Page 5-4
GRS 77/GMU 44 Installation Manual
Revision L
190-00303-10
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 GRS Page Group is selected.
4. At the GRS Page Group, turn the small FMS to display the GRS/GMU Calibration page.
5.
The GRS/GMU Calibration page is protected and requires a keystroke password to perform the
calibration. Press the following softkeys in sequence:
i.
softkey 9
ii.
softkey 10
iii.
softkey 11
iv.
softkey 12
6.
Press in the FMS small knob to highlight GRS 77 #1. The FMS small knob can now be turned to
select either GRS 77 #1 or GRS 77 #2 for calibration. Press the ENTER key after selecting
which GRS 77 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.
