TM 1-1510-225-10
3B-205
(c) Descent After Takeoff (Mode 3).
Mode 3, Figure 3B-164, provides visual and aural
warnings for altitude loss after takeoff or missed
approach, before attaining 700 feet AGL. When the
aircraft penetrates the warning boundary, a "Don't
Sink" aural warning will sound and the PULL UP
glareshield indicator lights will begin to flash. This
message will be repeated every 0.75 seconds until a
positive rate of climb is established. At this time the
warning ceases but the computer continues to
compare the aircraft's barometric altitude to the
altitude where the initial descent began. If the aircraft
should descend again before climbing to the initial
descent altitude, another "Don't Sink" warning will be
generated based on the original descent altitude. The
warning threshold is when approximately 10% of the
initial descent altitude has been lost. This mode is
active from 65 feet to 700 feet AGL during takeoff or
when either flaps or gear are retracted during a missed
approach from below 200 feet AGL. Above 700 feet
AGL the computer automatically switches to the terrain
clearance mode (mode 4).
(d) Terrain Clearance – Gear Up (Mode
4a). Mode 4a, Figure 3B -165, provides visual and
aural warnings for terrain clearance with gear up. The
terrain clearance mode with gear up is activated upon
climbing through 700 feet AGL after takeoff. When the
boundary is penetrated above approximately 175 KIAS
the "Too Low – Terrain" aural warning will be sounded
and the PULL UP glareshield indicator lights will begin
to flash. When the boundary is penetrated below
approximately 175 KIAS the "Too Low – Gear" aural
warning will be sounded and the PULL UP glareshield
indicator lights will begin to flash. In either case, the
warnings will be repeated every 0.75 seconds until the
condition has been corrected.
Mode 4a is inhibited below 50 feet AGL for any
gear or flap positions.
Figure 3B-164. Descent After Takeoff (Mode 3)
Figure 3B-165. Proximity to Terrain (Mode 4)
