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.
Stepping into the cockpit of an advanced aircraft for the first time trying to learn how to fly it with nothing to help you out but a manual, or maybe a good tutorial if you’re lucky, can be quite a daunting task.
If you are an experienced simmer the general knowledge of how aircraft work will go a long way, but you’re still going to have your work cut out for you trying to learn a new aircraft. If you are a newer simmer, you may be in for an extremely steep learning curve.
The DC-9 Classic comes with these 6 liveries in the release package: