gahorn wrote:The point I'm attempting to make is.... That ELT performance-expectations are outdated in an ADS-B system.
ELT activation merely notifies authorities that an ELT is activated....for whatever reason... and the system-response for either a 406 OR a 121.5 unit is a telephone call to attempt contact with someone who may, or may not, have anything to do with the flight in question.
That is not an active search and rescue matter, it's a clerical matter, and it makes absolutely no difference on what frequency the ELT transmits to accomplish that.
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With all due respect, that's not true. 121.5 is a low power, passive system. IF (big if) someone happens to detect the signal, all they know is that somewhere in the general area an ELT went off. Then they go through a homing process to find it. In reality they way it usually works is an aircraft is reporting missing, they go to the general area, and then they start looking for the signal. When your 121.5 ELT goes off, NOBODY IS GOING TO CALL YOU. They may start a search, but they don't what they are looking for.
406 is an active system. It pings a satellite which sends a command to a constantly monitored center. Embedded in this signal is a code specific to your ELT. Each code is registered, and when the pull it up they know all kinds of info (based on the form you fill out when you register) such as aircraft type, colors, who to call, etc... This gives the responders a massive heard start on figuring out who, what, when, or where. Thus the biggest difference is actually on the clerical side.
Truth be told, once they get our searching in the general area, other than knowing what they are looking for, there probably isn't that much difference in homing signals (unless you had the GPS hooked up to your 406, in which case it broadcasts last known GPS position). The biggest difference in the 406 is the head start they'll get on that search.
As to your ELT vs ADSB argument, you are correct. A properly equipped and monitored ADSB system could be used to pinpoint a downed aircraft.....or someone who landed in the field in his backyard (like I do in winter...skis are fun!), or someone who's transponder crapped out, or...well you get the point. I'll take my chances with the ELT.
DEM