Garmin G5 Maintenance Manual page 22

3) What exactly was the aircraft doing in the two minutes that preceded the failure (taxiing on the
ground, flying straight-and-level flight, turning, climbing, etc)? If the problem occurred on the
ground, was it within 100 feet of a hangar using GPS repeaters?
4) How long did the failure last? Was it brief or sustained? If it was repetitive, about how many
times did it happen? Did it happen on more than one day?
5) Was the problem correlated with a specific maneuver or a specific geographic area?
6) Can the problem be repeated reliably?
7) Did the onset of the problem occur shortly after a software upload to the G5?
8) Was there a loss of the GPS position lock?
5.1.3 Air Data
If the airspeed and/or altitude is failed and shows a Red-X condition:
1) Inspect the pitot/static plumbing integrity.
2) Inspect the pitot/static ports and all associated equipment.
3) If the problem persists, replace the G5 with a known good unit.
5.1.3.1 Air Data (Installation with a GAD 13 and GTP 59 Installed)
If the OAT, TAS and WINDS annunciations show a Red-X condition:
1) Inspect GTP 59 OAT probe and connections for faults.
2) Replace the GTP OAT probe.
3) If the problem persists, replace the GAD 13 with a known good unit.
5.1.4 Heading Information (Installations with a GMU 11 Installed)
If a Red-X (steady or intermittent) is displayed in the heading field on the G5, check the following while
the aircraft is on the ground:
1) When taxiing, heading performance is susceptible to the presence of magnetic anomalies (metal
buildings, underground steel culverts, steel grates in the ramp, rebar). Localized sources of
interference on the ground may consistently cause a Red-X to be displayed on the heading in the
same spot while taxiing, and this is not caused by a failure of the GMU 11 or its calibration.
2) Check to see if any new equipment has been installed on the aircraft. If there has been, conduct
the magnetic interference test in Section 7.8.1 to see if the new equipment is causing magnetic
interference with the GMU 11.
3) On the G5 in configuration mode, select the Device Information page, select MAG and verify
there is a Green Check by MAG. If there is a Red-X by MAG, proceed to the next step.
4) Inspect and verify the CAN Bus wiring between the G5 and GMU 11.
a. With power removed, remove a connector from one of the devices that is not located at
either of the extreme ends of the CAN bus.
Garmin G5 Electronic Flight Instrument Part 23 AML STC Maintenance Manual
Page 14 of 54
190-01112-11
Rev. 7