Interviewer: What can you tell me about how a turbine engine operates?
Me: Uhhh...suck, squeeze, bang, blow?
FWIW turbines and piston engines operate on the same principles. The drawback of piston engines, if you want to call it that, is they lack continuous ignition and lose efficency converting vertical acceleration to a rotary movement.
When I was hired by my airline my response about turbine engine theory was pretty much what I wrote. I was flying Chieftains at the time of the interview. While I can't speak for interviewers at any airline I think most of them are merely looking for familiarity with things that you should know based on your experience. If you fly a piston twin you should be able to explain how any system of the aircraft operates and how the backup systems function. If you work for a 135 operation you should be able to answer any question on Ops Specs. For instance can you accept a contact approach? When can you cancel IFR? When is a takeoff alternate required?
In my tech interview with Skywest I was asked to draw a diagram of a turbine engine; explain motive flow; and talk about hydraulic system theory. All my experience was in pistons, but I did study up on turbine engines (The Turbine Pilot's Manual), and I had experience with turbine engines in the Navy.
Unrelated to drawing pretty pictures but I'd suggest you be able to answer any question that starts with "When can you descend/leave MDA/leave DA, etc. And be sure you really know the definition of FAF as it pertains to both precision and non-precision approaches. I have nothing to do with interviews anywhere at any airline but I think those questions are fair game.
I'd also suggest being comfortable with anything and everything that you might see on a Jepp plate or lo-alt chart.
Alright guys, thanks for all the input, I appreciate it. I currently fly a piston and a turbine, so I was trying to figure out whether I would have to diagram a piston and turbine engine, or if they only make you draw turbine engines. There's so much stuff to study for this interview, that I was trying to cut down on unnecessary knowledge such as drawing a piston engine.