User Guide

Airspeed. The Airspeed indicator, on the left side of the HUD, is a vertical strip of numbers like a
tape measure. A stationary dash points to the numbers on the strip, indicating the plane’s current
velocity in tens of knots. Each mark on the tape indicates ten knots of speed. (For example, “35” on
the airspeed tape indicates an airspeed of 350 knots.) There is a “T” above the dash if true airspeed
is displayed, or a “C” if calibrated airspeed is displayed.
Using S toggles the airspeed tape between calibrated and true readouts. True airspeed is your
speed in knots relative to the ground and is therefore a good measure of your speed relative to
stationary objects. Calibrated airspeed is based on the velocity of the air flowing past the plane,
and is thus a more accurate measure of the plane’s maneuverability from moment to moment.
Mach Readout. Just under the airspeed tape is the mach readout. It measures how fast you are
going relative to the speed of sound (Mach 1). Up to a point, the decreased air resistance at high
altitude allows faster speeds and higher Mach numbers.
Heading. The heading of the plane is displayed along the bottom of the HUD as a scrolling
horizontal tape of numbers in tens of degrees from 0 to 35. (For example, “35” indicates 350
degrees.) Each hash mark is five degrees. The caret (V) over the heading tape indicates the direction
of the next selected waypoint. The stationary tick shows your current heading. Note that headings of
0, 90, 180 and 270 degrees correspond to the directions north, east, south and west, respectively.
When heading directly for your next waypoint, the caret will be lined up over the stationary tick. If
the heading for your next waypoint is not currently on the scale, the caret will hold at the far left or
far right end of the tape.
Altitude Readouts. The HUD displays two types of altitude measurements: 1) altitude in feet above
sea level, and 2) altitude in feet above ground level (the distance between your plane and the terrain
you are currently flying over). The altitude readouts are represented by the vertical tape on the right
side of the HUD. Each mark on the tape indicates 100 feet. ”5,5” indicates 5,500 feet. There is a
caret (>) and a long dash mark along the inside of the tape. The caret shows the continuous rise and
fall of ground altitude, as determined by radar. The dash indicates altitude above sea level.
Note: Be very careful to watch ground altitude (>), especially when flying over mountains.
G Force Indicators. Look for the two G Force readouts in the upper left corner of the HUD. The
upper number is the current G force of the plane. The lower number is the maximum G the plane is
capable of. The 9G rating of a clean F-16 will be reduced by external weapon loadouts, drag due to
damage or extended landing gear.
Fuel Warning. The word “FUEL” appears in the center of the HUD when the fuel supply of the
aircraft reaches critically low levels.
Four-G Pull-Up Warning. The HUD displays an “X” and the words “PULL UP” if the aircraft needs to
pull four Gs or more to avoid the ground at any time.
Distance to Waypoint. The distance to the waypoint selected in the Nav Map display (see Pre-
Flight Checklist, p. 41) is displayed in nautical miles on the right side of the HUD just under the
altitude tape. This distance is prefixed with a “D”.
Landing Gear Down Indicator. “GEAR” appears in the upper right corner of the HUD when the
landing gear is down.
Flaps Down Indicator. “FLAPS” appears in the upper right corner when the flaps are down.
Brake Indicator. “BRAKE” appears in the upper right corner when the brakes are on. If the F-16 is
on the ground, “BRAKE” refers to the wheelbrakes. Otherwise, the Brake indicator refers to the
airbrake.
Stall Warning. “STALL” appears in the center of the HUD if the plane is in a stall condition.
Throttle. The throttle setting, ranging from MIL 1 (20% throttle) through AFT 5 (maximum
afterburner), is displayed just below the Mach readout on the left side. Select throttle settings with
the number keys (1-0; 0 is max. afterburner). To cut the engine, hit `.
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