Linda, Glen and Percy correctly pointed out that an ELT is still required, no matter what and a PLB is not a legal replacement to meet that requirement. You can get a 406 MHz ELT that's as good as a PLB except for being attached to the airplane and being way extra expensive (not good to take hiking).
The 121.5 ELT's are nearly garbage. Your only chance of being rescued with just the old-style ELT is if you can manually turn it on before the crash AND scream mayday on a radio channel where someone is listening to get a real search started right away. JMHO So, I agree that a PLB, or maybe the SPOT, would be a nice idea. The PLB is a standard well supported by the governments worldwide. Spot is not. The big advantage to SPOT is that you can pay extra for the tracking option. If you subscribe to the tracking option and turn it on, the device sends out a signal every five minutes. If you go missing and can't activate the locator, perhaps you can arrange for a friend somewhere in civilization to be checking on you. That friend, when they notice you are missing, can call in the rescue and the SPOT tracking can tightly narrow down the search area. This would probably have let them find Steve Fossett. I'd like to have an easy to slap switch for a PLB in my aircraft. If there's an emergency, I'll turn it on. If I manage a successful emergency landing, I'll turn it off and apologize and thank everyone. Ditto for the ELT manual switch. I'd feel confident with a PLB. With the SPOT, you are depending on the company, as Percy said, to stay in business. One more thing. The SPOT depends absolutely on its GPS receiver. That's the location information source. If the GPS receiver can't get a signal strong enough to self-locate, it can only send out a no-location distress signal. It looks like SPOT uses geostationary satellites and has no way to locate you in the absence of the GPS location information. A PLB can come with or without a built-in GPS receiver. Many of those without their own GPS receiver can connect to an external GPS. But, even if the GPS can't function due to tree cover or whatever, the PLB signal still gets out to the satellite and the low orbit, fast moving satellites can locate the PLB to within a kilometer or less. With GPS, the location can be down to meters. If the passive tracking and getting a friend to start the search in the absence of the distress signal is key for you, then the SPOT wins. Otherwise, I think the PLB wins. Ed Ed Burkhead http://edburkhead.com/Ercoupe/index.htm East Peoria, Illinois ed -at- edbur???khead.??com (remove the ? marks and change -at- to @)
