GPS is one-way. Even if your phone could get a signal, it wouldn't be broadcasting to SARSAT (https://en.wikipedia.org/wiki/International_Cospas-Sarsat_Programm

GPS is one-way. Even if your phone could get a signal, it wouldn't be broadcasting to SARSAT (https://en.wikipedia.org/wiki/International_Cospas-Sarsat_Programme https://en.wikipedia.org/wiki/International_Cospas-Sarsat_Pr...). You'd need something like this: https://www.acrartex.com/products/catalog/epirbs-and-accessories/globalfix-pro/#sthash.2Ehnd1FT.2ScMgqFT.dpbs https://www.acrartex.com/products/catalog/epirbs-and-accesso... and even then, that's manually deployed and needs line of sight to the satellite network. I'm not sure why a plane wouldn't have at least a few such devices on board in case of crash (there's no monthly fee or anything). Just under the skin perhaps so they'd only automatically deploy during something catastrophic? I'm sure someone knows.