technology into a WATCH!  WOW! 

For more information click here. 

- John (OHM)

http://aviation.derosaweb.net/presentations

[Peter N. Steinmetz]

I have carried a 406 MHz PLB for over a decade now. I have tried the inReach but it did not seem like the locations were very accurate in the mountains. 

My understanding is the systems used by the inReach are not quite as failsafe as the 406 MHz PLBs. But I would be curious to see any more detailed data on this. 

Peter

[Jeff Stetson]

The old 121.5 ELT's are essentially useless. Authorities now no longer respond to them at all, unless there is other evidence of a crash indicating that it's real. These old units are "legal" if already installed, but cannot be resold, reused in another aircraft or repaired legally. The 406 ELT;s are much better but still have a high failure rate. No ELT is required for gliders in the USA.

PLB's are, relatively speaking, great, but most don't trigger automatically. They stay with you, not the plane. They are not to be used if you can contact responders by other means, cell phone, for example.

One personal experience with crash detection available on some phones: Before any club members arrived, a Light Sport flipped over after an early morning landing at our quite rural gliderport ~3 years ago. Rescuers from the local volunteer fire department were on the scene within minutes, called automatically by the guy's iPhone, most likely via the mobile network. The newer Android phones, like my Pixel 10, also have this feature. It must be enabled by the user to be active. Some also can use a satellite connection if the network isn't available.

[Mark Mocho]

One advantage of the Garmin InReach equipment and service is the optional benefit of a dedicated Search and Rescue insurance plan. For $29.95 per year, costs of Search and Rescue are covered, as well as accidental death and dismemberment, some medical and some liability. If you go down in a remote area and need dedicated Search and Rescue services, you don't get hit with associated SAR expenses. This includes helicopter rescue, for example. SAR sometimes can cost you thousands of dollars. Read the policy on the InReach website.

  "Search and Rescue means those reasonable costs incurred for fuel, operating costs, repair and rental of: • motor vehicles; • aircraft or helicopters; • hovercraft; • Unmanned Aerial Systems when operated according to FAA guidelines and regulations; • snowmobiles; ......."

(Partial quote from the SAR Policy)

[Eric Greenwell]

I'm very curious about your accuracy issues, as I always thought GPS units all had similar accuracy - within 50 feet or so, anyway. Which inReach were you using? Do you mean the locations were not very accurate while flying in the mountains with inReach? Or was it when hiking in the mountains? And what did you use to determine the correct locations, and how much error did you notice?

[Peter N. Steinmetz]

this was probably 5 years ago. I was hiking in the Tetons and had the breadcrumbs on and the device set so my wife could see where I was. 

It actually had me being at one point in a completely different canyon and another time about 1 mile up a trail in a canyon instead on the mountainside along it. 

It was very strange and I decided it just was not worth the subscription. Sorry that is not a more precise sort of measurement but I just lost interest after seeing that. 

Peter

[Mark Mocho]

Peter-

Were you referencing the GPS location against a map? What was the publication date on the map? What Earth model was the map modeled from? Was the GPS coordinate format set correctly? (DD.DDDD, DD.MM.MMM, DD.MM.SS.S) I am willing to bet that the InReach information was correct, and you were misinterpreting the correlation to the map coordinates. It is also possible that the map was incorrect. I have used GPS as far back as 1994 for hang gliding contests and while "Selective Availability" (a purposeful "skewing" of the position information) sometimes gave a position error of up to a mile and did not agree with published maps, it was much more reliable than your account suggests. "Selective Availability" was discontinued May 2, 2000, by an Executive Order from President Bill Clinton. After that, I had no problems correlating GPS information with maps published within a few years and were using the WGS84 Earth ellipsoid model.

GPS positioning is extremely accurate. The math used is calculated to 17 decimal places. I find it hard to believe that any modern GPS device could exhibit errors of such magnitude unless the map was out of date or egregiously incorrect (possible with older maps or maps from sources other than the USGS.)

If you are interested in GPS and its origins and development, I highly recommend a wonderful documentary available on YouTube about how the original GPS principle was conceived during the flight of Sputnik in 1957, when the position of the satellite was determined by its radio signal. Somebody (watch the video) made the observation that the signal itself could be mathematically reversed to provide the position of the receiver on the ground. And that's how it all started.

The Story of GPS: "The Lonely Halls Meeting" Full Documentary 

[Peter N. Steinmetz]

Mark,

I actually did assume it might have something to do with being in the mountains. Since that was my primary use case for this device, I lost interest in it. 

I think that does overlap a bit with what is being discussed here in this thread, namely, devices to find one in an emergency. A plane crash could be in mountainous terrain, though perhaps the location of the crash is less likely to cause interference than when hiking and climbing. IIRC though, this was a fairly open canyon, one of the bigger ones in the Tetons, though a canyon surrounded by mountains certainly. 

Thus I trust the other PLBs more to function and let people known there is a problem in an emergency and perhaps get an accurate GPS fix out. They don't let you send messages which is a downside for many people. Though it was actually one of the reasons I agreed reluctantly to start carrying one in the first place while climbing as I go into the wilderness to get away from all that sort of thing.

And yes, normally GPS is very accurate. My dislike of them for an emergency locator beacons is not related to that. 

Peter

[Peter N. Steinmetz]

Though thinking about this more, I am now wondering if for glider and airplane use, versus mountaineering use, an inReach or similar device would be a better choice than a pure PLB?

In this use case the deliberate isolation aspects do not apply and the odds of it being in a canyon and unable to provide an accurate fix seem lower.

Does anyone know how well they work in flight? I was meaning to test that.

[Mark Mocho]

It is true that GPS receivers can sometimes be less reliable in steep, mountainous terrain (or even in heavy tree cover) due to their occasional inability to "see" at least four satellites. Three satellite signals will give a position (2D), and a fourth will provide elevation (3D). In open terrain, seven satellites are often in "view." The more satellite signals you get, the more accurate the position. In the "early" days of GPS, there weren't enough operational satellites to provide full coverage over the entire globe. (Or pizza for you Flat Earthers).  As of 24 April 2026, 83 Global Positioning System navigation satellites have been built: 31 are launched and operational, 1 is undergoing commissioning, 7 are in reserve or testing, 41 are retired, and 2 were lost during launch. Receiver technology has matured to the point that even poor reception problems have largely been eliminated. The biggest problem facing us right now are jamming and "spoofing." Here at Moriarty, we occasionally have to deal with loss of service caused by military testing and simulated combat scenarios emanating from the White Sands Missile Range and Holloman Air Force Base. These exercises are scheduled and the dates and times are publicized. You have to pay attention to the schedule, as your flight information and logging can be affected. In one case, we were planning a soaring contest that would have been affected. Our airport Manager, a retired USAF Colonel, was able to negotiate a change in the operating hours of the exercise to permit the contest to be held.

[Moshe Braner]

Moreover, most current GPS receivers listen to signals from other GNSS systems besides the US GPS.  There are European, Russian, and Chinese "constellations" of satellites.  Between that and the improvements in receiver sensitivity, their performance is amazing.  The good ones easily get a fix while indoors, on a seat inside a metal car, etc.

Regarding PLB vs. Inreach etc, the GPS accuracy is NOT an issue for choosing between the systems, since both approaches rely on a GPS receiver in the device to report your position to SAR.  The PLB also offers the possibility of homing on the 406 MHz signal to find you, although that's not as likely to be used.  An important issue is that a PLB has to be manually activated to send anything, and after a crash you may not be able to do that.  An Inreach etc can be set to transmit its position every 10 minutes or so, while flying, and hopefully also after a crash (assuming it is not too damaged, is in an orientation where it can see the sky, etc).  Even if the last transmission is from a few minutes before the crash, it is a lot better than nothing for the purpose of directing the search to the *approximate* location.  Non-satellite communications, such as cell towers (e.g., SeeYou Navigator on your phone) or OGN ground stations (receiving from your FLARM) may yield similar info, unless you are flying in very remote areas.

[*Eric Greenwell1*]

SeeYou Navigator running on an Oudie N with a SIM card will also use the cell towers, but I don't know how useful that would be, compared to it running on a phone. An interesting thought, though.

Eric

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[Ryszard Krolikowski]

I have original InReach for sale.

Like new , $150.

Ryszard

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[Adam Olczyk]

I’ll take it

Sent from my iPhone

On May 3, 2026, at 2:20 AM, Ryszard Krolikowski <ryszard.k...@gmail.com> wrote:



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