I interviewed and was hired by FSI at Wilmington, DE. Topics just have to be aviation related. Only guidance I was given and I took was to try to not make it a systems brief. You will be giving your briefing to a bunch of senior instructors, and guess what the last thing is that they want to listen to--another brief about the systems on their aircraft.

Try to make it something they don't normally get--more ops related. Keep it simple and about something you are comfortable with. If it is systems, just focus on one topic, not the entire soup to nuts. All they are looking for is how you can handle speaking in front of a class room. Good luck.