Let's take a look at the overhead panel! "Hell yeah!", I hear you say. It is after all the nerve center of the aircraft. Nothing goes in the aircraft until you consult the overhead panel first.
The DC-9 is equipped with the Sperry SP-50 Automatic Flight Control System (AFCS), which is a gyroscopically controlled electromechanical system. The DC-9 is an old school aircraft and the autopilot installed in this aircraft is very much old school too. If you are used to flying with modern autopilots, you will find that this autopilot works a bit differently than the other autopilots you may be familiar with.
Failure simulation. This is what in my opinion takes the DC-9 Classic, and all other addons that includes such a feature, to the next level. Usually when you simulate a system in an aircraft, you simulate ON or OFF in a normal state. With failure simulation a system can also be simulated ON or OFF in a failed state. While OFF is usually OFF regardless of state, ON and failed at the same time is where it can get really busy real fast on the flight deck.