Technical data

Product Specification
HIF-2121/R5 CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 965-1176-601 REV: D SHEET 13
2500
2000
1500
1000
500
0
1000080006000400020000
TERRRAIN CLOSURE RATE (FEET/MIN)
RADIO ALTITUDE (FEET)
"
T
E
R
R
A
I
N
T
E
R
R
A
I
N
"
"PULL UP!"
"TERRAIN
TERRAIN"
"PULL UP!"
FIGURE 1.3.1.2-2: MODE 2B - EXCESSIVE TERRAIN CLOSURE RATE
Mode 2B provides a “desensitized” alert envelope, permitting normal landing approach maneuvering close to the terrain
without producing unwanted alerts. Mode 2B is enabled for three conditions:
• Whenever flaps are selected to the landing position
• If the aircraft is performing an ILS approach and is within ±2 dots of the glideslope centerlines
• For the first 60 seconds after takeoff
If the aircraft penetrates the Mode 2B envelope with either gear or flaps not in landing configuration, the aural message
“Terrain, Terrain” is generated initially, and alert discretes are output for driving visual annunciators. If the aircraft
continues to penetrate the envelope, then the aural message “Pull Up!” is repeated continuously until the warning envelope is
exited. If the aircraft penetrates the Mode 2B envelope with both gear and flaps in landing configuration, the aural message
“Terrain....” is repeated until the envelope is exited.
Envelope modulation, as described in section 1.3.1.7, is used to eliminate, whenever possible, operationally-induced
unwanted warnings.
1.3.1.3 Mode 3 - Altitude Loss After Takeoff
Mode 3 provides alerts when the aircraft loses a significant amount of altitude immediately after takeoff or during a missed
approach, as shown in Figures 1.3.1.3-1 and 1.3.1.3-2. Figure 1.3.1.3-1 shows the turboprop curve, available on MKVI
EGPWS and MKVIII EGPWS. Figure 1.3.1.3-2 shows the turbofan curve, available on MKVIII EGPWS only and selectable
at the time of installation.
.
0
0
250
500
750
1000
R
A
D
IO
A
L
T
IT
U
D
E
(F
E
E
T
)
MODE 3 - DESCENT AFTER TAKEOFF
25
50
75 100
ALTITUDE LOSS (FEET)
150
50
125 175
GPWS
FLAP
925
5 FT/SEC
700
OVERRIDE
"DON'T SINK"
"DON'T SINK"
FIGURE 1.3.1.3-1: MODE 3 - ALTITUDE LOSS AFTER TAKEOFF (TURBOPROP)