The Hornet OSD plugs directly into the FY-31Ap. The small black boxes look the same but they are not. The smaller box to the left is the Hornet OSD, while the bigger box to the right is the FY-31AP.

It looks a little like spaghetti, but this is how it is wired into the system.

The resulting display should look like this.

If your a fighter pilot this will be completely familiar to you.

Heading tape is along the top, current heading is in the box below with an arrow on either side that points you in the direction of “home.” Home is where you initialized the GPS, presumably where you want the aircraft to return to.

– There is no magnetometer on the FY-31ap so heading information comes from the GPS.

Altitude is presented in Meters on the vertical tape on the right side of the screen.

-There is no Barometric sensor on the FY-31ap so Altitude information comes from the GPS.

Speed is presented in Meters per second on the vertical tape on the left side of the screen.

-There is no pitot sensor on the FY-31ap so speed information comes from the GPS.

Attitude information is presented as a dotted line in the center of the screen.

-The Attitude information comes from the attitude of the FY-31ap  unit so if the Autopilot comes loose, or the attitude is not initialized correctly, you will not receive correct attitude information (do not engage the autopilot if the attitude information is not correct!).