With the availability and affordability of Personal Locator Beacons, 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 on the www.Beacons.org.nz website as well as a here on Wilderlife: When to push the button and what to do next. reproduced from FMC Bulletin – August 2016.
They are held up as an infallible panacea to predicaments; 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 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
During one search, a pair of young climbers found themselves stuck close to Temple Col, Arthurs Pass National Park in deteriorating weather and avalanche conditions.
They elected to dig a snow trench, stay put, and 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 found (albiet 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 which will give you improved peace of mind.
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 it is only a one-way device. There is no way of telling whether or not the rescuers have actually received your distress signal. Rumors abound about new functionalities of future beacons which can give an indication that the signal has been received, but to our knowledge, they aren’t available yet.
There are a couple of Satellite based 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 to respond most appropriately. A huge advantage is communication 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 rechargeable batteries are often less rugged and have more points of failure than a sealed, one-use PLB. Also, these devices rely on private companies notification services, rather than the multinational government supported COSPAS-SARSAT system which PLB’s use.
There is a common misconception that PLB’s are required to be ‘waterproof’. The concept of waterproofness is 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. You can read the detail of the IP scale elsewhere, but it is interesting to note that the highest rating IPx8, is up to the manufacturer to decide, 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 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 a 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 to operate if you activate it, or it will activate without you pressing the button. That’s 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 trip from Gorge Sound to the Stillwater river, then onto the Doon. The group’s satellite tracker was in a jacket pocket during the pouring rain and water must have gotten in. The unit seemed to go bezerk, with random flashing lights, totally out of kilter with the normal indications you’d expect for a normally functioning device. They figured something was wrong, but since it was only a one-way tracking device, they only found out on return 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 of 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 moved a considerable distance whilst paddling down river from where the signal was sent.
The chopper pilot told them the only received a signal from the 121.5MHz homing signal from 10km, and only then intermittently.
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 (it had a see-through 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, albiet 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 the 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 waterpressure 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 can fail more easily if the seal is subject to dirt or debris. These boxes can be 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, actually 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.
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 recent example where a solo tramper fell down a steep gut, and lost his pack (and PLB) during the fall, resulting in a slower than ideal rescue.
In a rescue in the Olivines in December 2018, a group of two got into difficulty 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 one comms device they carried was in the pack they still had, and whilst they waited in soaked clothes, in a tent on a miserable ledge, they contemplated the wisdom of having a comms device on thier 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…