Personal Locator Beacons (PLBs) can be carried during outdoor activities to use in case of an emergency. But are there any guidelines on what exactly constitutes an "emergency"? For example, what about the following situations:

  • You slip and fall on a trail several hours away from the trailhead, breaking several bones and putting you in intense pain. Should you hobble back to the trailhead to call for help or activate the PLB?

  • You are bitten by a rattlesnake, experience symptoms of envenomation, and are several hours away from your car. Do you attempt to hike back and call for help or activate the PLB?

  • While skiing in the morning in an isolated area of a ski resort, you run into a tree and break bones. No one responds to calls for help. Do you activate the PLB or wait until nightfall to see if anyone finds you?

Those are kind of contrived examples, but basically when is it appropriate to use a PLB? If the answers are different for different countries, I'm wondering specifically about use in the US.

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    The bill for a PLB-induced rescue operation can be in the thousands of dollars. If you're in enough danger that the price tag seems worth it, then you should probably feel comfortable pushing the button. Commented Feb 1, 2012 at 19:12
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    In the first two examples, where you're on a trail only a few hours from a trailhead, all you're going to trigger with the PLB is that rangers or SAR volunteers will hike in on the trail, and possibly carry you out on a stretcher. This is not super-expensive, and, more importantly, not dangerous to the rescuers.
    – user2169
    Commented Apr 21, 2013 at 20:36
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    I know this is old but every PLB activation is treated from the beginning as an emergency, as its supposed to be one if someone used the device, the fastest way available to reach the subject is used and unless the weather is too bad to fly an air search is the norm. You can be a few hours from the trailhead and they would scramble a chopper if they have one available and that can reach you way faster than a SAR group on land. Commented Apr 15, 2016 at 19:24
  • Also PLBs are supported by COSPAS/SARSAT, no subscription needed and rescue is free as its a non profit network. SEND devices like SPOT and DeLorme are instead served by for-profit networks like Globastar and Iridium and those require subscription to be rescued. Actual rescue bill as chopper costs etc are asked only if there is no emergency (hoax) or if one has be so negligent to put themselves in trouble or knowingly went were they werent supposed to be and something happened (getting lost hiking at night because you didnt have a light or going in clearly signed avalanche area for example) Commented Apr 15, 2016 at 19:47

6 Answers 6


There are three criteria to be balanced in my thinking on the situation of when and if to activate a call for help to a rescue service:

  1. Do you have the skills and training to extract yourself safely from the current situation? Equally important is your assessment of what other means of communications are likely to be available in the timeframe your current emergency demands.
  2. Will activating the beacon now give rescuers more time to assess the situation or do you have time to delay and avoid occupying scarce and potentially costly responder assets.
  3. How long will it take for your other safety nets to trigger? How many people know where you are and when you are expected back? Will they call the authorities or just assume you are back and forgot to check in with them?

I am not advocating delaying a call for help when life is in danger, but instead to only hesitate when you are comfortable that you can handle the situation or that help is near so you can postpone calling on resources when you don't really need them. Similarly, if you are going to need help, everyone is better off if that request gets made now rather than later.

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    bmike: It also sounds like you are suggesting things that a hiker can do before a crisis situation arises. In particular, training in first aid/safety, knowing the EMT situation in an area you're hiking in, and (most importantly) setting up a communication/check-in network before leaving home. I like your answer, and I think each of these points deserves further discussion on TGO. Commented Feb 7, 2012 at 11:30
  • A nice article from the New York Times titled When GPS leads to S O S expands on the balance between wanting people to ask for help sooner rather than later, but also the drain on rescue personnel for frivolous aid calls in some documented cases.
    – bmike
    Commented Aug 28, 2012 at 14:12

Taking each one in turn:

  1. If the trailhead is several hours away you're not feasibly going to be able to get there on your own with broken bones, and may seriously injure yourself further doing so.
  2. Several hours away normally could turn into a lot longer if you're bitten by a rattlesnake, and again by attempting the hike rather than resting you're going to make things worse.
  3. You're in pain, you've tried to call for help, no-one's come and chances are if you're out there much longer nasties like hypothermia will start to set in.

...So yes, I'd say each of those situations warrants the use of the PLB. Each is a potentially life threatening situation, each requires immediate action and, assuming you have no-one with you and no other means of contacting anyone else nearby, could be deadly unless you get help immediately.

I would guess what annoys the authorities are cases where people activate them when there's really no case of an emergency at all (I had a headache, he pulled a muscle, we're really tired, she has a few minor cuts from this rock), or people landing themselves in danger through being completely stupid (taking no / little water on a long hike in the heat, getting lost, wet and tired and so on.) That's not to say you shouldn't activate it if you find yourself in danger after being an idiot of course, but the powers that be won't be best impressed if you've landed yourself in serious trouble through your own lack of preparation.

In short, if you find yourself in a potentially deadly situation you have no other feasible way out of, I'd say activate it.

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    I don't agree with your implication that you shouldn't activate the PLB if your emergency is due to your having been an idiot. Yes, you shouldn't have been an idiot; but the situation is what it is. Yes, rescuers will be annoyed that you were an idiot; but they won't prefer that you'd let yourself die to prevent that annoyance.
    – ruakh
    Commented Aug 10, 2018 at 0:40
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    @ruakh Hmm, it did read like that, but not intentionally. It was meant to read as "sure, activate it if you've landed yourself in dire straights through being an idiot, but prepare for the rescuers to be a bit hacked off when they get there". I've edited it now to (hopefully) make that clearer.
    – berry120
    Commented Aug 10, 2018 at 8:28

All of your situations look like emergencies, especially if you are alone. I read an article where the National Park Service was angry at use of PLBs because someone climbed a mountain and did not want to down-climb, or they were "tired" but seemed to not have nay other condition that would negatively affect their ability to walk out of the wilderness, or they had a single 1-liter canteen and ran out of water in the desert.

I believe misuse of the PLB is when you didn't do your due diligence or continue trying to solve the problem until you were out of options. I think as long as you are able to walk/self rescue, then do so. You may be asked to foot the bill for any sort of rescue, and that will likely be several thousand dollars. If it's worth 5000 bucks to get help, then you are likely ready to flip the switch.

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    As a note, if you have a PLB, you can buy pretty cheap insurance that will cover the $5000 in a real emergency. Commented Feb 1, 2012 at 17:45
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    I don't know about the US, but where I'm from (Switzerland) the bill can/will be way north of 5000$. In alpine rescue situations involving helicopters and larger search parties the total bill often comes up to several 100k$.
    – fgysin
    Commented Jun 13, 2016 at 12:46

Here is how I would evaluate it.

  1. Are there any immediate life threats?

  2. Are you unable to safely move yourself to a place where you can be rescued, faster than help would arrive with a PLB activation?

  3. Are you unable to manage or stop the life threats on your own?

If the answer to those questions is yes, then I would activate the PLB.

I would define "life threats" as things including, but not limited to the following categories:

  • Breathing Problems
  • Severe Bleeding
  • Heart Trouble
  • Broken Bones (Particularly compound fractures)
  • Shock
  • Hypothermia
  • Poisoning

I've been in the situation of having to decide whether to activate or not. We were on a river trip in Alaskan wilderness, and one of our boats capsized. The two people in that boat got severe hypothermia as they floated down the river for ten minutes. Fortunately due to our training we were able to treat that condition after effecting the water rescue.

Had we not been in a position to remedy the hypothermia, or if there had been other traumatic injuries, I would have immediately used our PLB, with the expectation that help might have arrived within 2-4 hours, given our remote location.


A PLB should be activated when search and rescue is required for an emergency with the danger of serious injury or loss of life, and when other emergency response methods are not available.


Being at fault has nothing to do with the decision. If you are in trouble and cannot extricate yourself without risk to life or making your injuries more serious, you push the button, cost be dammed.

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    I think answers like the one you provide are precisely why the question is being asked. You do mention risk to life and injuries, but only to say "if helping yourself makes that worse." Your actual criteria in your answer is "you are in trouble". There is another question on this site which asks if it should be used when you're miles off-road in your vehicle and a tree blocks you from getting back to the road; the answer to that is "No, don't push the button. Camp and/or hike out. At the very least try to wait a day in your car." After reading your answer someone might be unsure of that.
    – Loduwijk
    Commented Jan 30, 2018 at 20:20

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