What exactly is radio navigation? In short, radio navigation is the art of locating your position on the earth by use of radio waves. Radio waves can be used to find direction (bearing), distance (ranging) and also velocity to or from a station.
Why do you have to open the pneumatic crossfeed valves to de-ice the wings? Exactly what does the AC bus cross-tie switch do? And why do the engines only draw fuel from the center tank when all the fuel booster pumps are on? The key to understanding these and many other aspects of your aircraft is studying the schematic drawings for the various aircraft systems. That may sound a little bit dry, but to help you out I have included a Schematics section in the DC-9 Classic Flight Center that gives you live interactive schematic drawings.
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 fourth update for the DC-9 Classic is now available for download. This beta patch updates your virtual cockpit, corrects some sound files, updates the flight dynamics, updates the engine simulation and it also fixes a number of smaller issues with the gauge file.