link attached.

News story of climber with broken leg using a MLU to seek assistance.

<img src="/images/graemlins/cool.gif" alt="" />http://www.oregonlive.com/news/oregonian/index.ssf?/base/news/117021755267400.xml&coll=7

I'm not positive but I believe a MLU will alert authorities if you are in trouble by transmitting a distress signal. I'm pretty sure they use fixed radio towers placed on the mountain to triangulate your location based on this emitted distress signal. Or well thats how the Mt. Hood system has been explained to me in the past.

An MLU is simply a transmitter. In order to be of any use the sheriff/SAR has to be notified to activate receivers/direction finding equipment. (calling 911 will do)

A PLB transmits a distress signal to satellites, providing notification that someone is in distress and the location.

Here is another link regarding a rescue in 2003 on Mt Hood and the MLU.

http://www.traditionalmountaineering.org/Report_MtHood_snowcave.htm

link relating to the MLUs

http://www.kgw.com/environment/stories/kgw_121906_news_locator_units.26bbe60c.html

hope this helps....

<img src="/images/graemlins/cool.gif" alt="" />

Just to clarify: the climber DID NOT use the MLU to seek assistance.

From his interview on the local news station, we learn that he fell, activated the MLU, then saw another climber in the distance. He couldn't stand, and from where he was, the other climber couldn't see him. He waved a jacket or other piece of clothing in the air (on an ice axe, if memory serves) to attract the other climber. It worked.

The other climber came to his aid. The other climber had a cel phone, and called dispatch to report the incident. He was able to describe exactly where they were, and was able to talk in the rescuers.

The MLU played absolutely no part in the location or rescue; my understanding is that the MLU receivers weren't even deployed.