I think that that's a slightly different "organization" in different services. In the Navy, it is composed of folks with a LOT of TIS. Usually don't need help anyway, but it can be had.

When I was on a WesPac carrier, I believe that the ISSUE revolver was a 4" M&P, but pilots used to carry all kinds of stuff, from .25 autos to Ruger Super Blackhawk. I heard a story about a pilot who kept a .25 in his crotch, thus preventing its detection, and used it to gain access to a critical helicopter ride away from the scene of the crime. I have heard another (helicopter pilot) state that the .38 with tracers was once useful for announcing one's presence when ship drivers were negligently unaware of it. I don't fully understand that, but that's what was reported to me.