There was a report a couple of days back of some people being rescued in Kahurangi National Park, having activated a personal locator beacon .
The three women […] had been tramping on the Leslie-Karamean track when they became stranded on Sunday by the rising waters as they attempted to get to the Venus Hut.
After retracing their route, they sheltered at Thor Hut overnight before reassessing their situation. With river levels still rising on Monday morning, the women activated their emergency locator beacon. […]
Rescue helicopter pilot Barry McAuliffe said the women set off the beacon so people meeting them at the end of the track didn’t consider them overdue.
“They were just worried about their deadline at the other end and if they weren’t there at the end then all hell would have broken loose,” he said.
There’s been some criticism in social media about whether this was an appropriate activation. From that description is reads as if they were most likely safe at a hut.
Exact guidelines for appropriate PLB use are ambiguous. The NZ Radiocommunications regulation which grants a general licence for broadcasting signals on 406 MHz  states that it’s only legal to send a signal under that licence if safety of life or property is threatened. The Mountain Safety Council states that PLBs “must only be used in life threatening situations “. Maritime New Zealand’s Beacons page has a lengthier explanation  (abbreviated below):
A distress beacon is an emergency device to be used when assistance is required to ensure the safety of lives e.g. any life threatening situation or when a serious injury has occurred – it is not a taxi service!
Situations can deteriorate rapidly, however, if you are unsure about when to activate the beacon, it is better to activate it and get help – don’t wait until it’s too late!
When considering activating your beacon please remember that carrying out a rescue can be extremely dangerous not just for the casualty but for the rescuers as well, particularly if the rescue is carried out at night or in poor weather conditions. If your situation is not life threatening and you are in a safe and secure position it may be prudent to delay activation of the beacon until daylight or the weather conditions improve.
In other words, the agency that’s mandated as a first responder to PLB activations in New Zealand states that it might be acceptable to activate a PLB if you think the situation may get worse. That makes sense.
The pilot quoted above suggests that the activation was appropriate, and without a full context beyond a media that’s often incomplete and inccurate with this type of thing, it may be worth giving the party the benefit of the doubt. This is certainly a good opportunity to discuss some of the wider issues around PLB activation, though.
Firstly: When does a situation become an emergency if you’re stranded at a hut? Sometimes it’s necessary to wait out bad weather, but huts provide reliable shelter. In a well managed trip it’d be unusual for a swollen river to constitute an emergency whilst in a hut, unless there were other factors.
Maybe a party will eventually run out of food, but that shouldn’t typically happen until after the intended exit date from the trip, especially when time’s been spent stationary instead of moving. Being stuck in a hut can cause a party to become overdue. If a trusted contact were to report someone overdue, though, it’s very likely that the first places a search operation would check before anything else is all the huts near the intended route.
Maybe it’s worth pressing the button if there’s a good weather window, and clear reason to think that there won’t be for a long time in future?
Secondly: There’s a one-way communication issue with Personal Locator Beacons which, I think, is often overlooked when people are criticised.
People are now being told that they’re stupid if they don’t carry a PLB. It’s a message that’s frequently repeated in the media. That stance is fanned by the standard publicity released by official rescue organisations. (I’ve written about this in the past .) It’s common for people to be judged on whether or not they’re carrying a PLB, sometimes even more-so than aspects like preparation, skill and competence to attempt what’s being attempted.
PLBs are an awesome advancement in back-country safety technology. They save lives which wouldn’t have been saved if people didn’t have them, yet the one-way limitation of PLBs creates new scenarios when unusual situations arise. It takes the decision about whether a situation constitutes an emergency away from authorities, and places it in the hands of the person who holds the PLB.
The choice to actually mount an emergency response remains the responsibility of Maritime NZ. Strictly speaking, the authority could decide there’s no actual emergency and refuse to respond, as Police did when the Barker Hut Trio were requesting a helicopter evacuation via the hut’s radio . In practice with PLB’s, though, the only significant information is often that a person has requested emergency help ASAP. Typically the only way to obtain more detail is to actually go there, probably with a helicopter. That’s 90% of the way to actually rescuing a person and probably 90% of the expense, whether or not the rescue was finally required.
I wrote more about this shifting of responsibility into the hands of often-unqualified people in 2013 . On that unusual occasion, Maritime NZ threatened legal action in response to a man’s judgement of his situation as an emergency, but which the authority didn’t agree with, despite apparent inconsistency with any number of previous incidents. The man was later cleared of any wrongdoing .
Prior to PLBs, sending an emergency help message of this nature simply wasn’t a possibility. When problems arose, it would be necessary for a party to either resolve the situation themselves, or find other means to communicate with the outside world. Most commonly available communication before PLBs was two-way (albeit less reliable or less available), whether it be mountain radio, satphone or cellphone. Rather than simply signalling an emergency but providing no further information, a party requesting help would most likely be discussing their situation with another person — typically a radio operator, a friend or a search authority. It’s an important distinction. These methods allow a party to get feedback and advice on their situation, and they also place accountability for launching a search and rescue operation much more strongly onto the shoulders of a person actually qualified to make that decision.
Since PLBs became commonplace in the outdoor community, people who previously had no obligation nor training to actually make a decision about the severity of their situation, nor the appropriateness of rallying an emergency response, are now being told that they must accept that entire responsibility. This is despite not necessarily having the skill to make that decision. Furthermore, the decision must often be made with no help whatsoever, and often under stress.
It should not be surprising that alongside the obvious benefits that come with PLBs, there will be a portion of inappropriate activations. This is the collateral damage of a policy that Maritime NZ and Police have chosen to pursue, where carrying of PLBs is perhaps at times being promoted as more important than learning the skills to both avoid emergencies and recognise them when they occur.
In the back of my mind I wonder if the days of this one-way communication problem with PLBs are already numbered. SEND devices like SPOT  and inReach , which piggyback on commercial satphone networks, already provide various functions that enable two-way communication. By themselves they don’t replace PLBs, though. They’re not fundamentally designed as emergency devices, which is a key distinction, despite having stapled-on features for signalling an emergency via their existing system. In a situation of an actual emergency, they have notable limitations by comparison with genuine PLBs when it comes to signalling that emergency and requesting help. While many people carry SEND devices primarily for their non-emergency features, such as enabling people at home to track one’s journey, many don’t bother. PLBs still have their place.
Maybe what’s more likely to have an impact on PLB use is when regular ubiquitous technology, such as the phones and other devices which everyone carries everywhere, start talking directly to satellites. It mightn’t be too far into the future before everyone’s carrying a device with them which can semi-reliably provide two-way communication through the Google Internet Balloons  or Facebook Internet Satellites , or some comparable system, perhaps from anywhere on the globe.
If and when that’s possible, limited coverage of terrestrial cellphone towers will be less of an issue. Even whilst PLBs are still carried for immediately signaling obvious and urgent emergencies, maybe it will soon be more likely that people will ubiquitously be able to pursue alternative methods of communicating with the outside world, and getting feedback, prior to making that decision.