Diamond Aircraft DV 20 E 2022, Airplane Maintenance Manual

Page: 490 / 903

AIRCRAFT
Indicating Systems
DV 20 E AMM
Page 208
15 Mar 2022
31-60-00
Doc # 4.02.25
Rev. 2
B. Install the GRS77 Attitude, Heading and Reference Unit (AHRS)
Detail Steps/Work Items Key Items/References
(1) Install the GRS77 unit:
S
Place the GRS77 on the mounting plate.
S
Install the four thumbscrews that attach the
GRS77 to the mounting plate.
S
Visually inspect the connectors to make
sure that there are no bent or damaged
pins.
S
Connect the connector to GRS77.
Make sure that the orientation is correct.
Torque to 0.15 - 0.18 Nm (22 - 25 lbf-in).
Repair any damaged pin.
Make sure that each side lock is
secured on both sides.
(2) Close the access panel in the aft baggage
compartment.
(3) Close the AHRS circuit-breaker.
(4) Connect the airplane battery. Refer to Chapter 24-31.
(5) Energize the G500 system with GDU 620 in
normal mode.
(6) Verify that the GDU 620 displays valid heading
and attitude within approximately one minute.
Note that heading can remain invalid if
the magnetometer is near a large metal
structure such as a hanger wall or if the
magnetometer is close to a large ground
power cart.
(7) Verify that no unexpected alerts are present. If alerts are present, troubleshoot the
system.
NOTE: If the original GRS 77 is reinstalled, then no software loading is required. This does
not include units that were returned for repair as their software and configuration
files are deleted during the repair testing process.
NOTE: If the GRS 77 Configuration Module is replaced, the GRS 77 must be re-calibrated.