T-45C TS, ADV & IUT ENG-24
GINA Operating Characteristics
INSTRUCTOR NOTES
For purposes of this note, presume the navigation system is
aligned in normal fashion and operated in HYBD mode one (1)
hour. Then, INS mode is selected. Under this scenario two
points should be kept in mind: (1) When INS is selected, GPS
data stops being used. (2) When in INS mode, the Lat/Long
shown on the ACFT display page does not reflect a “pure” INS
solution for position computations. INS, alone, starts affecting
the Lat/Long only from the precise moment INS mode is
selected. Selecting INS does not remove accrued HYBD (INS
and GPS) position errors. In this example, the GPS and INS
both affected present position computations from the time the
GINA completed its ground alignment and entered HYBD
mode, one hour earlier.
3.
GPS
a.
Not a GINA operating “mode”
b.
Selecting GPS on the ADI display does not
change the internal GINA mode of operation
NOTE: GPS is boxed, when selected. That
boxing is accomplished by the DEU. By
contrast, when HYBD or INS are boxed, the
GINA operating mode is actually changed,
accordingly.
c.
Pilot reads a pure GPS Lat/Long position on
ACFT DATA page when GPS is boxed
INSTRUCTOR NOTES
The statement “Not a GINA operating mode” requires
clarification. At no time can INS be entirely deselected from the
GINA navigation process. It is integral to the GINA system,
whatever is selected: HYBD, INS, DGRO or GPS. From a
pilot’s perspective, selecting GPS results in just one significant
effect: i.e., the Lat/Long coordinates shown on the ACFT
DATA page reflect GPS positional information, only.
Original (9-98)
Page 24-31
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