Instruction Manual

Page 4-30 G1000 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
Revision 3 190-00716-01
16. Slowly rotate AHRS1 along the longitudinal (roll) axis to a roll attitude of greater than 5 degrees,
verify the following:
• AHRS2 roll attitude does not change
• An amber “ROL MISCOMP” is annunciated on PFD1 and PFD2
• Autopilot disconnects at approximately 5 deg AHRS1 / AHRS2 miscompare
• The autopilot disconnect audio alert (two hi-low tones) sounds
• A red flashing AP annunciator on PFD1 and PFD2
• Flight director command bars remain in view with autopilot in HDG and ALT mode
17. Replace AHRS1 to normal attitude and verify that attitude display on PFD1 displays current aircraft
attitude.
18. Repeat Steps 13 through 17 for AHRS2.
19. The G1000 Miscompare checks are complete.
4.14 GIA Cooling Fans Operational Check
This procedure will verify that airflow is present from the ported avionics cooling fans to the #1 and #2
GIA units. The fan speed monitoring circuits and annunciations are checked by the G1000 Cooling Fan
Fail Annunciation Check in Section 8.1.4 and a Visual Inspection of the fans and hoses is accomplished
in Section 4.4. This check requires the G1000 to be powered on.
1. Gain access to the nose avionics compartment.
2. Disconnect cooling fan hose from the pilot side GIA and verify airflow is present.
3. Reconnect the cooling fan hose to the GIA and secure using MS3367-5-9 cable tie.
4. Repeat Steps 2 through 3 for the copilot side GIA.
5. The GIA Cooling Fans Operational Check is complete.
4.15 GDU Cooling Fans Operational Check
This procedure will verify that airflow is present from the PFD1, MFD and PFD2 cooling fans. The fan
speed monitoring circuits and annunciations are checked by the G1000 Cooling Fan Fail Annunciation
Check in Section 8.1.4. This check requires the G1000 to be powered on.
1. Remove PFD1 as described in Section 6.1, steps 1 and 2 (Removal).
2. Identify the PFD1 cooling fan and verify airflow is present.
3. Reinstall PFD1 as described in Section 6.1, steps 2 through 4 (Reinstallation).
4. Repeat Steps 1 through 3 for the MFD and PFD2.
5. The GDU Cooling Fans Operational Check is complete.