Page 7-22
G1000 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
Revision 1
190-00716-01
7.7.4
Procedure B: GRS 77/GMU 44 Magnetic Calibration
NOTE
Procedure A-1 (Section 7.7.2) must first be successfully accomplished before performing
Procedure B, only for situations where the GRS 77 was replaced with a new unit.
Calibration Procedure B must be carried out on a compass rose in order to guarantee
measurements free of environmental magnetic disturbances. Attempting to carry out this
maneuver on a typical ramp area may not yield a successful calibration. The accuracy of
the AHRS cannot be guaranteed if this calibration is not performed on a magnetically
clean compass rose. If the compass rose condition is not known, it is recommended that
the technician follow the guidance in Section 7.7.3.
1.
Start the aircraft engine following the procedures referenced in the appropriate King Air AFM or
AFMS as shown in the General Arrangement drawing, listed in Table 1-2.
2.
After aircraft engine startup, taxi the aircraft to a properly calibrated compass rose.
3.
At the compass rose, align the aircraft to a heading of magnetic north (
±
5°).
CAUTION
Calibration Procedure B must be carried out on a compass rose in order to guarantee
measurements free of environmental magnetic disturbances. Attempting to carry out this
maneuver on a typical ramp area may not yield a successful calibration. The accuracy of
the AHRS cannot be guaranteed if this calibration is not performed on a magnetically
clean compass rose or equivalent.
NOTE
This procedure provides instructions for calibrating both GRS 77 magnetometers
separately. It is acceptable to calibrate both GRS 77 magnetometers simultaneously by
putting both PFD 1 and PFD 2 in configuration mode and following the procedure below,
using PFD 1 to calibrate GRS #1 and PFD 2 to calibrate GRS #2.
4.
Restart the PFD and MFD in configuration mode.
5.
Go to the GRS Page Group on the PFD.
6.
Select the GRS/GMU Calibration page and enter the following softkey password:
•
9
•
10
•
11
•
12 (far right softkey)
7.
Press 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 ENT key after selecting the desired GRS 77
unit to calibrate. The SELECT PROCEDURE field is not blinking.
8.
Using the FMS small knob, select MAGNETOMETER. Press the ENT button.
9.
Use the cursor to highlight the BEFORE CALIBRATION window.
10.
Follow the checklist items displayed on the PFD and press the ENT key as each one is completed or
confirmed. When the CALIBRATE field is blinking, press the ENT key to begin the procedure.
11.
The PFD display advises the operator when to turn the aircraft, when to stop, and when to turn again.
Summary of Contents for Cessna Caravan G1000
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