Technical data

Product Specification
HIF-2121/R5 CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 965-1176-601 REV: D SHEET 92
Color Terrain Elevation
Solid Red Terrain threat area – warning.
Solid Yellow Terrain threat area – caution.
High Density Red
Dots
Terrain more than 2000 feet above aircraft altitude.
High Density
Yellow Dots
Terrain between 1000 and 2000 feet above aircraft altitude.
Low Density
Yellow Dots
Terrain that is 500 feet (250 feet with gear down) below to 1000 feet above aircraft altitude.
Solid Green (Peaks Only) Highest terrain not within 500 (250 with gear down) feet of aircraft altitude.
May appear with dotted yellow terrain when the aircraft altitude is within 500 feet (250 feet
with gear down) of terrain.
Terrain that is 500 (250 with gear down) feet below to 1000 below aircraft altitude.High Density
Green Dots
1
(Peaks Only) Terrain that is the middle elevation band when there is no red or yellow terrain
areas within range on the display.
Terrain that is 1000 to 2000 feet below aircraft altitude.Low Density
Green Dots
(Peaks Only) Terrain that is the lower elevation band when there is no red or yellow terrain
areas within range on the display.
Black No significant terrain.
Low Density Cyan
Dots
(Peaks Only) Terrain elevation equal to 0 feet MSL (requires compatible display).
Low Density
Magenta Dots
Unknown terrain.
1
High density green dots in Peaks mode have a higher density than in standard display mode.
TABLE 6.7-1: DISPLAY COLORS AND PATTERNS
On some Keyed Component Picture Bus (KCPB) terrain displays, an indication of Geodetic Sea Level (GSL) altitude will
appear (unless suppressed by display software). This altitude is the reference altitude for the display and the terrain awareness
algorithm. In the MK VI and VIII EGPWS, this reference altitude is based on internally calculated Geometric Altitude (see
section 6.7.8) and NOT corrected barometric altitude. It represents the aircraft’s calculated true height above sea level (MSL)
and serves as the reference altitude for color coding of the terrain display (see Table 6.7-1). Because it is primarily comprised
of GPS altitude, this reference altitude will often differ from cockpit displayed corrected barometric altitude. This altitude is
not to be used for navigation. It is presented to provide the crew with additional situational awareness of true height above
sea level, upon which terrain alerting and display is based.
6.7.4.1 Background Display
There are two different background Terrain Awareness display modes: standard and Peaks. For both modes the background
display is computed from the aircraft altitude with respect to the terrain data in the digital elevation matrix overlays.
For standard mode, terrain is displayed using colors and shading patterns corresponding to the vertical displacement between
the terrain elevation and the current aircraft altitude. Red and yellow dot patterns indicate terrain near or above the current
altitude of the aircraft. Solid yellow and red colors indicate caution and warning areas relative to the flight path of the
aircraft. High and low density green display patterns indicate terrain that is below the aircraft and within 2000 feet of the
aircraft altitude. Terrain more than 2000 feet below the aircraft is not displayed and the terrain display is typically blank
during the enroute portion of the flight.
The optional Peaks display adds additional density patterns and level thresholds to the standard mode display levels and
patterns. These additional levels are based on absolute terrain elevations relative to the range and distribution of terrain in the
display area. The Peaks display is thus a “merged” display applicable to all phases of flight. At altitudes safely above all
terrain for the display range chosen, the terrain is displayed independent of aircraft altitude emphasizing the highest and
lowest elevations to provide increased situational awareness. This increased awareness can be particularly valuable to the
flight crew in the event of an unplanned descent or off-route deviation and for the purpose of previewing terrain prior to
descent.
The Peaks display includes a solid green level to indicate the highest non-threatening terrain. The standard lower density
green display patterns indicate mid and upper terrain in the display area as well as terrain that is within 2000 feet of the