On Friday, June 19, 2015 at 12:52:41 AM UTC-7, wrote:
Anyone out there managed to install a 406 ELT on a standard category C of A glider with the proper paperwork from the maintenance shop? Just wondering because they all seem to have specs for ground plane dimensions that are incompatible with non-metal gliders. The Kannad referred to earlier specifies a minimum antenna ground plane radius of 24 inches for example.

OK I'll play along, what would the "proper paperwork" be here? It should usually be a minor modification, installation of stand alone stuff, not required by regulation in a glider, and with installation requirements not provided for by any regulation. AFAIK the usual "required paperwork" would be a note in the maintenance log.

There is nothing really unique about a 406 MHz ELT... it's the 121.5 MHz beacon withing the 406 MHz ELT that gives the large ground plane and/or plane/awkward large antenna mounting requirement. Almost all installs of any type of ELT I've seen in gliders suck, especially the antenna location/distance from obstructions, ground plane etc.