STARTING UP AN ACTUAL DC-9 APU (AUXILIARY POWER UNIT) In my last video, I talked about what an APU (Auxiliary Power Unit) is and showed you an actual APU of a classic McDonnell Douglas DC-9. This time, we sat in an actual DC-9 cockpit (non-flying but operational), and I am here to show you the step-by-step process of starting the APU of a DC-9. Of course, you cannot compare this to an Airbus A320, as the latter is more than a decade younger. Hence, you will notice the procedure to start a DC-9 h