190-01639-00
GSU 75 ADAHRS Installation Manual
Rev. 6
Page 5-3
completed will require a repeat of the magnetometer interference test. If new magnetic interference is
detected, it must be resolved and then the magnetometer calibration procedure must be repeated. Wiring or
grounding changes associated with a device located in the same wing as the GMU 44 is a good example of
such a change.
5.3 Calibration Procedure A-1: Pitch/Roll Offset Compensation by Aircraft
Leveling
NOTE
Either procedure A-1 or procedure A-2 is required for all installations. Procedure A-1 is
preferred.
1. Level the aircraft to within
0.25° of zero pitch and zero roll.
2. Initiate the AHRS Ground Pitch/Roll Aircraft Level compensation mode by performing the
following steps:
a) Enter the configuration mode by holding the ENTER key on both displays while applying
power. Release the ENTER key when the words INITIALIZING SYSTEM are displayed on
the PFD and MFD.
3. On the PFD, turn the FMS large knob clockwise until the GSU Page Group is selected.
4. At the GSU Page Group, turn the small FMS to display the GSU/GMU Calibration page.
5. The GSU/GMU Calibration page is protected and requires a keystroke password to perform the
calibration. Press the following softkeys in sequence:
a) softkey 9
b) softkey 10
c) softkey 11
d) softkey 12
6. Press in the FMS small knob to highlight GSU 75 #1. The FMS small knob can now be turned to
select either GSU 75 #1 or GSU 75 #2 for calibration. Press the ENTER key after selecting which
GSU 75 unit to calibrate. The Select Procedure field is now blinking.
7. The FMS small knob can now be used to select which calibration/validation procedure to run.
Select PITCH/ROLL OFFSET, then press the ENTER key. If the PITCH/ROLL OFFSET
selection is still blinking, press the ENTER key again.
8. Follow the checklist items displayed on the PFD and press the ENTER key as each one is
completed or confirmed. When the CALIBRATE field is blinking, press the ENTER key to begin
the procedure.
9. After several seconds, a new checklist appears in the lower half of the PFD. Press the ENTER key
as each item is confirmed. When the CONFIRM AIRCRAFT IS LEVEL field is blinking, press
the ENTER key to continue.
10. The result of the pitch/roll offset compensation is displayed on the PFD. If successful, the AHRS
records the required pitch and roll offsets, informs the operator of a successful conclusion and
returns to normal operation.
11. Press the ENTER key on the PFD to conclude this procedure.
340095
The document reference is online, please check the correspondence between the online documentation and the printed version.
