Robinsons R66 - 97-14 LRU Installation - GMU 44 Magnetometer

Page 97.4 Chapter 97 Avionics MAY 2015
97-13 LRU Installation – GRS 77H AHRS (continued)
E. Scheduled Maintenance and Inspections
Refer to Garmin G500H EFIS Maintenance Manual, Section 5 Periodic Maintenance.
F. Special Maintenance and Inspections
1. Turn battery & avionics switches off. Open circuit breaker panel, hinge left seat
forward, and remove F950-3 cover assembly.
2. Inspect condition of and verify no obvious damage to Garmin GRS 77H AHRS,
circuit breaker, and wiring. Verify no loose, chafed, or broken wires or terminals.
Verify no evidence of arcing. Verify equipment security.
3. Secure circuit breaker panel. Perform ground checks per Part D steps 4 thru 6.
97-14 LRU Installation – GMU 44 Magnetometer
Refer to R66 Illustrated Parts Catalog (IPC) Figure 97-13.
A. Description
The GMU 44 magnetometer senses the earth’s magnetic field. Data is sent to the
GRS 77H AHRS for processing to determine aircraft magnetic heading. This unit
receives power directly from the GRS 77H and communicates with the GRS 77H using
an RS-485 digital interface.
B. Schematic
Refer to MM Figure 98-11 for GRS 77H AHRS Installation electrical schematic.
C. Removal
1. Turn battery & avionics switches off and pull out EFIS (5 amp) circuit breaker at
panel.
2. Remove tailcone cowling per § 53-23.
3. Supporting GMU 44 magnetometer, remove hardware securing magnetometer to
F950-4 bracket.
4. Remove MS21919WDG12 clamp and disconnect magnetometer harness from
F951-1 harness assembly at connectors. Remove magnetometer.