PLB False Alarms

This article discusses an apparent increase in inadvertent triggering of PLB's, resulting in wasted activity by SAR folks. How prevalent is this?

https://www.wildsnow.com/2323/plb-rescue-beacon-acr/

I stumbled onto this by searching for information on the number/percentage of SAR ops initiated by triggering a PLB. That would be nice to know as well.

My impression, unrestrained by any semblance of valid data or statistics, is that the cell phone probably gets most operations started. Comments?

I suppose stuff like SPOT and cell phones are a low bar for activation. It's hard to imagine how a true PLB like an ACR could be inadvertently activated, though. Not only is the switch protected you also have to unfurl a long antenna. With the Garmin Inreach and Mini the "SOS" button is also under a cap that must be removed, then you have to confirm the SOS.

Apparently several false alarms were caused by a person who thought his PLB was an avalanche beacon, activating it every time he went skiing....Also there apparently is widespread failure to register units....

I am curious because my SR experience was mainly in the pre-pLB era, when overdue persons were reported by a third party....

Note that the linked article is from 2010. I don't have any hard statistics on how common false alerts are, but I do have some anecdotal info. First off, we need to distinguish between unintentional accidental activation of the device, and intentional but unnecessary activation (like the skier in the article). Both happen.

The devices can sometimes be activated by accident. The early InReach units manufactured by DeLorme are somewhat notorious for this. It seems the safety lock was poorly designed and the SOS button could fairly easily be triggered by being jostled around in your pack. There were quite a few cases of this. It happened to one friend of mine, fortunately they quickly realized what happened and canceled the SOS before a rescue was launched. I have personal knowledge of another case where an early DeLorme InReach was activated, and a rescue was launched. However, the search managers noticed that the unit was still moving, in a direction away from safety. Further investigation revealed it was a false alarm, before any SAR teams actually left the staging area. Note that when you trigger an SOS on an InReach, the first thing that happens is that the global alert center tries to send you a message to verify that you are in need of rescue. Of course if the unit is buried in your pack, you might not realize they're trying to contact you! Also note that Garmin has fixed the safety lock on the newer InReach units, and accidental activation doesn't seem to be a problem with these units built by Garmin.

ELTs carried by aircraft and EPIRBs carried on boats also have problems with accidental activation. The ELTs are designed to be activated by G forces when a plane crashes. Occasionally, a hard landing (not a crash) will set one off. Many boats carry EPIRBs in a special bracket designed such that if the boat sinks the EPIRB will float free and activate. Sometimes a boat will take an exceptionally big wave which washes the EPIRB free. Or someone inadvertently knocks it free from it's bracket and it activates. One funny incident I heard about was some time back there was a case in SE Alaska when an EPIRB was activated. It was eventually traced to a barge loaded with garbage, being pulled by a tug. It seems that folks were dismantling an old boat, and tossed the EPIRB into the trash along with other boat parts. Trash in this town gets sent by barge for disposal down in Washington. The EPIRB somehow got turned on in the trash pile on the barge!

I was once at a talk by an officer from the Alaska Rescue Coordination Center. He said when circumstances suggest an accidental activation they will generally spend some time trying to contact the vessel, aircraft, or whomever the device is registered to, in order to verify that it is really in trouble, before launching a rescue. A good reason to keep your registration up to date, whether for ELT, EPIRB, PLB, InReach or SPOT!

The other issue, of course, is when people activate a PLB, InReach or whatever when they aren't really in trouble. Like the skier in the story linked in the OP. Some folks don't seem to realize that these units are for true emergencies. Others may feel like they are in an emergency when in reality they probably could suck it up and self rescue. There have been a few well publicized incidents like this. There was the famous "Yuppie 911" incident in the Grand Canyon some years back. I don't think there are that many truly egregious cases, but it does happen now and then. Like anything else, we do need to educate people on when and how they should use these devices.

Don't use it unless you really need it, but if you need it, don't hesitate to activate it. And keep your registration up to date!

Awesome info, AKSAR! Thanks! You've given me a lot to chew on when I figure out which system to go with.

Somehow I thought AKSAR would have good imput to this topic. Now for part 2....

What percentage of SAR operations are initiated by PLBs. For that matter, what percentage by cell phones from the distressed parties?

Just curiosity, because these electronic devices have changed the landscape considerably, compared to the "good old days"

I wonder which is the biggest nuisance, accidental activations or deliberate activations for trivial things?

+1

You might want to take a look at the Outdoor Gear Lab review of Best Satellite Messengers and Personal Locator Beacons of 2020 Their comparison of devices is worth reading.



I don't have any hard statistics. In the good old days, it seems like SAR callouts were almost always from when a family member called 911 because someone hadn't returned. In most places, most of the recreational activity, and hence the majority of missions are in the "front country", "side country", or "slack country". But many of these areas now have at least some cell coverage, and nearly everyone carries a cell phone. So an increasing number of missions come from the party in trouble calling in directly. My spidey sense is that the vast majority of missions are still initiated from a phone call. Cell calls directly from the party in trouble are becoming more common. But satellite devices (PLB, InReach, SPOT, etc) are also becoming more and more common. Certainly deep in the backcountry, a satellite device is the only realistic option for quickly calling for a rescue. I wish I had a statistical breakdown, but I don't.


Again, I have no statistical data. Up thread I mentioned a talk by an Air Force officer from the RCC. If I remember correctly, he said the majority of activations of EPIRB and ELT were accidental, rather than real emergencies. Sorting those out was one of the major tasks of the RCC. He also said that PLB had a lower rate of accidental activations, because they required a series of deliberate actions to turn on. However, this was when PLBs were the main device, before SPOT, InReach, etc were widely available.

Regarding "deliberate activations for trivial things", that of course is a judgement call. What is a trivial thing to someone of hikermor's experience might be a life or death emergency for someone less knowledgeable or prepared. We can easily point to end members, but there is a whole lot of grey zone in between. Except in really egregious cases, I try to avoid judgment (though of course I sometimes do judge ).

If I ever find any good hard data on these topics I will pass it on.

Thanks! Funny, it took me ten years to realize AKSAR meant AK/SAR!

Thanks you very much AKSAR for your information and views. I thought you would have good info...

In the halcyon pre-cell phone era, when Johnnie's mother made the call, we had "unnecessary" operations as well, finding that Johnnie was just a bit overdue, maybe appreciated a bit of water, etc. but was in no real distress.

Todays situation seems much better. Enhanced communication is almost always a good thing. AKSAR alluded to the Grand Canyon incident - a party activating their PLB on three successive days for trivial situations (the last was a complaint about the spring water tasting a bit too salty). This group was exceptionally clueless and probably would have generated a real emergency had they been left to the tender mdercies of the Grand Canyon.

I suppose that the bottom line is that SAR is generally now more efficient than in the "good old days."

For those who might be considering buying an emergency message system, another good source of info is on Alaska adventurer Luc Mehl's website. Take a look at his discussion of Satellite Communications.

Mehl has been doing some really hard core serious adventure trips. He also happens to be a very modest, friendly, nice guy.