TM 1-1510-225-10
3C-62
During an approach with the gear or flaps
extended, the 300-foot altitude gain function is
inhibited. For altitudes below 700 feet AGL with gear
and flaps extended, the "Pull up" aural warning is
replaced by the "Terrain" aural warning.
(c) Descent After Takeoff (Mode 3).
Mode 3 provides visual and aural warnings for altitude
loss after takeoff or missed approach, before attaining
700 feet AGL. Refer to Figure 3C-34. 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).
(5) Terrain Clearance – Gear Up (Mode 4a).
Mode 4a provides visual and aural warnings for terrain
clearance with gear up. Refer to Figure 3C-35. 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 3C-34. Mode 3 – Descent After Takeoff
