The reason I carry a PLB when I fly is that unlike the aircraft manufacturer, I don't expect the aircraft and the attached ELT to remain above water long if a ditching emergency occurs. Being an optimist, when things go wrong I expect them to go very wrong. So I equip myself with all the back-up luck that I can. Redundancy is life.

While on active duty my squadron lost a few aircraft. Of the 22 souls in those aircraft one (1) survived. None of the other bodies were recovered. The one person rescued was located (in the middle of nowhere) by activation of his PRC-90 (243.0 MHz) beacon. That was the first and only signal that came from the aircraft. COSPAS-SARSAT was the evolutionary upgrade from that (now ancient) SAR system. Bottom line -- I carry an ACR PLB in my vest. The system has been tested and proven.