A generic term describing equipment that broadcasts distinctive signals on designated frequencies and, depending on application, may either sense a crash and operate automatically or be manually activated. An ELT may be any one of the following: (a) Automatic Fixed ELT ((ELT (AF)) (b) Automatic Portable ELT ((ELT (AP)) (c) Automatically Deployable ELT ((ELT (AD)) (d) Survival ELT ((ELT (S))