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The search and rescue group that I have helped with doesnt have a way to dial in on a 406 signal. Maybe there is tech that allows this, but I haven't seen it yet. With 121.5 at least you can home in on it.
As far as satellites go, they have been sending up medium orbiting satellites that aid in 406 signal acquisition and triangulation. The numbers that they were sending up was a fair amount, making one ELT ping fairly accurate.
All that said, all these things still run on an old G switch that may or may not go off. I've had more experience with them not going off then going off for no reason, so I don't have much faith in them.

Yes, geo location using doppler is BETTER with the 406 system than it is with the "legacy" 121.5 system which is no longer in use, by the way.

Nevertheless, that initial ping does not give SAR a very precise location data.

If you KNOW you're going to crash, that's the reason for that little button that all these things require in the cockpit now.....push the button. Again, if your ELT is GPS enabled, it will send a 406 ping to a satellite, with a GPS position. That's going to be good enough for RCC to initiate a rescue.

Yes, water can ground an ELT antenna. That said, I know of a light twin that crashed in a swamp in MN, and was submerged. ELT was still transmitting, though range was seriously compromised. Point is, you never know.

406 is tough to DF because it only sends out a burst transmission every 50 seconds. I don't know if anyone has yet developed equipment that can DF those signals.....hence my concern regarding the Emerging Lifesaving Tech units.

As dogpilot noted, actually locating a downed airplane can be really tough. So, having the ability to DF an ELT, even if you know pretty much where the crash site is, can really shorten up a search.

MTV

mtv wrote:Yes, geo location using doppler is BETTER with the 406 system than it is with the "legacy" 121.5 system which is no longer in use, by the way.

Nevertheless, that initial ping does not give SAR a very precise location data.

If you KNOW you're going to crash, that's the reason for that little button that all these things require in the cockpit now.....push the button. Again, if your ELT is GPS enabled, it will send a 406 ping to a satellite, with a GPS position. That's going to be good enough for RCC to initiate a rescue.

Yes, water can ground an ELT antenna. That said, I know of a light twin that crashed in a swamp in MN, and was submerged. ELT was still transmitting, though range was seriously compromised. Point is, you never know.

406 is tough to DF because it only sends out a burst transmission every 50 seconds. I don't know if anyone has yet developed equipment that can DF those signals.....hence my concern regarding the Emerging Lifesaving Tech units.

As dogpilot noted, actually locating a downed airplane can be really tough. So, having the ability to DF an ELT, even if you know pretty much where the crash site is, can really shorten up a search.

MTV

Yes I agree, especially on the lack of 121.5 on the E.L.T. brand. I'm pretty sure that's why they aren't certified in Canada.

My personal decision (valid for me, and me only) is to go with an inexpensive 406 Mhz ELT, and spend my money on a PLB that I will carry on my person. I will make it part of my passenger briefing to show any passenger how to activate and use it. The combination of the two technologies should greatly enhance our rescue odds.