Horizontal Situation Display
The Horizontal Situation Display (HSD) is one of the most important pages available on your MFD. It is a moving-map display of the current horizontal situation around you, showing friendly and enemy aircraft, the route you are flying, the area being scanned by your radar, and many other useful pieces of information. The HSD is used to maintain situational awareness of your present location and of what is happening around you.
You can imagine the HSD as what you would see if you were directly above your aircraft, looking straight down. There are three range rings, each representing one third of the currently selected display range (so for example, if you have selected 15 miles, each ring is another increment of 5 miles. If you have selected 60 miles, each ring is another increment of 20 miles). Your aircraft is in the center of these range rings, and the map is oriented so that your aircraft's heading is straight up. Each range ring has four spokes, representing north, east, west, and south. The north spoke on the innermost range ring is replaced with a solid white triangle, to show you what your heading is.
There are two view positions that the HSD can use. In the default mode (DEP), your aircraft's position and the center of the range rings are depressed to about 1/3rd of the height of the screen. This gives you a better view of what is in front of the aircraft (since you are usually more interested in what's in front of you than what's behind you). In the second view mode (CEN), your aircraft is positioned in the center of the MFD, so that you can see the same distance in all directions. Pressing this OSB toggles between these two modes.
Your HSD range can be either decoupled (DCPL) or coupled (CPL) to the FCR range. If coupled, the HSD will automatically scale so that it shows the same distance as the FCR, and if decoupled, you can manually select the range. Pressing this OSB toggles between these two modes.
Pressing this OSB toggles the current zoom level on the HSD. You can select NORM (normal view), EXP1 (area around your aircraft is expanded), and EXP2 (area around your aircraft is expanded even more).
This opens the HSD control menu (see below).
If this OSB is selected, the HSD will freeze in its current position, and will not turn with your aircraft or reposition itself to keep you centered. This is useful to give yourself a static view of a particular area. Remember to deselect this before you fly off the HSD!
Pressing this OSB will declutter the display, removing some information to make the map easier to read.
These OSBs are displayed on the top two buttons on the left row. Pressing up will increase the range displayed on the HSD, and pressing down will decrease the range. If you cannot increase or decrease the range any more, the arrow symbol will disappear. These OSBs are only available if the range is decoupled from the FCR (see above).
When you press the CNTL OSB on the main page, the OSB configuration changes to allow you to select which information you want displayed on the HSD. Each OSB can be toggled to turn the associated item on/off.
Toggles display of the radar scan area and the "ghost" cursor showing the position of your FCR cursor.
Toggles the display of enemy targets that were programmed into your aircraft's computer before takeoff.
Toggles the display of IFF responses from other aircraft.
Leaves the CNTL menu and returns you to the main page.
LINE 1 - 4
Toggles the display of map information lines on the HSD. Currently LINE 1 is the only line with any information - it shows the FLOT (forward line of troops).
Toggles the display of range rings around your aircraft.
Toggles the display of threats uploaded to your computer from an air data link (such as an AWACS aircraft).
Toggles the display of threats uploaded to your computer from a ground data link.
NAV 1 - 3
These toggle the display of your navigational routes. Only NAV 1 has any information - it shows the flight path for your mission.