TM 1-1510-218-10
3B-62
Figure 3B-23. Ground Proximity Altitude Advisory System Controls and Indicators
(1) GPAAS Circuit Breaker. The GPAAS
system receives 28 Vdc power through a 1-ampere
circuit breaker, placarded GPAAS POWER, located on
the instrument panel.
(2) GPAAS
Switch-Indicator
Lights.
A
switch-indicator is located on the instrument panel.
The upper half of the switch-indicator (yellow) is
placarded VOICE OFF. The lower half is an indicator
(red) only and is placarded VA FAIL.
Pressing the upper (VOICE OFF) switch-
indicator disables the GPAAS voice advisory, and
illuminates the VOICE OFF indicator light.
The VA FAIL annunciator light (red) will
illuminate when the GPAAS fails.
(3) GPAAS Volume Control. GPAAS volume
control, placarded VOL, located on the instrument
panel, controls the audio volume of the GPAAS
advisory/warning
messages
down
to
a
certain
minimum level.
(4) GPAAS Aural Warning Indications. The
following is a list of aural indications. Due to the
possibility of activating more than one condition at a
time, a warning priority has been established. The
highest priority message will be announced first.
If a higher priority item is received after a
message is started, voice annunciation of the higher
priority message shall be announced after a lower
priority message in progress at the end of the
message segment. It will not stop in the middle of a
word. On messages that are repeated three times at
4-second intervals, the priority list will be scanned for
higher priority messages and will insert them in the
interval between the messages. The messages
provided by the system are listed in descending order
of priority as follows:
1. "Two thousand" at 2000 feet AGL.
2. "One thousand" at 1000 feet AGL.
3. "Nine hundred" at 900 feet AGL.
4. "Eight hundred" at 800 feet AGL.
5. "Seven hundred" at 700 feet AGL.
6. "Six hundred" at 600 feet AGL.
7. "Five hundred" at 500 feet AGL.
8. "Check
gear"
will
be
announced
immediately
after
500-foot
announcement if gear is not down.
9. "Four hundred" at 400 feet AGL.
10. "Check
gear"
will
be
announced
immediately
after
400-foot
announcement if gear is not down.
11. "Three hundred" at 300 feet AGL.
