Bearhawk wrote:
Could you outline how to connect my Ifly to my ACK 406 ELT? The ELT has the basic cable connections to input GPS data but how does it connect to the Ifly?
Thanks
Sorry to be a little late to the party, but I'd like to comment on this idea. From what I've seen in SAR reports, the doppler data pinpoints the location of a 406ELT accurately enough that GPS data is frosting on the cake. Said another way, GPS is not too imporant. (info: http://www.sarsat.noaa.gov/sys-diag.html)
Conjecture: If the ELT is receiving GPS data from an outside source (no internal GPS), it is probably going to broadcast the GPS coordinates that it most recently received. "Most recently received" might be when the tablet battery died, when the cable was unplugged either deliberately or accidentally, the tablet was turned off, etc. while the airplane continued to move. In that case, the doppler location will still be accurate but the GPS location being broadcast will be ancient history. To furher gum up the works, the GPS data is reported by the geostationary satellites before the low-earth-orbit satellites are able to develop a doppler position solution. So the first location report could be wrong.
Out of curiosity I just called AFRCC and asked about this. The duty officer had seen only one case where the doppler and the GPS didn't match and had not heard of any where the problem was due to old GPS data in the ELT. So probably this is a highly theoretical issue, but for myself I would not make the NEMA hookup from a tablet to and ELT. Little upside, but possible downside.
(For those who are interested the spec is NEMA 0183. Lots of info on the internet, including here: http://aprs.gids.nl/nmea/)