Instruction Manual

Page 7-22 G1000 / GFC 700 System Maintenance Manual - 200/B200 Series King Air
Revision 9 190-00915-01
7.7.4 Procedure B: GRS 77 or GRS 7800 and 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 was replaced with a new unit.
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. If the compass rose condition is not known, it is
recommended that the technician follow the guidance in Section 7.7.3.
NOTE
This procedure provides instructions for calibrating both GRS AHRS separately. It is
acceptable to calibrate both GRS AHRS 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 PFD #1 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. Use the FMS small knob to highlight GRS for calibration and press the ENT key. 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.
12. Upon instruction to turn, taxi the aircraft in a right turn. After approximately 25° to 30° of turn from
the last heading, the PFD display advises the operator to stop the aircraft.
NOTE
Due to the difficulties in executing smooth, accurate turns the PFD may incorrectly
interpret a station and instruct to “HOLD POSITION” prior to full completion of a 30°
turn. If this scenario is encountered, it is best for the operator to ignore the “HOLD
POSITION” command and instead use outside references to complete the approximate