Garmin GI 275 Mini EFIS Close Call Canada

[rjtjrt]

A very close call involving use of Garmin GI 275 mini EFIS.

https://www.tsb.gc.ca/eng/rapports-reports/aviation/2021/A21P0001/A21P0001.html

[Teddy Robinson]

Good grief.

That is as near to an accident as makes no odds.
Partial panel flying is becoming a lost art as avionics improve, but as this demonstrates, when the shiny panels go blank you still have an aeroplane to fly.

[rjtjrt]

IFR, out of control, with 23,000fpm descent then 8,500 rpm climb at times, and aircraft’s airspeed varied from a low of 43 knots indicated airspeed (KIAS) to a high of 242 KIAS, exceeding the aircraft’s never exceed speed by approximately 70 knots.
https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/1331x742/0323d7b9_1b24_49c3_b18a_3415b5776dcd_3eee58501d147a22978b8a7 0dc674d7331510c74.jpeg

[C2H5OH]

Which part of the panel should have allowed for a safe conduction of flight in IMC?
When a standby ADI or HSI detects a fault from a compatible interconnected unit, it will automatically switch to reversionary operation mode, which means it “exclusively behaves as a Primary ADI unit until the fault is resolved.” This mode can also be manually selected from a panel-mounted switch.

When a unit is configured as a primary HSI and a fault occurs with an interconnected unit, it will not automatically switch to reversionary operation mode. In addition, the pilot cannot manually select the ADI display page because it is not one of the pages available when the unit is configured as a primary HSI. Pages available for a primary HSI configuration are HSI and HSI Map; pages available for standby ADI and standby HSI include an ADI page.

In July 2020, the occurrence aircraft’s directional gyro was removed and a Garmin GI 275 MFI was installed in accordance with U.S. Federal Aviation Administration Supplemental Type Certificate (STC) SA02658SE. This MFI was configured as a primary HSI. In October 2020, the aircraft’s attitude indicator was removed and a second Garmin GI 275 MFI was installed in accordance with the same STC, but was configured as a primary ADI. Because both of these instruments were configured as primary units, a reversionary switch was not installed, nor was it required to be.

The aircraft’s owner and the occurrence pilot both thought that if a fault was detected in the ADI, the HSI would either automatically enter the reversionary operation mode and display the ADI page, or the pilot would be able to select the ADI page manually. Therefore, their understanding of both the system’s automation and the units’ reversionary capabilities was incorrect.



Incompetent salesman?
Uninformed user?
Deceptive sales pitch?
With dual GI 275 displays as your primary flight instrumentation, reversionary backup capability retains attitude and heading data on the remaining HSI or MFD if an outage should occur.

The investigation attempted to determine more precisely the source of the initial fault. However, no supplemental information about the instrument, possible reasons it would require realignment while the aircraft was in flight, or analysis of the occurrence aircraft’s recorded fault logs were provided to the investigation by Garmin.

Whew!