GLS-NP is absolutely correct when he says the dispatchers have to be paying attention. When it worked for us, it went like this:
PHI had an Astar crash in New Mexico and the dispatchers actually watched it happen - the map display was tracking the aircraft as it returned to Taos NM and about 5 minutes from base, the track stopped. The dispatchers, who were still based in Albuquerque at the time, then tried to contact the aircraft. Then called the state police, giving them the position next to a nearby highway.
The pilot was picked up and in the Taos NM hospital in about 45 minutes, after walking less than 10 minutes off the mountain. Not too bad - when everyone is paying attention.
Apparently, the S-76 crew was unable to get off the emergency notification on Outerlink. This would probably have helped alert the dispatch center something was wrong.
I have personally tested the emergency function and had PHI dispatchers call within 5 minutes, they also were called from the Outerlink company notifiying them of an emergency signal.
Again, when it works, it seemed to work well.