Technical data

Product Specification
HIF-2121/R5 CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 965-1176-601 REV: D SHEET 90
6.7.3.1 Terrain Caution and Warning Envelopes
The basic terrain caution envelope (or yellow alert envelope) and terrain warning envelope (or red alert envelope) boundaries
are illustrated in Figure 6.7-2.
FLIGHT PATH ANGLE
TERRAIN FLOOR
(FPA)
WARNING LOOK AHEAD DISTANCE
CAUTION LOOK AHEAD DISTANCE
WARNING LOOK UP DISTANCE
CAUTION LOOK UP DISTANCE
WARNING
AREA
AREA
CAUTION
LOOK AHEAD DISTANCES VARY WITH GROUND SPEED AND DISTANCE TO RUNWAY
TERRAIN FLOOR VARIES WITH DISTANCE TO RUNWAY
SLOPES VARY WITH FPA
SLOPES = GREATER OF FPA OR +6 DEG
FIGURE 6.7-2: TERRAIN CAUTION AND WARNING ENVELOPE BOUNDARIES
A perspective view of the terrain detection envelope is illustrated in Figure 6.7-3.
CENTER TINE
LOOK AHEAD DISTANCE
STARTING WIDTH=1/4 nM
OUTSIDE TINES POINT OUT +-3 DEG
POINTS ALONG GROUND TRACK
PLUS A LEAD ANGLE DURING TURNS
FIGURE 6.7-3: TERRAIN DETECTION ENVELOPE – PERSPECTIVE VIEW