T-45A UJPT, E2-C2, ADV, & IUT Eng-19
Flight Instruments
LECTURE NOTES
The SAHRS/NGS has a validity output that indicates
when the pitch, roll, and/or heading data is invalid.
This signal drives the OFF flags in the ADI and HSI,
which remain in view as long as the validity signal is
false. The signal also generates a CONTR AUG
caution light, MSTR ALERT light, and tone if the
FLAPS/SLATS lever is set to 1/2 or DN, the airspeed is
less than 217 knots, and the CONTR AUG switch is set
to the ALL position. This condition is latched and must
be reset after the SAHRS/NGS validity becomes true
(watch ADI/HSI flags). All SAHRS/NGS data on the
HUD is blanked while the validity signal is false. The
SAHRS/NGS validity signal can go false for a number
of reasons and is not necessarily an indication that the
SAHRS/NGS has failed. The validity defaults to false if
the SAHRS/NGS has no power, during the initialization
period after power is applied, if a BIT failure is
detected, when the SLV mode is first entered and
SAHRS/NGS is performing a "rapid sync" to the remote
compass transmitter, in the DG mode when the
heading set knob is being used to update the heading,
and when SAHRS/NGS is set to the COMP mode.
B.
Attitude director indicator (ADI)
Sg 3, fr 4
1.
Location: centered on both instrument
panels below HUD/gunsight and above HSI
2.
Function:
a.
Displays continuous aircraft attitude in
pitch, roll, and heading on indicator
ATTITUDE DIRECTOR INDICATOR
sphere
(ADI)
b.
Displays localizer (LOC) and
glideslope (GS) information relative to
the center of an ILS approach antenna
pattern
Page 19-12
(8-03) Original
Previous Page
