The ACC requires digital avalanche beacons

I’m a member of the Alpine Club of Canada (ACC), Vancouver Section, so I get their monthly “Alpine-E-r” newsletter. For the past several months I’ve noticed the following message in the newsletter:

NEW BEACON POLICY The ACC has a new avalanche beacon policy, applicable to all ACC Section and National trips as of November 1, 2011. Single antenna analogue beacons will no longer be allowed on any ACC trip. ACC members are encouraged to upgrade avalanche transceivers to digital, three-antenna models, however two-antenna beacons are still acceptable.

I find this quite disturbing on several levels. To be clear, there is a lot of research that shows that digital beacons are easier to use, and that novice users are much faster, more accurate and successful at finding a buried subject with a digital beacon. This is why most heli-ski operations converted to digital beacons early on — their amateur guests had a better chance at digging out their associates and the professional guides if there was an accident.

However, there is no research that shows that single antenna beacons are inherently less safe.

Avalanche transceiver

DTS Tracker Digital Avalanche Transciever

Safety First

Now, by “inherently less safe” I mean that there is nothing in the design of an analogue beacon that makes it less capable or less safe than its digital counterpart. In fact, single antenna beacons have longer battery life, have much longer ranges, and some tests even show that a trained professional with a single antenna beacon is still faster than a similarly trained person with a digital beacon.

There are issues with the analogue beacons, but as stated above, they are not directly related to the design of the beacon; they are operational in nature. One example is that the analogue beacons are perceived to be harder to learn, and possibly slower at finding a subject. In reality, they may be harder to learn, but when tested they do not prove to be slower in the hands of an expert. Another issue with some analogue beacons is that they can be subject to frequency drift, such that it might transmit outside of its original spec. This affects how easily the beacon can be received by other beacons. This issue is not confined to analogue beacons, and not all analogue beacons use the type of oscillator that is subject to frequency drift.

This brings me to the heart of the matter, and why I find that the policy seems to be out of touch with the reality of avalanche safety.

Any policy regarding avalanche beacons should recognize that the one factor that dominates beacon performance is the expertise of the individual operating the beacon. The second most  important consideration is that the beacon has undergone a function and range check every day of a ski tour, and more than once a day if possible.

User expertise

Modern digital beacons are more complex, both in design and in operation. There are well understood standards for beacon performance, but there are none for operation, and each manufacturer feels free to add options and features however they like. Beacons have become vastly different from each other, such that in an emergency a user is unlikely to be able to use a beacon they are unfamiliar with. Users who feel pressured by this policy might need to borrow or buy a new beacon, but without practise and understanding how the beacon operates this will in fact be detrimental to safety in the short term.

Commercial operations such as heli-ski and backcountry lodges, recognizing this issue, require guests to demonstrate their ability to use the beacon and training is provided. Guests must meet a minimum standard of performance before being allowed to ski.

Beacon Function

I was in charge of purchasing, maintaining and testing avalanche beacons for my SAR team for many years. In that time we’ve used three different brands. We’ve found broken and malfunctioning units in all three brands. I’ve had my own personal beacons fail on two different occasions. These are electronic devices, and they are used frequently, roughly, and in very difficult environmental conditions. They are generally built well, but any unit will fail eventually.

One of the reasons I am so hard on people for bringing smart phones into the backcountry is my experience maintaining a fleet of electronics that is actually designed to be used in the wild, and seeing how they break and fail.

The accepted best practice for beacon testing is that they are tested for both function and range every single day when they are being used. There are three reasons for this:

  1. The beacon may be broken and the test makes sure it’s not, for both transmit and receive functions.
  2. The range check tests the beacon’s batteries, general condition, and compatibility. This takes care of situations where a beacon has undergone frequency drift, has old batteries, is cold (stored outside all night), or has an incompatibility of some other kind (there are examples where digital beacons don’t work as well together as some would lead you to believe).
  3. finally, the check forces the user to visualize the beacon’s search strip, which is the practical distance at which you can reliably pick up another beacon. This also forces the user to begin the day with a safety ritual, much like checking the harness prior to climbing, that puts them in the right frame of mind for dealing with risk.

The Policy

I am very concerned that the notice of the policy change contains no information, or even a link to the justification for the decision. The members of the ACC undoubtedly understand the issues, and are not ignorant of the fact that user training it the most important factor. Perhaps they already have a policy dealing with the function and range checks? Perhaps they also have a policy indicating that trip participants should be tested for familiarity with their beacon? If so I can’t find any links on their web site.

Summary

Objective factors that affect the range of an avalanche beacon:

  • Make of device:
    digital beacons have shorter ranges generally, some devices don’t work well together despite international standards
  • Battery condition:
    Low batteries mean lower range
  • Ambient temperature:
    Colder temperatures mean worse performance for batteries and some electronic components like liquid crystal displays
  • Relative positions of antennas:
    Antennas at 90 degrees have the worst reception
  • Electromagnetic and other interference
    Radios, GPS, mobile phones, and some watches affect reception to various degrees, not predictable

Subjective factors:

  • Ability of user
    is the user able physically (eyesight, mobility
  • Skill of user

The International Commission for Alpine Rescue (IKAR) recognizes that the search strip width determines how fast avalanche debris can be searched, and has repeatedly recommended that manufacturers indicate in the documentation or on the device the expected performance of the device so users can be informed in their selection of a transceiver. In the past (1998) ICAR has even recommended against the use of new digital beacons until issues they detected in their design could be resolved. Quoting from the recommendation:

Therefore, ICAR recommends that equipment employing the tested technology (such as the Arva 8000, Barryvox VX 2000, Fitre Snow Bip II, Ortovox F-1, Pieps 457 Opti 4) should be used for the present as before. Of course, equipment of the older type requires the user to have a good knowledge of the search
techniques and a great deal of practise to get the best out of it.

While these issues have been largely resolved, enforcing that users adopt the newest technology is not always the best practice. Analogue beacons that pass function and range testes are therefore not in themselves dangerous.

The best policy for beacon use will recognize that a combination of checking user skill, and beacon function and range every day prior to travelling in avalanche terrain are the most important factors for avalanche safety. The underlying technology of the beacon is the less important that knowing that the beacon works, and the owner knows how to use it.

References

Edgerly, B. and Hereford, J. Obsolescence and analog avalanche transceivers: Ensuring downward compatibility. Technical report, 2820 Wilderness Place, Unit H Boulder, CO 80301.

Höller, P. and Gibler, F. (2002). On the practical use of avalanche beacons – the austrian transceiver test 2001. In Proceedings International Snow Science Workshop.

Tschirky, F., Brabec, B., and Kern, M. (2000). Avalanche rescue systems in Switzerland: Experience and limitations. In Proceedings International Snow Science Workshop, pages 369-376.

(2008). Recommendation REC l 0007 of the commission for avalanche rescue about the determination by equipment manufacturers of the search strip width to be used with transceivers. Technical report, International Commission for Alpine Rescue.

(1998). Recommendation REC l 0002 of the commission for avalanche rescue of october 3rd, 1998 about avalanche beacons. Technical report, International Commission for Alpine Rescue.

Frequencies and Drift, BeaconReviews.com

Range Test Results, BeaconReviews.com

How to Select the right Avalanche Beacon, TelemarkSki.com

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