With the availability and affordability of Personal Locator Beacons (PLB), there are few reasons why there shouldn’t be (at least) one in every team that heads into the mountains.

There’s plenty of excellent information discussing how a PLB works, when to activate it and what to do next. Take a look at the the www.Beacons.org.nz website and this other Wilderlife article:  When to push the button and what to do next. 

PLB’s are sometimes held up as a magic solution to any backcountry incident;  press the button and the cavalry will (eventually) arrive and sort everything out.

But there doesn’t seem to be much discussion about beacon failures, times when the device let its owners down, or situations where they have caused confusion for the emergency services.  Thankfully, the lack of anecdotes for failure points strongly towards the general reliability of these beacons, but its worth considering a few of the ways that they have failed, so that you can stack the odds in your favour.

An internal latent failure

A pair of young climbers once found themselves stuck near Temple Col in Arthurs Pass National Park, with deteriorating weather and avalanche conditions.

Inclement conditions on Temple Col

Wisely, they elected to dig a snow trench, stay put, activate their beacon and await rescue.  Although the PLB flashed its lights and made its noise, the signal didn’t go out. The party were eventually found (albeit much later than they would have liked) and the beacon inspected.  It was found that the antennae wire had separated from the circuit board. Although most beacons have a rudimentary self-test function, the self test does not (and cannot) fully test the transmission function of the beacon. So even if your unit does self test correctly, there is a (very very small) chance that the beacon will not actually work.

How can you mitigate that situation?

Get it serviced.

PLB’s need replacement batteries on a regular basis (each unit will state the number of years between replacement) and most of the authorised servicing centers will perform a more thorough beacon test prior to returning your unit.  If the device gets a particularly hard impact, consider getting it serviced to give you peace of mind that it will still work when it has to.

Carry two devices. 

Although weight is a consideration for many, modern electronic communication devices are so light that there is little excuse for not carrying more than one, especially in a group situation.

Consider having one of your devices that can perform two-way communications. 

One of the drawbacks of a PLB is that only communicates one-way. There is no way of telling whether or not the rescuers have actually received your distress signal.  We’ve heard rumours that future beacons will be able to give an indication that the signal has been received, but to our knowledge, they aren’t available yet.

There are a several satellite linked devices, which allow you to text back and forward to the emergency services.  This two-way link to rescue services allows them to best understand the situation and respond most appropriately.

Image result for Inreach

There are a range of two-way satellite communication devices available for outdoors people.

A huge advantage is the ability to communicate when it is not an emergency.  Messages like “The weather is so good, I’m staying an extra day”   “My car is broken down at the road end, can you come get me?”   “I’m fine, but I’m going to be back later”   or  “the river is up, we’re safe in the hut, and will be out when it drops. I’ll keep you informed”   are so incredibly useful to prevent unnecessary concern from loved ones or rescues that aren’t needed.  You can also send messages between some units in the mountains, which could be pretty handy if your group were to split up for any reason: maybe a few from your group want to do a side trip to quickly visit a summit, whilst the rest of the group has a rest at camp or in a hut.

Devices with screens, buttons and user-rechargeable batteries are inherently less rugged and have more points of failure than a factory sealed, one-use PLB. Also, these texting devices rely on private company notification services, rather than the multinational government supported COSPAS-SARSAT system which PLB’s use. Which is why a PLB and a texting device is a superior solution for emergency communication.


There is a common misconception that PLB’s are required to be ‘waterproof’.   The concept of waterproofness is often a bit misleading. Any shell or membrane designed to keep water out has a limit to the pressure it can withstand.  Nothing is ever fully waterproof, there are only degrees of water-resistance.  (Just watch any movie involving submarines….)

Industry has developed a rating scale for “Ingress Protection” or IP,  and you’ll often see smartphones or cameras with something like “IP67” written on them.  It is interesting to note that the highest rating (IPx8), is up to the manufacturer to allocate, provided the protection is for depths “greater than 1m, for more than 30 minutes”.  A quick google of various popular models reveals a range of claims; “Waterproof to 3m”  or 10m or 15m..  So even on a device which says its “waterproof to IPx8”,  you should actually read the fine print to find out the circumstances when it will no longer be protected against water.

So what does this mean to me?

For emergency situations where actual immersion in water is unlikely, and rain is the main issue, then an IPx6 or more rating is quite sufficient.  But things become different quickly if you are a tramper who has been washed away when crossing a flooded river, or a canyoner, kayaker or packrafter in distress.  In environments with powerful currents, the actual water pressure that can be exerted on the unit can easily exceed even the highest IP ratings and enter the unit.

What happens if enough water gets in?

Anecdotes suggest the two likely outcomes are that the beacon will fail if you activate it,  or that it will activate without you pressing the button.  That’s another reason why having more than one device per group is well worth considering.

In December 2018, a group of Packrafters on the classic Hollyford-Pyke loop were somewhat bemused to see a SAR volunteer hop out of the helicopter which landed on the river bank beside them.

The group had begun a several-week holiday with 3 devices;  A satellite tracker and two PLBs.   The first trip of the holiday was a fantastic journey from Gorge Sound to the Stillwater river, then onto the Doon valley.  The group’s satellite tracker was in a jacket pocket during the pouring rain and water had gotten in. Later in the trip, the unit seemed to go bezerk, with random flashing lights, totally out of kilter with the normal indications you’d expect. They figured something was wrong, but since it was only a one-way tracking device, they only found out back in civilization that it had actually failed on day 2 (of an 8 day trip…)

Now they were down to 2 PLB’s for the Hollyford/Pyke trip.   The group stored the PLB’s in the top of their packs, which were then lashed onto the bow of the packrafts.  The thinking was to have them easily accessible in case of emergency, but it appears that hours of waves breaking over the bow of the packraft resulted in water getting in to one of the units, and causing it to malfunction and sporadically activate.

The NZ Rescue Coordination Center only received a few signals from the device, which then went quiet, so they had no choice but to go and investigate.  The owners of the PLBs had registered them which meant the NZ RCC was able to call the groups emergency contact person, and ask about the groups intentions. However, some of the intentions seemed to be lost in translation. At first the SAR team thought the party was on foot so it took extra time to find the group, who had floated a considerable distance down river from where the signal was sent.

The chopper pilot had only received a signal from the 121.5MHz homing signal from 10km, and only then intermittently.

Hollyford Beacon inadvertent activation

When the SAR team arrived, they asked if the group had a beacon. The team pulled out the two they had, and found one of them had a flickering ‘activation’ light, and moisture could be seen inside the units clear case.  They figured that was the faulty beacon, and the SAR team took it away. The group was able to continue on its merry way, now with only 1 (hopefully) functioning device in the party.

After returning home, the group learned that their loved ones had been a little stressed trying to get in contact with one another after the RCC called.   Ensuring you give your loved ones the contact information of nominated single ’emergency contact person’ for a trip will ease the stress during a possible incident.

How can I ensure the unit will be safe from immersion?

The simplest method is to have the PLB inside a drybag. Although dry-bags are far from indestructible, they create a barrier between the unit and the environment, which can reduce the peak water pressure on the unit if/when you end up in that raging torrent.  Just like layering for your own clothing in the outdoors, double dry bagging your PLB isn’t excessive, especially with lightweight dry bags. Even if the water penetrates the outer bag, its pressure will be reduced and the inner bag (and PLB) more likely to resist its ingress.

A number of people advocate for rigid waterproof boxes (Pelican Cases, Otter Boxes etc etc). Whilst these do provide extra physical protection from impacts, they are easy to fasten incorrectly, and the seal can fail more easily in dirty environments.  These boxes are more bulky and are not as light as a drybag, but they are well worth considering in conjunction with a dry bag in activities where water and impact is par for the course.  (Kayaking, Packrafting, Canyoning, Coasteering etc…)

Where to wear your PLB…

Any strategy for risk mitigation is an exercise in compromise.   You assess the likelihood and consequence of something happening, then make your decision appropriately.  If there was an ultralight, indestructible, microscopic, completely waterproof PLB, you’d be mad not to wear it securely on your body at all times. But the reality is that most of us carry them in our packs.

Carrying the PLB on your body is really worth considering if there’s a reasonable possibility of being separated from your pack, your gear or your group in an emergency.   Packrafters, for instance, have most, if not all of their equipment (food, shelter, clothing) within the Packraft itself.  If they take a swim and get separated from their boat, they could loose all their survival aids.  That is why many Packrafters advocate carrying a double dry-bagged stash in their PFD’s which contains a PLB, survival blanket/bag and fire lighting kit.

Some PFD’s have an inbuilt storage pouch, but this one has been sewn on at home.

River crossing whilst tramping is another situation where powerful water and pack separation could be possible.. But if you’re thinking about taking the PLB out of your pack and strapping it to you because the crossing looks that scary, then perhaps you ought not to be doing the crossing in the first place!

Solo travellers should also consider wearing a PLB on them; you could look at one example where a solo tramper fell down a steep gut, and lost his pack (and PLB) during the fall, resulting in much delayed rescue.

In a rescue in the Olivines in December 2018, a group of two got into strife when abseiling down a stream whilst trying to get off the Ice Plateau into the Williamson Rock bivvy. One of the party got into difficulty under the waterfall, and it appears the other quickly went to the rescue on a separate rope – leaving their pack behind on top!  Fortunately the only comms device they carried was in the pack they still had, and as they waited in soaked clothes, in a half-erected tent on a soggy ledge, they contemplated the wisdom of having a comms device on their body, or at least one per person!

There’s quite a few more scenarios on the www.Beacons.org.nz website which are worth considering.  It only takes a few moments of mis-fortune to render the “PLB panacea” worthless…

Update: The Rescue Coordination Center NZ got in contact with us, to thank us for this article, to reinforce a few key messages and add a few points;

  • Buy a beacon that’s fit for purpose. If you could end up in the water, make sure your beacon floats (some small ones sink!)
  • RCCNZ recommends that you carry your PLB distress beacon on your person at all times, so you can access it if an incident happens.
  • Return your beacon to your retailer or supplier if you need to replace the battery or have it repaired. If a distress beacon has moisture in it, often it’s because it has been dropped or someone who’s not the manufacturer has opened it. 
  • Read the instructions on how to operate your beacon. One reason a beacon does not work is because the owner doesn’t know how to operate it.
  • Always register your beacon. Its free and helps RCC do its job quicker and more effectively. www.beacons.org.nz